Sintered rare earth metal-boron-iron alloy magnets and a method for their production

Abstract

The present invention provides sintered rare earth metal-boron-iron alloy magnets having superior anti-corrosion properties in which the magnetic properties do not deteriorate with time obtained by adding at least one oxide powder chosen from the group including Al, Ga, Ni, Co, Mn, Cr, Ti, V, Nb, Y, Ho, Er, Tm, Lu, as well as Eu, as well as at least one hydride powder chosen from the group including Zr, Ta, Ti, Nb, V. Hf, and Y in an amount totalling from 0.0005 to 3.0 weight % to a R-B-Fe alloy powder; molding; sintering; and then carrying out heat treatment as necessary.

Description

FIELD OF THE INVENTION

The present invention concerns sintered magnets and a method for their production, said sintered magnets having exceedingly good anti-corrosion properties, and at the same time, magnetic properties which do not deteriorate with time. The magnets of the present invention are necessarily composed of a rare earth metal (hereafter indicated by R) component including at least one element chosen from the rare earth element group including yttrium; boron; as well as iron.

PRIOR ART

In recent years, Nd-B-Fe permanent magnets have been discovered which, in comparison with the previously known Sm-Co magnets, have improved magnetic properties, and moreover, do not necessarily include Sm and Co which are more valuable from the standpoint of resources. The manufacturing method for these Nd-B-Fe permanent magnets involves first of all melting starting materials, casting, pulverizing the thus obtained alloy ingot, then as is needed, press forming in the a magnetic field, and finally sintering.

However, with these Nd-B-Fe permanent magnets, while having improved magnetic properties, they are very liable to corrosion and also have the additional defect of severe deterioration with time of their magnetic properties.

In an attempt to solve these problems, in Japanese Patent Application No. 61-185910, a method for diffusion forming a thin zinc coating over the surface of an R-B-Fe permanent magnet, and in Japanese Patent Application No. 61-270308, a method in which the surface layer of an R-B-Fe permanent magnet is removed after which an aluminum coating layer is applied have been described.

For both of the previously stated prior art anti-corrosion methods for Nd-B-Fe permanent magnets, however, because some protective coating of zinc, aluminum, or the like must be deposited on the permanent magnet surface, in addition to the manufacturing processes for the magnet, and thus additional processes are necessary. Accordingly, the above described manufacturing methods are not only complicated, but also high cost. Furthermore, because the above anti-corrosion methods do nothing more than protect the outer portion of the permanent magnet from corrosion and the like, when the above mentioned protective coating layers exfolliate or crack, corrosion may penetrate inwards from such areas. Thus, internal corrosion is not prevented and the additional problem of deterioration of magnetic properties with such magnets also occurs.

SUMMARY OF THE INVENTION

For these reasons, in order to develop an R-B-Fe permanent magnet having superior corrosion resistant properties, the present inventors carried out research, the results of which showed that a manufacturing method for a sintered R-B-Fe magnet was possible in which first an R-B-Fe alloy powder which included at least one oxide powder chosen from the group including Al, Ga, Ni, Co, Mn, Cr, Ti, V, Nb, Y, Ho, Er, Tm, LuZr, as well as Eu oxides, plus an additive comprising a total of from 0.0005 to 3.0 weight % of at least one hydride powder chosen from the group including Zr, Ta, Ti, Nb, V, Hf, and Y hydrides were processed; pressing, sintering and carrying out heat treatment as necessary; whereby a sintered R-B-Fe magnet having improved anti-corrosion properties and no time decay of magnetic properties could be formed.

The present invention is based on the knowledge thus obtained, and the manufacturing method for an R-B-Fe sintered magnet of the present invention will be explained in detail in the following.

(1) An R-B-Fe alloy powder having a fixed composition is prepared. This R-B-Fe alloy powder is prepared by, for example, a method in which a molten alloy is cast into an ingot, then pulverized; a liquid atomization method; or a reduction-diffusion method in which a rare earth oxide is used, and the like.

The above mentioned R-B-Fe alloy powder is a mixture composed of at least one oxide powder chosen from the group including Al, Ga, Ni, Co, Mn, Cr, Ti, V, Nb, Y, Ho, Er, Tm, LuZr, as well as Eu oxides, plus an additive comprising a total of from 0.0005 to 3.0 weight % of at least one hydride powder chosen from the group including Zr, Ta, Ti, Nb, V, Hf, and Y hydrides.

The reason for establishing these limits for the additive is that with less than a weight % of 0.0005, the effectiveness of the anti-corrosion properties is insufficient, and when the weight % exceeds 3.0%, the magnetic properties are insufficient. Concerning the above mentioned additive in greater detail, as the amount of additive is increased within the limits of 0.0005 to 3.0 weight %, the magnetic property of residual flux density has a tendency to decrease. Thus, it is even more desirable to limit the amount of additive to between 0.0005 and 2.5 weight %.

Concerning the above mentioned oxides and hydrides, ordinary grades may be used. Also, when the oxide is added, if a nitride compound powder is added at the same time, the anti-corrosion and magnetic properties are even more markedly improved.

(2) The mixed powder obtained in the above step is molded by compacting in a compression press or the like. For this process, a compression pressure of 0.5-10 t/cm.sup.2 is suitable, and as required, a magnetic field (at least 5 KOe) may by applied to improve the magnetic properties. In molding, wet compaction or dry compaction are suitable, and a non-oxidizing atmosphere is desirable, for example, a vacuum, an inert gas atmosphere, or a reducing gas are all suitable. At the time of molding, a molding adjuvant (binding agent, lubricating agent, etc.) may be added as necessary. For these, paraffin, camphor, stearic amide, stearate, and the like can be used, a weight % of 0.001-2 being desirable. When the added amount of the above mentioned molding adjuvant is less than 0.001 weight %, lubrication properties required during molding are insufficient, and thus is undesirable. On the other hand, when the added amount of the above mentioned molding adjuvant is greater than 2 weight %, after sintering, degradation of a magnetic properties in the sintered body are considerable.

(3) The obtained molded body is sintered at a temperature of 900.degree.-1200.degree. C. When the sintering temperature is less than 900.degree. C., residual magnetic flux (hereafter referred to as Br) becomes insufficient. When the sintering temperature is greater than 1200.degree. C., the Br and the squareness of the demagnetization curve become low, and hence is undesirable. In order to prevent oxidization during sintering, a non-oxidizing atmosphere is desirable. That is to say, a vacuum, an inert gas, or a reducing gas atmosphere is suitable. For the rate of temperature increase during sintering, somewhere in the range of 1.degree.-2000.degree. C./min is suitable. When a molding adjuvant is used, keeping the heating rate low at 1.degree.-1.5.degree. C. /min and removing the molding adjuvant during heating will favorably effect the magnetic properties. For the sintering maintenance interval, a period of 0.5-20 hours is good. If the sintering maintenance interval is less than 0.5 hours, dispersion in the sintered density will occur. If the sintering maintenance interval is greater than 20 hours, the problem of coarseness in the crystallized grains develops. For the cooling rate after sintering, a rate of 1.degree.-2000.degree. C./min is suitable, however, if the cooling is too fast, the probability of developing cracks in the sintered body is high. Conversely, if the cooling rate is too slow, efficiency from the viewpoint of industrial productivity becomes a problem, thus the previously stated limits were decided upon.

(4) After the above sintering, to further improve magnetic characteristics, a heat treatment at a temperature of 400.degree.-700.degree. C. is carried out. Just as with sintering, this heat treatment should be carried out in an inert atmosphere. For this heat treatment, a heating rate of 10.degree.-2000.degree. C./min, a maintenance period at 400.degree.-700.degree. C. of 0.5-10 hours, and a cooling rate of 10.degree.-2000.degree. C./min is suitable. The above described heat treatment consists of heating, holding the temperature and cooling. The same results can be obtained, however, by repeating the pattern or changing the temperature in steps.

In the following, the component structure as well as the reasons for the obtained component structure will be described for a sintered rare earth metal-boron-iron alloy magnet to which the method of the present invention was applied.

For a magnet manufactured by the present invention, R, B, as well as Fe are indispensable elements, For R, Nd, Pr, as well as the mixture of these elements are suitable. Additionally, it is suitable to include rare earth elements such as Tb, Dy, La, Ce, Ho, Er, Eu, Sm, Gd, Pm, Tm, Yb, Lu, as well as Y in an total amount of 8-30 atomic %. If less than 8 atomic % is used, sufficient coercivity (hereafter referred to as iHc) cannot be obtained. If greater than 30 atomic % is added, the Br becomes low. Among the above mentioned R elements; Y, Ho, Er, Tm, Lu as well as Eu, have the fundamental property of easily imparting corrosion resistance, and for this reason, when incorporated into the R-rich phase, impart sufficient corrosion resistance in this R-rich phase. However, because when a large amount of these elements are incorporated in the main phase, there is an effect of degraded magnetic characteristics, it is desirable that these elements exist only in the inter-grain regions of R-rich phase. Accordingly, when the above specified rare earth element oxide is added, for the R-B-Fe alloy powder, it is desirable to use an alloy powder which does not include the above noted elements.

B amounts to 2-28 atomic %. When B is less than 2%, a sufficient iHc cannot be obtained, and when B is greater than 28%, the Br becomes low and superior magnetic properties cannot be obtained.

The sintered rare earth boron-iron alloy magnets are prepared using the above mentioned essential ingredients of R, B, and Fe, however, a portion of the Fe may be replaced with another element, or impurities may be present with no loss to the effect of the present invention.

That is to say, up to 50 atomic % of the Fe may be replaced by Co. If the amount of Co is greater than 50 atomic %, then a high iHc cannot be obtained. Fe may be replaced with at least one element other than the above mentioned element in amounts no greater than the below listed atomic %'s (however, when two or more elements are included, the total amount should be no greater than the value for the element having the largest permissible value) with no loss in the effect of the present invention. These elements are listed below (unit - atomic %).

______________________________________Ti: 4.7, Ni: 8.0, Bi: 5.0, W: 8.8, Zr: 5.5, Ta: 10.5,Mo 8.7, Ca: 8.0, Hf: 5.5, Ge: 6.0, Nb: 12.5, Mg: 8.0,Cr: 8.5, Sn: 3.5, Al: 9.5, Sr: 7.5, Mn: 8.0, Sb: 2.5,V: 10.5, Be: 3.5, Ba: 2.5, Cu: 3.5, S: 2.5, P: 3.3,C: 4.0, O: 1.5, Ga: 6.0______________________________________

In the present invention, the reason that adding these added components improves magnetic characteristics is that, when the R-rich liquid phase is formed during sintering, a portion of the oxidizing components are reduced and then deposited in the metal state in the inter-crystalline grain boundaries. Fundamentally, since these metals themselves have anti-corrosion properties, it is thought that they contribute to the anti-corrosion properties of the magnets thus formed.

In the following section, sintered rare earth boron-iron alloy magnets manufactured by the above described method will be discussed.

In general, the structure of rare earth boron-iron permanent magnets is, as shown in FIG. 1, composed mainly of a R.sub.2 Fe.sub.14 B.sub.1 phase a; and existing in a part of the inter-granular boundaries of said R.sub.2 Fe.sub.14 B.sub.1 phase a, an R-rich phase b (said to be composed of R.sub.95 Fe.sub.5 phase, R.sub.75 Fe.sub.25 phase, and the like); as well as a B-rich phase c made up of R.sub.1 Fe.sub.4 B.sub.4 phase. The coercivities of these magnets is a result of the fact that the magnetic phase, chief phase a is wrapped in an R-rich phase b, and that magnetic nucleus formation is restricted in the inter-granular boundaries. On the other hand however, because this R-rich phase b is inferior in regard to anti-corrosion properties, through this R-rich phase b, corrosion occurring at the inter-granular boundaries advances into the interior. For the sintered rare earth boron-iron alloy magnets of the present invention, in the inter-granular boundary phase (R-rich phase) contains 20-90 atomic % of at least one component selected from the group including Ni, Co, Mn, Cr, Ti, V, Al, Ga, In, Zr, Hf, To, Nb, Mo, Si, Re, as well as W (hereafter referred to as M), or otherwise, in addition to or instead of M, an amount of R from 20-90 atomic %, and additionally, an oxide in the amount of 30-70 atomic %. In this way, for sintered magnets incorporating M in the inter-granular boundary phase, and additionally, magnets incorporating M and/or R in the inter-granular boundary phase along with an oxide, anti-corrosive properties of the inter-granular boundary phase can be improved, and thus overall superior anti-corrosive properties can be achieved. Similarly, because the inter-granular boundary phase with its included additive elements also has a controlling effect on growth of the magnetic phase, chief phase crystal grains, these crystal grains can highly densify in their minute state, and thus also have superior magnetic properties.

With the above, when the amount of the M component of the inter-granular boundary phase is less than 20 atomic %, sufficient anti-corrosive properties cannot be obtained. On the other hand, when the amount of the M component of the inter-granular boundary phase is greater than 90 atomic %, the above mentioned M components tends to diffuse into the chief phase during manufacture, and thus while the anti-corrosive properties are improved, magnetic properties decline greatly which is unsuitable. Furthermore, in the inter-granular boundary phase, together with M and/or R, when oxygen is incorporated in an amount of 30-70 atomic %, magnetic properties do not decline and anti-corrosive properties further improve. When the above mentioned oxygen in the inter-granular boundary phase is less than 30%, the anti-corrosive properties are not further improved. On the other hand, when the oxygen in the inter-granular boundary phase is greater than 70%, the oxygen tends to diffuse into the chief phase, and the magnetic properties decline greatly which is unsuitable.

Further, for the sintered rare earth boron-iron alloy magnets of the present patent application, the content cf the chief phase R.sub.2 Fe.sub.14 B.sub.1 phase is limited to 50 to 95 volume %, the B-rich phase R.sub.1 Fe.sub.4 B.sub.4 phase is limited to 0 to 20 volume % (however, 0% is excluded), the inter-granular boundary phase R-rich phase is limited to 2 to 30 volume %.

BRIEF EXPLANATION OF THE DRAWINGS

FIG. 1 is a schematic drawing of a prior art sintered rare earth boron-iron alloy magnet.

BEST MODE FOR CARRYING OUT THE INVENTION

In the following, the present invention will be concretely explained based on a preferred embodiment, however, the present invention is in no way limited to this preferred embodiment. In the present preferred embodiment, the presence of surface rust on the sintered samples was assessed by first sectioning an anti-corrosion sintered compact, and the examining the periphery of the cut surface. If no rust could be observed at the periphery of the cut surface, the specimen was judged as "rust absent". If rust were observed at the periphery of the cut surface, the specimen was judged as "rust present". If rust were observed at the periphery of the cut surface, and furthermore, were observed to have penetrated within the specimen was judged as "rust heavy".

Examples 1-5 and Comparative Examples 1-3

A melt composed of 15% Nd, 8% B, and the remainder Fe (here % stands for atomic %) was cast into an alloy ingot. This alloy ingot was pulverized, yielding a fine powder having an average particle diameter of 3.5 .mu.m. Starting material powder was then prepared by mixing the powder thus obtained with Cr.sub.2 O.sub.3 powder of an average particle diameter of 1.2 .mu.m in the proportions indicated in Table 1. The thus obtained starting material powder was then molded in an ambient atmosphere at a molding pressure of 2 t/cm.sup.2 in a magnetic field of 14 KOe to form 12 mm L.times.10 mm W.times.10 mm H compacts. The compacts thus obtained were then heated in a vacuum (10.sup.-5 torr) at a heating rate of 5.degree. C./min to 1100.degree. C. and maintained under those conditions for 1 hr. to effect sintering, after which they were cooled at a cooling rate of 50.degree. C./min

Thereafter, the sintered compacts were heated in an argon atmosphere at a rate of 10.degree. C./min to a temperature of 620.degree. C. and maintained under those conditions for 2 hr., after which they were cooled at a rate of 100.degree. C./min to thus effect heat treatment.

The magnetic properties of the obtained heat treated sintered compacts were measured, after which an anti-corrosion test was carried out. The anti-corrosion test was carried out by leaving the compacts in an ambient atmosphere at a temperature of 60.degree. C. and humidity of 90% for 650 hr.. After carrying out the above described anti-corrosion test, the magnetic properties were again measured and examination for the formation of rust was performed, and these results are shown in Table 1.

Examples 6-10 and Comparative Examples 4-6

A melt composed of 13.5% Nd, 1.5% Dy, 8% B, and the remainder Fe (here % stands for atomic %) was cast into an alloy ingot. This alloy ingot was pulverized using a jaw crusher, disk mill, as well as a ball mill, yielding a fine powder having an average particle diameter of 3.2 .mu.m. Starting material powder was then prepared by mixing the fine powder thus obtained with TiO.sub.2 powder of an average particle diameter of 1.5 .mu.m in the proportions indicated in Table 2. The thus obtained starting material powder was then molded at a molding pressure of 1.5 t/cm.sup.2 in a magnetic field of 14 KOe to form 12 mm L.times.10 mm W.times.10 mm H compacts. The compacts thus obtained were then heated in an argon atmosphere of reduced pressure argon atmosphere (250 torr) at a heating rate of 10.degree. C./min to 1080.degree. C. and maintained under those conditions for 2 hr. to effect sintering, after which they were cooled at a cooling rate of 100.degree. C./min. Thereafter, the sintered compacts were heated in an argon atmosphere at a rate of 20.degree. C./min to a temperature of 650.degree. C. and maintained under those conditions for 1.5 hr., after which they were cooled at a rate of 100.degree. C./min to thus effect heat treatment.

The magnetic properties of the obtained heat treated TiO.sub.2 containing sintered compacts were measured, after which an anti-corrosion test was carried out by leaving the compacts in a room air atmosphere at a temperature of 60.degree. C. and humidity of 90% for 650 hr.. After carrying out the above described anti-corrosion test, the magnetic properties were again measured and examination for the formation of rust was performed, and these results were shown in Table 2.

Examples 11-16 and Comparative Examples 7-8

The above described 13.5% Nd, 1.5% Dy, 8% B, and the remainder Fe (here % stands for atomic %) alloy powders from Examples 6-10 and Comparative Examples 4-6 were combined with MnO.sub.2 powder of an average particle diameter of 1.0 .mu.m in the proportions indicated in Table 3. The thus obtained starting material powders were then molded at a molding pressure of 5 t/cm.sup.2 in a magnetic field of 12 KOe to form 12 mm L.times.10 mm W.times.10 mm H compacts. The compacts thus obtained were then heated in an argon atmosphere of reduced pressure (250 torr) at a heating rate of 15.degree. C./min to 1200.degree. C. and maintained under those conditions for 2 hr. to effect sintering, after which they were cooled at a cooling rate of 150.degree. C./min.

Thereafter, the sintered compacts were heated at a rate of 30.degree. C./min to a temperature of 650.degree. C. and maintained under those conditions for 1.5 hr., after which they were cooled at a rate of 200.degree. C./min to thus effect heat treatment. The magnetic properties of the obtained heat treated sintered compacts were measured, after which an anti-corrosion test was carried out by leaving the compacts in a room air atmosphere at a temperature of 60.degree. C. and humidity of 90% for 650 hr.. After carrying out the above described anti-corrosion test, the magnetic properties were again measured and examination for the formation of rust was performed, and these results are shown in Table 3.

Examples 17-22 and Comparative Examples 9-10

The above described 13.5% Nd, 1.5% Dy, 8% B, and the remainder Fe (here % stands for atomic %) alloy powders from Examples 6-10 and Comparative Examples 4-6 were combined with Co.sub.2 O.sub.3 powder of an average particle diameter of 1.2 .mu.m in the proportions indicated in Table 4. The thus obtained starting material powders were then molded at a molding pressure of 10 t/cm.sup.2 in a magnetic field of 20 KOe to form 20 mm L.times.20 mm W.times.15 mm H compacts. The compacts thus obtained were then heated in an argon atmosphere of reduced pressure (250 torr) at a heating rate of 20.degree. C./min to 900.degree. C. and maintained under those conditions for 20 hr. to effect sintering, after which they were cooled at a cooling rate of 500.degree. C./min.

Thereafter, the sintered compacts were heated at a rate of 1000.degree. C./min to a temperature of 500.degree. C. and maintained under those conditions for 7 hr., after which they were cooled at a rate of 500.degree. C./min..

The magnetic properties of the obtained heat treated sintered compacts were measured, after which an anti-corrosion test was carried out by leaving the compacts in a room air atmosphere at a temperature of 60.degree. C. and humidity of 90% for 650 hr.. After carrying out the above described anti-corrosion test, the magnetic properties were again measured and examination for the formation of rust was performed, and these results are shown in Table 4.

Examples 23-29 and Comparative Examples 11-12

The above described 13.5% Nd, 1.5% Dy, 8% B, and the remainder Fe (here % stands for atomic %) alloy powders from Examples 6-10 and Comparative Examples 4-6 were combined with NiO powder of an average particle diameter of 1.0 .mu.m in the proportions indicated in Table 5. The thus obtained starting material powders were then molded at a molding pressure of 1.5 t/cm.sup.2 in a magnetic field of 14 KOe to form 12 mm L.times.10 mm W.times.10 mm H compacts. The compacts thus obtained were then heated in a vacuum (10.sup.-5 torr) at a heating rate of 5.degree. C./min to 1080.degree. C. and maintained under those conditions for 1 hr. to effect sintering, after which they were cooled at a cooling rate of 50.degree. C./min.

Thereafter, the sintered compacts were heated at a rate of 20.degree. C./min to a temperature of 800.degree. C. and maintained for 1 hr., and maintained at a temperature of 620.degree. C. for 1.5 hr., after which they were cooled at a rate of 100.degree. C./min., thus effecting heat treatment.

The magnetic properties of the obtained heat treated sintered compacts were measured, after which an anti-corrosion test was carried out by leaving the compacts in a room air atmosphere at a temperature of 60.degree. C. and humidity of 90% for 650 hr.. After carrying out the above described anti-corrosion test, the magnetic properties were again measured and examination for the formation of rust was performed, and these results are shown in Table 5.

Examples 30-35 and Comparative Examples 13-14

The above described 15% Nd, 8% B, and the remainder Fe (here % stands for atomic %) alloy powders from Examples 1-5 and Comparative Examples 1-3 were combined with V.sub.2 O.sub.5 powder of an average particle diameter of 1.4 .mu.m in the proportions indicated in Table 6. The thus obtained starting material powders were then molded at a molding pressure of 7 t/cm.sup.2 in a magnetic field of 20 KOe to form 20 mm L.times.20 mm W .times.15 mm H compacts. The compacts thus obtained were then heated in a vacuum (10.sup.-5 torr) at a heating rate of 100.degree. C./min to 1000.degree. C. and maintained under those conditions for 10 hr. to effect sintering, after which they were cooled at a cooling rate of 300.degree. C./min.

Thereafter, the sintered compacts were heated at a rate of 100.degree. C./min to a temperature of 550.degree. C. and maintained for 2 hr. under those conditions after which they were cooled at a rate of 300.degree. C./min., thus effecting heat treatment.

The magnetic properties of the obtained heat treated sintered compacts were measured, after which an anti-corrosion test was carried out by leaving the compacts in a room air atmosphere at a temperature of 60.degree. C. and humidity of 90% for 650 hr.. After carrying out the above described anti-corrosion test, the magnetic properties were again measured and examination for the formation of rust was performed, and these results are shown in Table 6.

Examples 36-41 and Comparative Examples 15-16

The above described 15% Nd, 8% B, and the remainder Fe (here % stands for atomic %) alloy powders from Examples 1-5 and Comparative Examples 1-3 were combined with Nb.sub.2 O.sub.3 powder of an average particle diameter of 1.2 .mu.m in the proportions indicated in Table 7. The thus obtained starting material powders were then molded at a molding pressure of 1 t/cm.sup.2 in a magnetic field of 5 KOe to form 12 mm L.times.10 mm W .times.10 mm H compacts. The compacts thus obtained were then heated in a vacuum (10.sup.-5 torr) at a heating rate of 3.degree. C./min to 1200.degree. C. and maintained under those conditions for 1.5 hr. to effect sintering, after which they were cooled at a cooling rate of 5.degree. C./min.

Thereafter, the sintered compacts were heated at a rate of 20.degree. C./min to a temperature of 450.degree. C. and maintained for 2 hr. under those conditions after which they were cooled at a rate of 900.degree. C./min , thus effecting heat treatment.

The magnetic properties of the obtained heat treated sintered compacts were measured, after which an anti-corrosion test was carried out by leaving the compacts in a room air atmosphere at a temperature of 60.degree. C. and humidity of 90% for 650 hr.. After carrying out the above described anti-corrosion test, the magnetic properties were again measured and examination for the formation of rust was performed, and these results are shown in Table 7.

Examples 42-54 and Comparative Examples 17-21

The above described 13.5% Nd, 1.5% Dy, 8% B, and the remainder Fe (here % stands for atomic %) alloy powders from Examples 6-10 and Comparative Examples 4-6 were combined with at least two kinds of oxide powders chosen from Cr.sub.2 O.sub.3 (average particle diameter: 1.2 .mu.m), NiO (average particle diameter: 1.0 .mu.m), Co.sub.2 O.sub.3 (average particle diameter: 1.2 .mu.m), MnO.sub.2 (average particle diameter: 1.0 .mu.m), TiO.sub.2 (average particle diameter: 1.5 .mu.m), V.sub.2 O.sub.5 (average particle diameter: 1.4 .mu.m), as well as Nb.sub.2 O.sub.3 (average particle diameter: 1.2 .mu.m), in the proportions indicated in Table 8.

The thus obtained starting material powders were then molded at a molding pressure of 1.5 t/cm.sup.2 in a magnetic field of 14 KOe to form 12 mm L.times.10 mm W.times.10 mm H compacts. The compacts thus obtained were then heated in an argon atmosphere of reduced pressure (250 torr) at a heating rate of 10.degree. C./min to 1080.degree. C. and maintained under those conditions for 2 hr. to effect sintering, after which they were cooled at a cooling rate of 100.degree. C./min.

Thereafter, the sintered compacts were heated in an argon gas atmosphere at a rate of 20.degree. C./min to a temperature of 650.degree. C. and maintained under those conditions for 1.5 hr., after which they were cooled at a rate of 100.degree. C./min to thus effect heat treatment. The magnetic properties of the obtained heat treated oxide containing sintered compacts were measured, after which an anti-corrosion test was carried out by leaving the compacts in a room air atmosphere at a temperature of 60.degree. C. and humidity of 90% for 650 hr.. After carrying out the above described anti-corrosion test, the magnetic properties were again measured and examination for the formation of rust was performed, and these results are shown in Table 8.

From the results in Tables 1-8 concerning the above described alloy powders from Examples 1-54 and Comparative Examples 1-21, it can be understood that for sintered magnets manufactured by molding R-B-Fe alloy powders and sintering, rust forms on the surface after the anti-corrosion test, and that rust diffuses within causing marked corrosion, and that after the anti-corrosion test, the deterioration of magnetic properties is remarkable. However, when a sintered magnet is manufactured using as a starting material powder one to which is added at least one kind of oxide chosen from the group including Ni, Co, Mn, Cr, Ti, V, and Nb, the total amount being 0.0005-3.0 weight %, a sintered magnet having superior anti-corrosion properties can be manufactured. And further, it can be understood that with such a magnet, that the deterioration of magnetic properties after the anti-corrosion test can be restrained.

With sintered magnets manufactured from an R-B-Fe alloy powder in which the total added amount of the above mentioned oxides exceeds 3.0 weight %, rust formation on the surface cannot be seen, however, the magnetic properties of the magnet itself decline. When using a starting material powder in which total added amount of the above mentioned oxides is less than 0.0005 weight %, rust forms on the surface of the sintered magnet, and after the anti-corrosion test, deterioration of magnetic properties is remarkable.

Examples 55-94 and Comparative Examples 22-38

First of all, a melt composed of 13.5% Nd, 1.5% Dy, 8% B, and the remainder Fe (here % stands for atomic %) was cast into an alloy ingot.

This alloy ingot was pulverized, yielding a fine powder having an average particle diameter of 3.5 .mu.m. Starting material powders were then prepared by mixing the powder thus obtained with 1.2 .mu.m average particle diameter Al.sub.2 O.sub.3 powder, ZrO.sub.2 powder, Cr.sub.2 O.sub.3 powder, and TiO.sub.2 powder in the proportions indicated in Table 9 for Examples 55-94 and Comparative Examples 22-38. The thus obtained starting material powders were then molded in room air at a molding pressure of 1.5 t/cm.sup.2 in a magnetic field of 14 KOe to form 12 mm L.times.10 mm W.times.10 mm H compacts. The compacts thus obtained were then heated in a vacuum (10.sup.-5 torr) at a heating rate of 5.degree. C./min to 1100.degree. C. and maintained under those conditions for 1 hr. to effect sintering, after which they were cooled at a cooling rate of 50.degree. C./min

Thereafter, the sintered compacts were heated in an argon atmosphere at a rate of 10.degree. C./min to a temperature of 620.degree. C. and maintained under those conditions for 2 hr., after which they were cooled at a rate of 100.degree. C./min to thus effect heat treatment.

The magnetic properties of the obtained heat treated sintered compacts were measured, after which an anti-corrosion test was carried out. The anti-corrosion test was carried out by leaving the compacts in a room air atmosphere at a temperature of 60.degree. C. and humidity of 90% for 650 hr.. After carrying out the above described anti-corrosion test, the magnetic properties were again measured and examination for the formation of rust was performed, and these results are shown in Table 9.

From the results in Table 9 concerning the above described alloy powders, it can be understood that for sintered magnets manufactured by molding R-B-Fe alloy powders and sintering, rust forms on the surface after the anti-corrosion test, and that rust diffuses within causing marked corrosion, and that after the anti-corrosion test, the deterioration of magnetic properties is remarkable. However, when a sintered magnet is manufactured using as a starting material powder one to which Al.sub.2 O.sub.3 powder is added in an amount of 0.0005-3.0 weight %, or one to which Al.sub.2 O.sub.3 powder is added plus at least one kind of oxide powder chosen from the group including Zr, Cr, and Ti, the total amount being 0.0005-3.0 weight %, a sintered magnet having superior anti-corrosion properties can be manufactured. And further, it can be understood that with such a magnet, that the deterioration of magnetic properties after the anti-corrosion test can be restrained.

With sintered magnets manufactured from an R-B-Fe alloy powder in which the total added amount of the above mentioned oxides exceeds 3.0 weight %, rust formation on the surface cannot be seen, however, the magnetic properties of the magnet itself decline. When using a starting material powder in which total added amount of the above mentioned oxides is less than 0.0005 weight %, rust forms on the surface of the sintered magnet, and after the anti-corrosion test, decline of magnetic properties is remarkable.

Examples 95-134 and Comparative Examples 39-55

First of all, a melt composed of 13.5% Nd, 1.5% Dy, 8% B, and the remainder Fe (here % stands for atomic %) was cast into an alloy ingot.

This alloy ingot was pulverized, yielding a fine powder having an average particle diameter of 3.5 .mu.m. Starting material powders were then prepared by mixing the powder thus obtained with 1.2 .mu.m average particle diameter Ga.sub.2 O.sub.3 powder, Al.sub.2 O.sub.3 powder, Cr.sub.2 O.sub.3 powder, and V.sub.2 O.sub.5 powder in the proportions indicated in Table 10 for Examples 95-134 and Comparative Examples 39-55. The thus obtained starting material powders were then molded in room air at a molding pressure of 1.5 t/cm.sup.2 in a magnetic field of 14 KOe to form 12 mm L.times.10 mm W.times.10 mm H compacts. The compacts thus obtained were then heated in a vacuum (10.sup.-5 torr) at a heating rate of 5.degree. C./min to 1100.degree. C. and maintained under those conditions for 1 hr. to effect sintering, after which they were cooled at a cooling rate of 50.degree. C./min.

Thereafter, the sintered compacts were heated in an argon atmosphere at a rate of 10.degree. C./min to a temperature of 620.degree. C. and maintained under those conditions for 2 hr., after which they were cooled at a rate of 100.degree. C./min to thus effect heat treatment.

The magnetic properties of the obtained heat treated sintered compacts were measured, and those results are shown in Table 10 under "Magnetic Properties Prior to Anti-Corrosion Test".

After the above mentioned magnetic properties were measured, the anti-corrosion test was carried out by leaving the compacts in a room air atmosphere at a temperature of 60.degree. C. and humidity of 90% for 650 hr.. After carrying out the above described anti-corrosion test, the magnetic properties were again measured and those results are shown in Table 10 under "Magnetic Properties After Anti-Corrosion Test", and examination for the formation of rust was performed, these results are also shown in Table 10.

From the results in Table 10 concerning the above described alloy powders, it can be understood that for sintered magnets manufactured by molding R-B-Fe alloy powders and sintering, rust forms on the surface after the anti-corrosion test, and that rust diffuses within causing marked corrosion, and that after the anti-corrosion test, the deterioration of magnetic properties is remarkable. However, when a sintered magnet is manufactured using as a starting material powder one to which Ga.sub.2 O.sub.3 powder is added in an amount of 0.0005-3.0 weight %, or one to which Ga.sub.2 O.sub.3 powder is added plus at least one kind of oxide powder chosen from the group including Al, Cr, and V, the total amount being 0.0005-3.0 weight %, a sintered magnet having superior anti-corrosion properties can be manufactured. And further, it can be understood that with such a magnet, that the deterioration of magnetic properties after the anti-corrosion test can be restrained.

With sintered magnets manufactured from an R-B-Fe alloy powder in which the total added amount of the above mentioned oxides exceeds 3.0 weight %, rust formation on the surface cannot be seen, however, the magnetic properties of the magnet itself decline. When using a starting material powder in which total added amount of the above mentioned oxides is less than 0.0005 weight %, rust forms on the surface of the sintered magnet, and after the anti-corrosion test, decline of magnetic properties is remarkable.

Examples 135-179 and Comparative Examples 56-73

First of all, a melt composed of 15% Nd, 8% B, and the remainder Fe (here % stands for atomic %) was cast into an alloy ingot. This alloy ingot was pulverized, yielding a fine powder having an average particle diameter of 3.5 .mu.m.

Then, as hydride powders,

______________________________________ZnH.sub.2 powder: 1.3 mum average particle diameter,TaH.sub.2 powder: 1.5 mum average particle diameter,TiH.sub.2 powder: 1.3 mum average particle diameter,NbH.sub.2 powder: 1.3 mum average particle diameter,VH powder: 1.5 mum average particle diameter,HfH.sub.2 powder: 1.3 mum average particle diameter,YH.sub.3 powder: 1.1 mum average particle diameter,______________________________________ were prepared, from which starting material powders were prepared by mixing the powder thus obtained in the proportions indicated in Table 11.

The thus obtained starting material powders were then molded in an argon gas atmosphere at a molding pressure of 1.5 t/cm.sup.2 in a magnetic field of 12 KOe to form 12 mm L.times.10 mm W.times.10 mm H compacts.

The compacts thus obtained were then heated in an argon atmosphere at 1 atm. at a heating rate of 10.degree. C./min to 1090.degree. C. and maintained under those conditions for 1 hr., after which they were cooled at a cooling rate of 100.degree. C./min to effect sintering. Thereafter, the sintered compacts were heated in the same atmosphere as the above heat treating atmosphere at a rate of 5.degree. C./min to a temperature of 620.degree. C. and maintained under those conditions for 2 hr., after which they were cooled at a rate of 50.degree. C./min to effect heat treatment, thus manufacturing as shown in table 11, the sintered rare earth boron-iron alloy magnets 135-179 of the present invention and the comparative example sintered rare earth boron-iron alloy magnets 56-73.

The magnetic properties of the above prepared sintered rare earth metal-boron-iron alloy magnets 135-170 of the present invention and the comparative example sintered rare earth metal-boron-iron alloy magnets 56-73 were measured (residual magnetic flux: Br, coercivity: iHc, as well as maximum energy product: BH.sub.max), after which the anti-corrosion test was carried out for the respective sintered magnets by leaving the compacts in a room air atmosphere at a temperature of 60.degree. C. and humidity of 90% for 1000 hr.. After carrying out the above described anti-corrosion test, the magnetic properties of the sintered rare earth boron-iron alloy magnets 135-170 of the present invention and the comparative example sintered rare earth boron-iron alloy magnets 56-73 were measured (residual magnetic flux: Br, coercivity: iHc, as well as maximum energy product: BH.sub.max), and the surface and interior of the sintered magnets was examined for the presence of rust. The respective results are shown in Table 11.

From the results in Table 11, it can be understood that for the comparative example sintered rare earth boron-iron alloy magnet 56 molded from R-B-Fe alloy powder alone, rust forms on the surface after the anti-corrosion test, and that the rust diffuses within causing marked corrosion, and that after the anti-corrosion test, the deterioration of magnetic properties is remarkable. However, when the sintered rare earth boron-iron alloy magnets of the present invention are manufactured using as a starting material powder one to which one or two or more kinds of hydride powders chosen from the group including Zr, Ta, Ti, Nb, V, Hf, as well as Y, the total amount being 0.0005-3 weight % are added, a sintered magnet having superior anti-corrosion properties can be manufactured. And further, it can be understood that with such a magnet, that there is no appearance of the deterioration of magnetic properties after the anti-corrosion test.

With the comparative example sintered rare earth boron-iron alloy magnets 58, 60, 62, 64, 66, 68, 70, 72, and 73 manufactured from an R-B-Fe alloy powder in which the total added amount of the above mentioned hydrides exceeds 3 weight %, rust formation on the surface cannot be seen, however, the magnetic properties decline. With the comparative example sintered rare earth boron-iron alloy magnets 57, 59, 61, 63, 65, 67, 69, and 71 manufactured from an R-B-Fe alloy powder in which the total added amount of the above mentioned hydrides is less than 0.0005 weight %, in all cases, rust forms on the surface of the sintered magnet, and after the anti-corrosion test, decline of magnetic properties is remarkable.

Examples 180-215 and Comparative Examples 74-89

First of all, a melt composed of 13.5% Nd, 1.5% Dy, 8% B, and the remainder Fe (here % stands for atomic %) was cast into an alloy ingot.

This alloy ingot was pulverized, yielding a fine powder having an average particle diameter of 3.5 .mu.m.

Then, as oxide powders,

Y.sub.2 O.sub.3 powder: 1.2 mum average particle diameter, Ho.sub.2 O.sub.3 powder: 1.1 mum average particle diameter, Er.sub.2 O.sub.3 powder: 1.2 mum average particle diameter, Tm.sub.2 O.sub.3 powder: 1.2 mum average particle diameter, Lu.sub.2 O.sub.3 powder: 1.1 mum average particle diameter, Eu.sub.2 O.sub.3 powder: 1.0 mum average particle diameter, were prepared. From the respective powders, starting material powders were prepared by mixing in the proportions indicated in Table 12 for Examples 180-215 and Comparative Examples 74-89. The thus obtained starting material powders were then molded in an argon gas atmosphere at a molding pressure of 1.5 t/cm.sup.2 in a magnetic field of 14 KOe to form 12 mm L.times.10 mm W.times.10 mm H compacts. The compacts thus obtained were then heated in a vacuum (10.sup.-5 torr) at a heating rate of 5.degree. C./min to 1100.degree. C. and maintained under those conditions for 1 hr. to effect sintering, after which they were cooled at a cooling rate of 50.degree. C./min.

Thereafter, the sintered compacts were heated in an argon gas atmosphere at a rate of 10.degree. C./min to a temperature of 620.degree. C. and maintained under those conditions for 2 hr., after which they were cooled at a rate of 10.degree. C./min to effect heat treatment.

The magnetic properties of the above prepared sintered heat treated compacts were measured and are shown in Table 12 under "Prior to Anti-Corrosion Test".

After measuring the above magnetic properties, the anti-corrosion test was carried out for the respective sintered magnets by leaving the compacts in a room air atmosphere at a temperature of 80.degree. C. and humidity of 90% for 1000 hr., after which the magnetic properties were again measured and are shown in Table 12 under "After Anti-Corrosion Test".

From the results in Table 12, it can be understood that for the comparative example sintered rare earth boron-iron alloy magnet 74 molded from R-B-Fe alloy powder alone, rust can be seen on the surface after the anti-corrosion test, and that the rust diffuses within, and that after the anti-corrosion test, the deterioration of magnetic properties is remarkable. However, when the sintered rare earth boron-iron alloy magnets 180-215 of the present invention are manufactured using as a starting material powder one to which one or two or more kinds of oxide powders chosen from the group including Y, Ho, Er, Tm, Lu, as well as Eu, the total amount being 0.0005-3.0 weight % are added, a sintered magnet having superior anti-corrosion properties can be manufactured. And further, it can be understood that with such a magnet, that rust cannot be seen and there is no appearance of the decline of magnetic properties after the anti-corrosion test.

With the comparative example sintered rare earth boron-iron alloy magnets 76, 78, 80, 82, 84, 86, 88, and 89 manufactured from an R-B-Fe alloy powder in which the total added amount of the above mentioned oxides exceeds 3.0 weight %, rust formation is absent and anti-corrosion properties are superior, however, the magnetic properties are exceedingly low. With the comparative example sintered rare earth metal-boron-iron alloy magnets 75, 77, 79, 81, 83, 85, and 87 manufactured from an R-B-Fe alloy powder in which the total added amount of the above mentioned oxides is less than 0.0005 weight %, in all cases, rust forms on the surface of the sintered magnet, and after the anti-corrosion test, decline of magnetic properties is remarkable.

Examples 216-300 and Comparative Examples 90-119

x xA melt composed of 15% Nd, 8% B, and the remainder Fe (here % stands for atomic %) was cast into an alloy ingot. This alloy ingot was pulverized, yielding a fine powder having an average particle diameter of 3.5 .mu.m.

As additive powders, 1.2 .mu.m average particle diameter Cr.sub.2 O.sub.3 powder, as well as 1.5 .mu.m average particle diameter CrN powder, MnN.sub.4 powder, ZrN powder, HfN powder, TiN powder, NbN powder, Ni.sub.2 N powder, Si.sub.3 N.sub.4 powder, GeN powder, VN powder, GaN powder, AlN powder, and Co.sub.3 N powder were prepared

The above powders were blended according to the proportions indicated in Table 13, then molded in room air atmosphere at a molding pressure of 2 t/cm.sup.2 in a magnetic field of 14 KOe to form 12 mm L.times.10 mm W.times.10 mm H compacts. The compacts thus obtained were then heated in a vacuum (10.sup.-5 torr) at a heating rate of 5.degree. C./min to 1100.degree. C. and maintained under those conditions for 1 hr. to effect sintering, after which they were cooled at a cooling rate of 50.degree. C./min.

Thereafter, the sintered compacts were heated in an argon gas atmosphere at a rate of 10.degree. C./min to a temperature of 620.degree. C. and maintained under those conditions for 2 hr., after which they were cooled at a rate of 100.degree. C./min to thus effect heat treatment.

The magnetic properties of the obtained heat treated sintered compacts were measured, after which the anti-corrosion test was carried out by leaving the compacts in a room air atmosphere at a temperature of 60.degree. C. and humidity of 90% for 650 hr.. After carrying out the above described anti-corrosion test, the magnetic properties were again measured and examination for the formation of rust was performed, these results are shown in Table 13.

From the results in Table 13, it can be understood that it is necessary to add 1 or 2 or more nitride powders chosen from the group including Cr, Mn, Zr, Hf, Ti, Nb, Ni, Si, Ge, V, Ga, Al, and Co in an amount of 0.0005-3.0 weight % together with Cr.sub.2 O.sub.3 powder in an amount of 0.0005-3.0 weight % to a 15% Nd, 8% B, and the remainder Fe (here % stands for atomic %) powder in order to attain superior anti-corrosion and magnet properties.

That is to say, it can be understood that when the above mentioned nitride powders are added alone in the range of 0.0005-3.0 weight %, sufficient anti-corrosion properties are not obtained, and when Cr.sub.2 O.sub.3 powder is added alone in the range of 0.0005-3.0 weight %, sufficient magnetic properties are not obtained.

Examples 301-381 and Comparative Examples 120-150

An alloy ingot prepared from a melt composed of 13.5% Nd, 1.5% Dy, 8% B, and the remainder Fe (here % stands for atomic %) was pulverized, yielding a rare earth boron-iron alloy powder having an average particle diameter of 3.0 .mu.m.

As additive powders, 1.0 .mu.m average particle diameter NiO powder, as well as 1.5 .mu.m average particle diameter CrN powder, MnN.sub.4 powder, ZrN powder, HfN powder, TiN powder, NbN powder, Ni.sub.2 N powder, Si.sub.3 N.sub.4 powder, GeN powder, VN powder, GaN powder, AlN powder, and Co.sub.3 N powder were prepared.

The above powders were blended according to the proportions indicated in Table 14, then molded in room air at a molding pressure of 10 t/cm.sup.2 in a magnetic field of 20 KOe to form 20 mm L.times.20 mm W.times.15 mm H compacts.

The compacts thus obtained were then heated in an argon atmosphere of reduced pressure at 250 Torr, at a heating rate of 20.degree. C./min to 900.degree. C. and maintained under those conditions for 20 hr. to effect sintering, after which they were cooled at a cooling rate of 500.degree. C./min

Thereafter, the sintered compacts were heated in an argon atmosphere at a rate of 1000.degree. C./min to a temperature of 500.degree. C. and maintained under those conditions for 7 hr., after which they were cooled at a rate of 500.degree. C./min to thus effect heat treatment.

The magnetic properties of the obtained heat treated sintered compacts were measured, after which the anti-corrosion test was carried out by leaving the compacts in a room air atmosphere at a temperature of 60.degree. C. and humidity of 90% for 650 hr.. After carrying out the above described anti-corrosion test, the magnetic properties were again measured and examination for the formation of rust was performed. These results are shown in Table 14.

From the results in Table 14, it can be understood that it is necessary to add 1 or 2 or more nitride powders chosen from the group including Cr, Mn, Zr, Hf, Ti, Nb, Ni, Si, Ge, V, Ga, Al, and Co in an amount of 0.0005-3.0 weight % together with NiO powder in an amount of 0.0005-3.0 weight % to a 13.5% Nd, 1.5% Dy, 8% B, and the remainder Fe (here % stands for atomic %) powder in order to attain superior anti-corrosion and magnet properties, and furthermore, decline in magnetic properties due to corrosion is prevented.

Examples 382-394 and Comparative Examples 151-156

The following powders were prepared,

______________________________________Cr.sub.2 O.sub.3 powder: 1.2 mum average particle diameter,NiO powder: 1.0 mum average particle diameter,CrN powder: 1.5 mum average particle diameter,MnN.sub.4 powder: 1.8 mum average particle diameter,ZrN powder: 1.2 mum average particle diameter,HfN powder: 1.5 mum average particle diameter,TiN powder: 1.3 mum average particle diameter,NbN powder: 1.3 mum average particle diameter,Ni.sub.2 N powder: 1.5 mum average particle diameter,Si.sub.3 N.sub.4 powder: 1.5 mum average particle diameter,GeN powder: 1.5 mum average particle diameter,VN powder: 1.4 mum average particle diameter,GaN powder: 1.1 mum average particle diameter,AlN powder: 1.5 mum average particle diameter,Co.sub.3 N powder: 1.5 mum average particle diameter,______________________________________ and according to the proportions shown in Table 15, the two above oxides and two or more of the above nitrides were mixed with an 3.0 .mu.m average diameter 13.5% Nd, 1.5% Dy, 8% B, and the remainder Fe (here % stands for atomic %) alloy powder, and the resulting mixed powders were press molded at a molding pressure of 1.5 t/cm.sup.2 in a magnetic field of 14 KOe to form 12 mm L.times.10 mm W.times.10 mm H compacts. The compacts thus obtained were then heated in an argon atmosphere of reduced pressure at 250 Torr, at a heating rate of 10.degree. C./min to 1080.degree. C. and maintained under those conditions for 2 hr. to effect sintering, after which they were cooled at a cooling rate of 100.degree. C./min.

Thereafter, the sintered compacts were heated in an argon gas atmosphere at a rate of 20.degree. C./min to a temperature of 620.degree. C. and maintained under those conditions for 1.5 hr., after which they were cooled at a rate of 100.degree. C./min to thus effect heat treatment. The magnetic properties of the obtained heat treated, oxide containing, sintered compacts were measured, after which the anti-corrosion test was carried out by leaving the compacts in a room air atmosphere at a temperature of 60.degree. C. and humidity of 90% for 650 hr.. After carrying out the above described anti-corrosion test, the magnetic properties were again measured and examination of their surfaces for the formation of rust was performed. These results are shown in Table 16.

From the results in Table 16, it can be understood that for sintered magnets obtained by preparing a mixture of an amount of Cr.sub.2 O.sub.3 and NiO totaling within the range of 0.0005 and 3.0 weight %, and an amount of two or more of the above nitride powders totaling within the range of 0.0005 and 3.0 weight %, and further adding this oxide and nitride mixture to a rare earth boron-iron alloy powder, that superior anti-corrosion and magnetic properties are obtained, and further, because there is no loss of magnetic properties after the anti-corrosion test, decline in magnetic properties due to corrosion is prevented.

From the results of the above mentioned Tables 13-16, as with Comparative Example 150, with sintered magnets obtained from rare earth boron-iron alloy powder, rust forms on the surface after the anti-corrosion test, and this corrosion penetrates within leading to extensive corrosion. However, with sintered magnets obtained from a starting material powder including a total of one or two Cr and Ni oxides ranging from 0.0005 and 3.0 weight %, and a total of one or two or more additives chosen from Cr, Mn, Zr, Hf, Ti, Nb, Ni, Si, Ge, V, Ga, Al, as well as Co ranging from 0.0005 and 3.0 weight %, sintered magnets having superior anti-corrosion and magnetic properties can be formed, and further, that decline in magnetic properties due to corrosion can be prevented, and the superior effect of producing sintered rare earth metal-boron-iron alloy magnets that require no surface treatment can be achieved with the manufacturing method of the present invention.

Examples 395-411 and Comparative Example 157

First of all, a melt composed of 15% Nd, 8% B, and the remainder Fe (here % stands for atomic %) was cast into an alloy ingot. Thereafter, the ingot was heated in an argon atmosphere at 1050.degree. C. for 20 hr. to effect heat treatment, then pulverized to yield 3.5 .mu.m average particle diameter rare earth metal-boron-iron alloy powder.

Then as additive powders, NiO (average particle diameter: 1.0 .mu.m), Co.sub.2 O.sub.3 (average particle diameter: 1.2 .mu.m), MnO.sub.2 (average particle diameter: 1.0 .mu.m), Cr.sub.2 O.sub.3 (average particle diameter: 1.2 .mu.m), TiO.sub.2 (average particle diameter: 1.5 .mu.m), V.sub.2 O.sub.5 (average particle diameter: 1.4 .mu.m), Al.sub.2 O.sub.3 (average particle diameter: 1.2 .mu.m), Ga.sub.2 O.sub.3 (average particle diameter: 1.2 .mu.m), In.sub.2 O.sub.3 (average particle diameter: 1.4 .mu.m), ZrO.sub.2 (average particle diameter: 1.2 .mu.m), HfO.sub.2 (average particle diameter: 1.2 .mu.m), Nb.sub.2 O.sub.3 (average particle diameter: 1.3 .mu.m), Dy.sub.2 O.sub.3 (average particle diameter: 1.2 .mu.m), and Y.sub.2 O.sub.3 (average particle diameter 1.0 .mu.m) were prepared.

The above mentioned rare earth metal-boron-iron alloy powder and one or two or more of the above mentioned oxide additive powders in an amount within the range of 0.0005-2.5 weight % were combined and blended. This blended powder was then molded at a molding pressure of 2 t/cm.sup.2 in a magnetic field of 14 KOe to form 20 mm L.times.20 mm W.times.15 mm H compacts. The compacts thus obtained were then heated in a vacuum (10.sup.-5 torr) at a heating rate of 10.degree. C./min to 1080.degree. C. and maintained under those conditions for 2 hr. to effect sintering, after which they were cooled at a cooling rate of 100.degree. C./min.

Thereafter, the sintered compacts were heated at a rate of 100.degree. C./min to a temperature of 620.degree. C. and maintained under those conditions for 2 hr., after which they were cooled at a rate of 100.degree. C./min to thus effect heat treatment.

The structure of these sintered heat treated compacts was investigated, and it was found that it was formed from R.sub.2 Fe.sub.14 B phase as well as inter-granular boundary phase, having a structure generally the same as that of FIG. 1. The results of STEM measurement are shown in Table 17. Further, the magnetic properties of the above mentioned sintered heat treated compacts were measured, and then a anti-corrosion test was carried out by keeping the compacts at 60.degree. C. and 90% humidity for 1000 hours after which the magnetic properties were again measured, while at the same time, examination for the presence of rust was carried out. These results are shown in Table 17.

Examples 412-422

As additive powders, ZrH.sub.2 powder (average particle diameter: 1.3 .mu.m), TaH.sub.2 powder (average particle diameter: 1.5 .mu.m), TiH.sub.2 powder (average particle diameter: 1.3 .mu.m), NbH.sub.2 powder (average particle diameter: 1.3 .mu.m), VH powder (average particle diameter: 1.5 .mu.m), HfH.sub.2 powder (average particle diameter: 1.3 .mu.m), as well as YH.sub.3 powder (average particle diameter: 1.1 .mu.m) were prepared. These powders were combined in fixed proportions in an amount within the range of 0.0005-3.0 weight % with the above mentioned 15% Nd, 8% B, and the remainder Fe (here % stands for atomic %) rare earth metal-boron-iron alloy powder prepared in Examples 395-411, then blended, after which these blended powders were processed in a manner entirely identical to that of the above mentioned Examples 395-411, and in the same way, the metal elements making up the inter-granular boundary phase were measured using STEM. After the magnetic properties were measured, the anti-corrosion test was carried out. After carrying out the above described anti-corrosion test, the magnetic properties were again measured and examination for the formation of rust was performed, and these results are shown in Table 18.

From the results in Tables 17 and 18, it can be understood that compared with the prior art examples in which metal elements and oxygen are not incorporated in the inter-granular boundary phase, the sintered rare earth metal-boron-iron alloy magnets of the present invention in which metal elements, or both metal elements and oxygen are incorporated in the inter-granular boundary phase are superior in respect to both magnetic properties and anti-corrosion properties.

TABLE 1__________________________________________________________________________ Magnetic Properties Magnetic Properties Cr.sub.2 O.sub.3 Prior to the After the Added Observed Anti-Corrosion Test Anti-Corrosion Test Amount Rust Br iHc BH.sub.max Br iHc BH.sub.maxSample (Weight %) Condition (Kg) (KOe) (MGOe) (Kg) (KOe) (MGOe)__________________________________________________________________________Example 1 0.0006 rust 12.4 12.7 37.0 12.2 12.0 35.0 absentExample 2 0.5 rust 12.3 12.5 35.8 12.2 12.0 35.0 absentExample 3 1.1 rust 12.3 12.4 35.5 12.2 12.2 35.0 absentExample 4 1.5 rust 12.2 12.4 35.0 12.2 12.2 34.3 absentExample 5 2.2 rust 12.1 12.5 34.0 12.1 12.4 34.0 absentComparative none rust 12.4 12.5 37.0 12.0 5.0 22.5Example 1 added heavyComparative 0.0001 rust 12.4 12.5 37.0 12.1 5.6 22.7Example 2 presentComparative 3.1 rust 11.2 5.0 19.2 12.1 5.0 19.0Example 3 absent__________________________________________________________________________ TABLE 2__________________________________________________________________________ Magnetic Properties Magnetic Properties TiO.sub.2 Prior to the After the Added Observed Anti-Corrosion Test Anti-Corrosion Test Amount Rust Br iHc BH.sub.max Br iHc BH.sub.maxSample (Weight %) Condition (Kg) (KOe) (MGOe) (Kg) (KOe) (MGOe)__________________________________________________________________________Example 6 0.0005 rust 11.8 20 34.0 11.7 16.1 32.0 absentExample 7 0.1 rust 11.8 20 33 11.7 17.5 31.6 absentExample 8 0.5 rust 11.8 19.0 32.8 11.7 17.5 31.8 absentExample 9 1.5 rust 11.7 18.5 32.0 11.7 18.0 31.5 absent Example 10 2.5 rust 11.6 18.0 31.5 11.6 18.0 31.5 absentComparative none rust 12.0 20 34.8 10.5 8.1 22.1Example 4 added heavyComparative 0.0002 rust 11.8 20 34.0 10.6 10.5 23.0Example 5 presentComparative 3.1 rust 10.2 12.1 22.6 10.2 12.0 22.2Example 6 absent__________________________________________________________________________ TABLE 3__________________________________________________________________________ Magnetic Properties Magnetic Properties MnO.sub.2 Prior to the After the Added Observed Anti-Corrosion Test Anti-Corrosion Test Amount Rust Br iHc BH.sub.max Br iHc BH.sub.maxSample (Weight %) Condition (Kg) (KOe) (MGOe) (Kg) (KOe) (MGOe)__________________________________________________________________________Example 11 0.0007 rust 11.8 19.6 33.6 11.7 18.2 33.0 absentExample 12 0.2 rust 11.7 18.7 33.0 11.7 18.0 32.8 absentExample 13 0.7 rust 11.7 17.5 32.5 11.7 17.0 32.5 absentExample 14 1.4 rust 11.5 17.3 32.0 11.5 17.0 32.0 absentExample 15 2.0 rust 11.5 17.0 31.7 11.5 17.0 31.7 absentExample 16 2.5 rust 11.5 16.5 31.1 11.5 16.5 31.1 absentComparative 0.0003 rust 11.8 19.5 33.6 10.7 10.4 23.5Example 7 presentComparative 3.1 rust 10.6 12.1 23.5 10.6 12.0 23.5Example 8 absent__________________________________________________________________________ TABLE 4__________________________________________________________________________ Magnetic Properties Magnetic Properties Cr.sub.2 O.sub.3 Prior to the After the Added Observed Anti-Corrosion Test Anti-Corrosion Test Amount Rust Br iHc BH.sub.max Br iHc BH.sub.maxSample (Weight %) Condition (Kg) (KOe) (MGOe) (Kg) (KOe) (MGOe)__________________________________________________________________________Example 17 0.0006 rust 11.8 20 34.0 11.7 18.6 33.5 absentExample 18 0.001 rust 11.8 19.5 34.0 11.7 19.0 33.8 absentExample 19 0.01 rust 11.8 19.1 34.0 11.8 18.5 33.2 absentExample 20 0.4 rust 11.8 18.5 33.2 11.8 17.8 32.5 absentExample 21 1.1 rust 11.7 18.0 32.5 11.7 17.7 32.5 absentExample 22 2.3 rust 11.6 17.5 32.1 11.6 17.5 32.1 absentComparative 0.0001 rust 11.8 20 34.0 10.7 11.4 22.0Example 9 presentComparative 3.1 rust 10.2 10.5 18.1 10.2 10.4 18.0 Example 10 absent__________________________________________________________________________ TABLE 5__________________________________________________________________________ Magnetic Properties Magnetic Properties Cr.sub.2 O.sub.3 Prior to the After the Added Observed Anti-Corrosion Test Anti-Corrosion Test Amount Rust Br iHc BH.sub.max Br iHc BH.sub.maxSample (Weight %) Condition (Kg) (KOe) (MGOe) (Kg) (KOe) (MGOe)__________________________________________________________________________Example 23 0.0006 rust 11.8 19.5 34.0 11.7 19.4 32.8 absentExample 24 0.001 rust 11.8 19.0 34.0 11.7 18.5 32.7 absentExample 25 0.1 rust 11.7 18.7 33.0 11.7 18.0 32.5 absentExample 26 1.0 rust 11.7 18.0 32.8 11.7 17.1 32.5 absentExample 27 1.5 rust 11.7 18.0 32.5 11.7 17.0 32.5 absentExample 28 2.3 rust 11.7 17.8 32.5 11.7 17.0 32.5 absentComparative 11 0.0002 rust 11.9 20 34.1 10.5 10.2 22.1Example presentComparative 12 3.1 rust 10.2 12.0 23.0 10.1 11.8 22.8Example absent__________________________________________________________________________ TABLE 6__________________________________________________________________________ Magnetic Properties Magnetic Properties Cr.sub.2 O.sub.3 Prior to the After the Added Observed Anti-Corrosion Test Anti-Corrosion Test Amount Rust Br iHc BH.sub.max Br iHc BH.sub.maxSample (Weight %) Condition (Kg) (KOe) (MGOe) (Kg) (KOe) (MGOe)__________________________________________________________________________Example 30 0.0007 rust 12.4 12.4 35.9 12.2 11.9 35.5 absentExample 31 0.01 rust 12.3 12.5 35.8 12.1 11.8 35.1 absentExample 32 0.5 rust 12.3 12.3 35.0 12.3 12.1 35.0 absentExample 33 1.0 rust 12.2 12.2 34.5 12.2 12.2 34.4 absentExample 34 1.7 rust 12.2 12.3 34.5 12.2 12.2 34.5 absentExample 35 2.4 rust 12.1 12.0 34.0 12.1 12.0 34.0 absentComparative 13 0.0002 rust 12.4 12.5 37.0 12.0 5.1 22.5Example presentComparative 14 3.1 rust 11.2 5.1 19.2 11.0 5.0 18.6Example absent__________________________________________________________________________ TABLE 7__________________________________________________________________________ Magnetic Properties Magnetic Properties Cr.sub.2 O.sub.3 Prior to the After the Added Observed Anti-Corrosion Test Anti-Corrosion Test Amount Rust Br iHc BH.sub.max Br iHc BH.sub.maxSample (Weight %) Condition (Kg) (KOe) (MGOe) (Kg) (KOe) (MGOe)__________________________________________________________________________Example 36 0.0005 rust 12.4 12.6 37.0 12.2 12.2 35.5 absentExample 37 0.01 rust 12.3 12.5 35.7 12.2 12.3 35.5 absentExample 38 0.5 rust 12.2 12.5 35.1 12.2 12.4 35.1 absentExample 39 1.2 rust 12.1 12.3 35.0 12.1 12.2 35.0 absentExample 40 1.8 rust 12.1 12.3 35.0 12.1 12.3 35.0 absentExample 41 2.4 rust 12.0 12.0 34.0 12.0 12.0 34.0 absentComparative 15 0.0001 rust 12.4 12.6 37.0 12.0 5.1 20.1Example presentComparative 16 3.1 rust 11.0 4.5 19.0 11.0 4.5 19.0Example absent__________________________________________________________________________ TABLE 8__________________________________________________________________________ Prior to the After theAmount of Oxide Powder Added Corrosion Test Corrosion Testto R--B--Fe Alloy Powder (Weight %) Rust Br iHc BH.sub.max Br iHc BH.sub.maxSample Cr.sub.2 O.sub.3 NiO CO.sub.2 O.sub.3 MnO.sub.2 TiO.sub.2 V.sub.2 O.sub.5 Nb.sub.2 O.sub.3 Total State KG KOe MGOe KG KOe MGOe__________________________________________________________________________EXAMPLES42 0.2 -- 0.5 -- -- -- -- 0.7 absent 11.7 18.5 32.5 11.6 18.0 32.143 0.5 -- -- 0.3 -- 0.1 -- 0.9 absent 11.8 18.4 32.7 11.7 18.0 32.544 -- 0.5 -- -- 0.5 -- 0.5 1.5 absent 11.7 17.8 32.2 11.7 17.0 31.845 0.8 -- -- 1.0 -- 0.2 -- 2.0 absent 11.7 17.6 32.0 11.7 17.5 32.046 1.0 0.1 0.1 0.1 0.1 0.1 0.1 1.6 absent 11.7 17.8 32.0 11.7 17.8 31.847 1.5 0.3 -- -- 0.3 -- -- 2.1 absent 11.7 17.6 32.0 11.7 17.5 32.048 0.1 0.3 0.3 0.2 0.5 -- -- 1.4 absent 11.7 18.1 32.2 11.7 17.7 31.849 1.7 0.01 0.01 -- -- 0.02 0.02 1.76 absent 11.7 18.1 32.1 11.7 17.7 32.050 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0007 absent 11.8 19.5 34.0 11.7 16.5 32.151 2.3 -- -- 0.05 0.05 -- -- 2.4 absent 11.7 17.6 32.0 11.7 17.4 33.652 -- -- -- -- 0.7 -- 0.7 1.4 absent 11.8 18.1 33.8 11.8 17.8 32.053 -- -- -- -- 0.1 0.9 1.0 2.0 absent 11.7 17.7 32.0 11.7 17.7 33.554 -- 0.2 -- 0.8 0.1 0.3 -- 1.4 absent 11.8 17.8 33.7 11.8 17.6 23.1COMPARATIVE EXAMPLES17 0.0001 0.0001 -- -- -- -- -- 0.0002* present 11.8 20.0 34.0 11.0 9.0 22.018 1.5 -- 1.6 -- -- -- -- 3.1* absent 10.1 11.1 22.1 10.1 11.0 23.219 2.0 0.009 0.1 0.1 0.8 0.09 0.001 3.1* absent 10.5 12.0 23.2 10.5 12.0 23.220 0.2 0.5 1.0 0.8 0.7 -- -- 3.2* absent 10.6 11.0 23.5 10.6 10.9 23.321 0.0001 -- 0.0001 -- 0.0001 -- 0.0001 0.0004* present 11.8 19.8 33.8 11.0 9.2 23.2__________________________________________________________________________ *indicates values outside of the conditions of the present invention TABLE 9-1__________________________________________________________________________ Starting Material Powder Composition (Weight %) Prior to the After the Oxides Added Corrosion Test Corrosion Test to R--B--Fe Alloy Powder R--B--Fe Rust Br iHc BH.sub.max Br iHc BH.sub.maxSample Al.sub.2 O.sub.3 ZrO.sub.2 Cr.sub.2 O.sub.3 TiO.sub.2 Total Alloy Powder State KG KOe MGOe KG KOe MGOe__________________________________________________________________________EXAMPLES55 0.0007 -- -- -- 0.0007 remainder absent 12.0 20.1 34.7 11.8 18.0 33.656 0.06 -- -- -- 0.06 remainder absent 11.9 20.3 34.1 11.9 19.2 34.057 0.6 -- -- -- 0.6 remainder absent 11.9 21.0 34.2 11.9 20.5 34.158 1.0 -- -- -- 1.0 remainder absent 11.8 21.5 34.0 11.8 21.0 33.859 2.2 -- -- -- 2.2 remainder absent 11.7 21.8 33.4 11.7 21.2 33.360 0.0002 0.04 -- -- 0.0402 remainder absent 12.0 20.1 34.9 11.9 20.0 34.061 0.04 2.0 -- -- 2.04 remainder absent 11.9 20.3 34.1 11.9 20.2 34.062 0.3 1.4 -- -- 1.7 remainder absent 11.9 21.3 34.2 11.9 21.3 34.263 1.1 0.05 -- -- 1.15 remainder absent 11.8 21.7 34.0 11.8 21.7 34.064 2.0 0.0003 -- -- 2.0003 remainder absent 11.7 21.9 33.4 11.7 21.9 33.465 0.0002 -- 0.007 -- 0.0072 remainder absent 12.0 20.3 35.0 11.9 20.0 34.366 0.05 -- 2.3 -- 2.35 remainder absent 11.9 20.8 34.4 11.9 20.8 34.467 0.5 -- 1.2 -- 1.7 remainder absent 11.9 21.5 34.5 11.9 21.5 34.568 1.0 -- 0.3 -- 1.3 remainder absent 11.8 22.0 34.0 11.8 21.8 33.869 2.3 -- 0.0004 -- 2.3004 remainder absent 11.7 22.2 33.6 10.7 22.0 33.570 0.0002 -- -- 0.05 0.0502 remainder absent 11.9 20.1 34.3 10.9 19.5 34.071 0.06 -- -- 2.1 2.16 remainder absent 11.7 22.0 33.5 10.7 21.9 33.5__________________________________________________________________________ *the composition of the rare earth metalboron-iron alloy powder is Nd13.5%, Dy1.5%, B8%, Feremainder (here % is atomic %) TABLE 9-2__________________________________________________________________________ Starting Material Powder Composition (Weight %) Prior to the After the Oxides Added Corrosion Test Corrosion Test to R--B--Fe Alloy Powder R--B--Fe Rust Br iHc BH.sub.max Br iHc BH.sub.maxSample Al.sub.2 O.sub.3 ZrO.sub.2 Cr.sub.2 O.sub.3 TiO.sub.2 Total Alloy Powder State KG KOe MGOe KG KOe MGOe__________________________________________________________________________EXAMPLES72 0.4 -- -- 1.0 1.4 remainder absent 11.8 22.1 34.0 11.8 22.0 33.973 1.0 -- -- 0.2 1.2 remainder absent 11.8 22.0 34.0 11.8 21.7 33.874 2.4 -- -- 0.0005 2.4005 remainder absent 11.7 22.6 33.5 11.7 22.5 33.575 0.4 0.1 0.2 -- 0.7 remainder absent 11.8 21.5 33.9 11.8 21.5 33.976 0.4 0.5 0.4 -- 1.3 remainder absent 11.8 22.1 34.1 11.8 22.1 34.177 1.0 0.3 0.5 -- 1.8 remainder absent 11.8 22.5 34.2 11.8 22.3 34.278 1.5 0.7 0.2 -- 2.4 remainder absent 11.7 22.5 33.3 11.7 22.3 33.379 0.2 -- 0.05 0.1 0.35 remainder absent 11.9 20.5 34.3 11.9 20.3 34.280 0.001 -- 0.01 0.01 0.021 remainder absent 11.9 19.7 34.1 11.9 19.4 33.981 0.3 -- 0.6 0.5 1.4 remainder absent 11.8 22.0 34.1 11.8 22.0 34.182 0.1 -- 0.1 1.7 1.9 remainder absent 11.8 22.5 34.3 11.8 22.5 34.383 0.2 -- 1.6 0.5 2.3 remainder absent 11.7 22.6 33.5 11.7 22.6 33.584 1.0 0.5 -- 0.6 2.1 remainder absent 11.7 22.1 33.2 11.7 22.1 33.185 0.3 0.2 -- 0.1 0.6 remainder absent 11.8 21.4 34.0 11.8 21.3 34.086 0.1 1.3 -- 0.1 1.5 remainder absent 11.8 22.0 34.2 11.8 22.0 34.287 0.001 0.01 -- 0.1 0.111 remainder absent 11.9 20.2 34.2 11.8 19.5 34.088 0.3 0.3 -- 0.3 0.9 remainder absent 11.8 21.8 34.0 11.8 21.7 33.9__________________________________________________________________________ *the composition of the rare earth metalboron-iron alloy powder is Nd13.5%, Dy1.5%, B8%, Feremainder (here % is atomic %) TABLE 9-3__________________________________________________________________________ Prior to the After theStarting Material Powder Composition (Weight %) Corrosion Test Corrosion TestOxides Added to R--B--Fe Alloy Powder Rust Br iHc BH.sub.max Br iHc BH.sub.maxSample Al.sub.2 O.sub.3 ZrO.sub.2 Cr.sub.2 O.sub.3 TiO.sub.2 Total R--B--Fe Alloy Powder State KG KOe MGOe KG KOe MGOe__________________________________________________________________________EXAMPLES89 0.0005 0.0001 0.0001 0.0001 0.0008 remainder absent 11.9 20.2 34.0 11.8 19.7 33.690 0.01 0.01 0.01 0.01 0.04 remainder absent 11.9 20.5 34.3 11.8 20.0 34.091 0.2 0.1 0.1 0.1 0.5 remainder absent 11.8 20.8 33.7 11.8 20.6 33.692 0.4 0.2 0.1 0.4 1.1 remainder absent 11.8 21.8 34.0 11.8 21.7 34.093 0.5 0.5 0.4 0.4 1.8 remainder absent 11.8 22.0 34.1 11.8 22.0 34.194 0.6 0.6 0.6 0.5 2.3 remainder absent 11.7 22.5 33.3 11.7 22.5 33.3COMPARATIVEEXAMPLES22 -- -- -- -- none# remainder heavy 12.0 20.0 34.8 10.5 8.1 22.123 0.0002 -- -- -- 0.0002# remainder present 12.0 20.1 34.8 10.6 9.2 23.024 3.3# -- -- -- 3.3# remainder absent 10.3 12.0 22.3 10.3 12.0 22.325 0.0002 0.0001 -- -- 0.0003# remainder present 12.0 20.0 34.8 10.7 10.1 21.526 2.3 0.8 -- -- 3.1# remainder absent 10.2 11.5 22.1 10.2 11.5 22.127 0.0003 -- 0.0001 -- 0.0004# remainder present 11.9 20.4 34.2 10.6 9.8 21.328 2.2 -- 1.0 -- 3.2# remainder absent 10.3 12.1 23.2 10.3 12.1 23.129 0.0002 -- -- 0.0002 0.0004# remainder present 12.0 20.1 34.8 10.6 9.4 23.030 2.0 -- -- 1.1 3.1# remainder absent 10.4 12.3 22.5 10.4 12.3 22.531 0.0001 0.0001 0.0001 -- 0.0003# remainder present 12.0 20.2 34.8 10.7 10.0 21.432 2.0 0.3 0.8 -- 3.1# remainder absent 10.4 12.0 23.1 10.4 12.0 23.1__________________________________________________________________________ *the composition of the rare earth metalboron-iron alloy powder is Nd13.5%, Dy1.5%, B8%, Feremainder (here % is atomic %) #indicates values outside of the conditions of the present invention TABLE 9-4__________________________________________________________________________ Prior to the After theStarting Material Powder Composition (Weight %) Corrosion Test Corrosion TestOxides Added to R--B--Fe Alloy Powder Rust Br iHc BH.sub.max Br iHc BH.sub.maxSample Al.sub.2 O.sub.3 ZrO.sub.2 Cr.sub.2 O.sub.3 TiO.sub.2 Total R--B--Fe Alloy Powder State KG KOe MGOe KG KOe MGOe__________________________________________________________________________COMPARATIVEEXAMPLES33 0.0001 -- 0.0001 0.0001 0.0003# remainder present 12.0 19.5 34.7 10.5 9.9 22.734 1.1 -- 0.1 2.0 3.2# remainder absent 10.2 10.8 22.0 10.2 10.8 22.035 0.0001 0.0001 -- 0.0001 0.0003# remainder present 11.9 19.6 34.4 10.5 10.1 22.836 2.0 0.6 -- 0.5 3.7# remainder absent 10.8 11.2 24.3 10.8 11.2 24.337 0.0001 0.0001 0.0001 0.0001 0.0004# remainder present 11.9 20.1 33.9 10.4 8.3 19.338 1.0 0.6 0.6 0.7 3.2# remainder absent 10.8 11.0 24.0 10.8 11.4 24.0__________________________________________________________________________ *the composition of the rare earth metalboron-iron alloy powder is Nd13.5%, Dy1.5%, B8%, Feremainder (here % is atomic %) #indicates values outside of the conditions of the present invention TABLE 10-1__________________________________________________________________________ Prior to the After theStarting Material Powder Composition (Weight %) Corrosion Test Corrosion TestOxides Added to R--B--Fe Alloy Powder Br iHc BH.sub.max Br iHc BH.sub.max RustSample Ga.sub.2 O.sub.3 Al.sub.2 O.sub.3 Cr.sub.2 O.sub.3 V.sub.2 O.sub.5 Total R--B--Fe Alloy Powder* KG KOe MGOe KG KOe MGOe State__________________________________________________________________________EXAMPLES 95 0.0007 -- -- -- 0.0007 remainder 11.9 20.2 34.1 11.8 20.0 33.7 absent 96 0.07 -- -- -- 0.07 remainder 11.9 20.8 34.2 11.9 20.6 34.1 absent 97 0.5 -- -- -- 0.5 remainder 11.9 21.1 34.2 11.9 21.0 34.2 absent 98 1.0 -- -- -- 1.0 remainder 11.8 21.3 34.0 11.8 21.3 34.0 absent 99 2.4 -- -- -- 2.4 remainder 11.7 21.5 33.5 11.7 21.5 33.5 absent100 0.0002 0.05 -- -- 0.0502 remainder 11.9 21.0 34.2 11.8 20.7 33.8 absent101 0.06 1.5 -- -- 1.56 remainder 11.8 21.3 34.0 11.8 21.1 33.9 absent102 0.5 1.5 -- -- 2.0 remainder 11.8 21.4 34.0 11.8 21.4 34.0 absent103 1.1 0.03 -- -- 1.13 remainder 11.8 21.1 34.0 11.8 20.9 33.9 absent104 2.0 0.0002 -- -- 2.0002 remainder 11.8 20.9 33.9 11.8 20.9 33.9 absent105 0.0002 -- 0.005 -- 0.0052 remainder 11.9 20.3 34.1 11.8 19.9 33.7 absent106 0.05 -- 2.0 -- 2.05 remainder 11.8 21.3 34.0 11.8 21.3 34.0 absent107 0.5 -- 1.0 -- 1.5 remainder 11.8 20.8 33.9 11.8 20.7 33.8 absent108 1.0 -- 0.1 -- 1.1 remainder 11.8 20.7 33.8 11.8 20.6 33.8 absent109 2.2 -- 0.0005 -- 2.2005 remainder 11.7 21.0 33.4 11.7 21.0 33.4 absent110 0.0002 -- -- 0.07 0.0702 remainder 11.9 20.0 34.0 11.9 19.8 33.7 absent111 0.06 -- -- 2.2 2.26 remainder 11.7 21.4 33.5 11.7 21.4 33.5 absent112 0.3 -- -- 1.0 1.3 remainder 11.8 20.8 33.9 11.8 20.7 33.8 absent113 1.0 -- -- 0.1 1.1 remainder 11.8 20.6 33.8 11.8 20.4 33.7 absent114 2.3 -- -- 0.0005 2.3005 remainder 11.7 21.0 33.4 11.7 21.0 33.4 absent__________________________________________________________________________ *the composition of the rare earth metalboron-iron alloy powder is Nd13.5%, Dy1.5%, B8%, Feremainder (here % is atomic %) TABLE 10-2__________________________________________________________________________ Prior to the After theStarting Material Powder Composition (Weight %) Corrosion Test Corrosion TestOxides Added to R--B--Fe Alloy Powder Br iHc BH.sub.max Br iHc BH.sub.max RustSample Ga.sub.2 O.sub.3 Al.sub.2 O.sub.3 Cr.sub.2 O.sub.3 V.sub.2 O.sub.5 Total R--B--Fe Alloy Powder KG KOe MGOe KG KOe MGOe State__________________________________________________________________________EXAMPLES115 0.1 0.3 0.2 -- 0.6 remainder 11.9 20.5 34.2 11.8 20.1 33.7 absent116 0.2 0.5 0.5 -- 1.2 remainder 11.8 21.0 33.9 11.8 20.9 33.9 absent117 0.7 0.5 0.5 -- 1.7 remainder 11.8 21.2 34.0 11.8 21.1 33.9 absent118 0.6 1.0 0.6 -- 2.2 remainder 11.7 22.0 33.6 11.7 22.0 33.6 absent119 0.2 -- 1.4 0.4 2.0 remainder 11.7 21.3 33.5 11.7 21.2 33.5 absent120 0.001 -- 0.01 0.02 0.031 remainder 11.9 20.6 34.2 11.9 20.4 34.2 absent121 0.4 -- 0.7 0.5 1.6 remainder 11.8 20.7 33.8 11.8 20.6 33.8 absent122 0.1 -- 0.2 1.5 1.8 remainder 11.8 21.0 33.9 11.8 20.9 33.9 absent123 0.3 -- 1.7 0.1 2.1 remainder 11.8 21.3 34.0 11.8 21.3 34.0 absent124 1.0 0.5 -- 0.4 1.9 remainder 11.8 21.4 34.1 11.8 21.3 34.0 absent125 0.2 0.2 -- 0.2 0.6 remainder 11.9 20.6 34.2 11.8 20.4 33.7 absent126 0.1 1.3 -- 0.3 1.7 remainder 11.8 21.5 34.2 11.8 21.4 34.1 absent127 0.001 0.01 -- 0.01 0.111 remainder 11.8 21.0 33.9 11.8 20.7 33.8 absent128 0.3 0.3 -- 0.3 0.9 remainder 11.8 21.5 34.1 11.8 21.1 33.9 absent129 0.0004 0.0001 0.0001 0.0001 0.0007 remainder 11.9 20.1 34.0 11.8 19.8 33.6 absent130 0.01 0.01 0.01 0.01 0.04 remainder 11.9 20.7 34.2 11.8 20.5 33.7 absent131 0.2 0.1 0.1 0.1 0.5 remainder 11.8 20.6 33.8 11.8 20.5 33.7 absent132 0.3 0.4 0.1 0.2 1.0 reaminder 11.8 21.0 34.0 11.8 21.0 34.0 absent133 0.4 0.4 0.4 0.4 1.6 remainder 11.8 21.4 34.2 11.8 21.4 34.2 absent134 0.5 0.6 0.5 0.7 2.3 remainder 11.7 22.0 33.6 11.7 22.0 33.6 absent__________________________________________________________________________ *the composition of the rare earth metalboron-iron alloy powder is Nd13.5%, Dy1.5%, B8%, Feremainder (here % is atomic %) TABLE 10-3__________________________________________________________________________ Prior to the After theStarting Material Powder Composition (Weight %) Corrosion Test Corrosion TestOxides Added to R--B--Fe Alloy Powder Br iHc BH.sub.max Br iHc BH.sub.max RustSample Ga.sub.2 O.sub.3 Al.sub.2 O.sub.3 Cr.sub.2 O.sub.3 V.sub.2 O.sub.5 Total R--B--Fe Alloy Powder KG KOe MGOe KG KOe MGOe State__________________________________________________________________________COMPARATIVE EXAMPLES39 -- -- -- -- none# remainder 12.0 20.0 34.8 10.5 8.1 22.1 heavy40 0.0002 -- -- -- 0.0002# remainder 12.0 20.1 34.8 10.6 8.8 22.9 present41 3.2 -- -- -- 3.2# remainder 10.4 12.2 22.7 10.4 12.1 22.7 absent42 0.0002 0.0001 -- -- 0.0003# remainder 12.0 20.3 34.9 10.6 9.8 21.3 present43 2.2 0.8 -- -- 3.0# remainder 10.2 11.8 22.5 10.2 11.7 22.5 absent44 0.0003 -- 0.0001 -- 0.0004# remainder 11.9 20.1 34.1 10.7 10.8 23.0 present45 2.3 -- 0.8 -- 3.1# remainder 10.4 10.5 20.9 10.4 10.5 20.9 absent46 0.0002 -- -- 0.0002 0.0004# remainder 11.9 20.2 34.1 10.6 9.7 21.2 present47 2.2 -- -- 1.1 3.3# remainder 10.3 11.8 22.8 10.3 11.8 22.8 absent48 0.0001 0.0001 0.0001 -- 0.0003# remainder 11.9 20.2 34.1 10.7 10.1 22.0 present49 2.0 0.4 0.7 -- 3.1# remainder 10.4 12.1 23.2 10.4 12.1 23.2 absent50 0.0001 -- 0.0001 0.0001 0.0003# remainder 12.0 20.0 34.8 10.7 10.2 22.1 present51 1.0 -- 0.5 2.0 3.5# remainder 10.2 12.2 22.2 10.2 12.2 22.2 absent52 0.0001 00001 -- 0.0001 0.0003# remainder 11.9 20.1 34.1 10.6 12.3 23.3 present53 2.0 0.6 -- 0.5 3.1# remainder 10.5 11.5 23.3 10.5 11.4 23.2 absent54 0.0001 0.0001 0.0001 0.0001 0.0004# remainder 11.9 20.2 34.1 11.7 12.0 23.4 present55 1.0 0.6 0.9 0.6 3.1# remainder 10.5 11.6 23.4 10.5 11.6 23.4 absent__________________________________________________________________________ *the composition of the rare earth metalboron-iron alloy powder is Nd13.5%, Dy1.5%, B8%, Feremainder (here % is atomic %) TABLE 11-1 MAGNETIC CHARACTERISTICS STARTING MATERIAL COMPOSITION (WEIGHT %) PRIOR TO CORROSION TEST AFTER CORROSION TEST HYDRIDE POWDERS R--B--Fe Br iHc BH max Br iHc BH max SAMPLE ZrH.sub.2 TaH.sub.2 TiH.sub.2 NbH.sub.2 VH HfH.sub.2 YH.sub.3 TOTAL ALLOY POWDER RUST STATE (KG) (KOe) ( MGOe) (KG) (KOe) (MGOe) SINTERED R--B--Fe MAGNETS OF THE PRESENT INVENTION 135 0.0006 -- -- -- -- -- -- 0.0006 BALANCE ABSENT 12.6 13.5 38.0 12.4 13.3 37.5 136 0.1 -- -- -- -- -- -- 0.1 BALANCE ABSENT 12.5 13.8 38.0 12.5 13.7 38.0 137 2.5 -- -- -- -- -- -- 2.5 BALANCE ABSENT 12.5 13.9 38.0 12.5 13.9 38.0 138 -- 0.0006 -- -- -- -- -- 0.0006 BALANCE ABSENT 12.6 13.4 38.0 12.4 13.0 37.2 139 -- 0.09 -- -- -- -- -- 0.09 BALANCE ABSENT 12.5 13.5 37.8 12.5 13.4 37.7 140 -- 2.4 -- -- -- -- -- 2.4 BALANCE ABSENT 12.5 13.6 37.8 12.5 13.5 37.8 141 -- -- 0.0007 -- -- -- -- 0.0007 BALANCE ABSENT 12.6 13.8 38.2 12.5 13.4 37.7 142 -- -- 1.0 -- -- -- -- 1.0 BALANCE ABSENT 12.5 14.5 38.3 12.5 14.4 38.3 143 -- -- 2.0 -- -- -- -- 2.0 BALANCE ABSENT 12.5 14.6 38.3 12.5 14.5 38.3 144 -- -- -- 0.0006 -- -- -- 0.0006 BALANCE ABSENT 12.6 13.6 38.0 12.4 13.1 37.3 145 -- -- -- 1.1 -- -- -- 1.1 BALANCE ABSENT 12.5 13.9 38.1 12.5 13.8 38.0 146 -- -- -- 2.2 -- -- -- 2.2 BALANCE ABSENT 12.5 14.0 38.0 12.5 14.0 38.0 147 -- -- -- -- 0.0007 -- -- 0.0007 BALANCE ABSENT 12.6 13.8 38.2 12.5 13.3 37.6 148 -- -- -- -- 0.9 -- -- 0.9 BALANCE ABSENT 12.5 14.1 38.1 12.5 14.0 38.0 149 -- -- -- -- 2.3 -- -- 2.3 BALANCE ABSENT 12.5 14.2 38.2 12.5 14.2 38.2 150 -- -- -- -- -- 0.0007 -- 0.0007 BALANCE ABSENT 12.6 13.4 38.0 12.4 12.9 37.1 151 -- -- -- -- -- 1.0 -- 1.0 BALANCE ABSENT 12.5 13.7 37.9 12.5 13.5 37.8 152 -- -- -- -- -- 2.4 -- 2.4 BALANCE ABSENT 12.5 13.8 38.1 12.5 13.7 38.0 TABLE 11-2 STARTING MATERIAL COMPOSITION (WEIGHT %) MAGNETIC CHARACTERISTICS R--B--Fe PRIOR TO CORROSION TEST AFTER CORROSION TEST HYDRIDE POWDERS ALLOY RUST Br iHc BH max Br iHc BH max SAMPLE ZrH.sub.2 TaH.sub.2 TiH.sub.2 NbH.sub.2 VH HfH.sub.2 YH.sub.3 TOTAL POWDER STATE (KG) (KOe) (MGOe) (KG) (KOe) (MGOe) SINTERED R--B--Fe MAGNETS OF THE PRESENT INVENTION 153 -- -- -- -- -- -- 0.0007 0.0007 BALANCE ABSENT 12.6 13.7 38.1 12.5 13.3 37.6 154 -- -- -- -- -- -- 0.1 0.1 BALANCE ABSENT 12.5 14.1 38.1 12.5 13.9 37.9 155 -- -- -- -- -- -- 2.8 2.8 BALANCE ABSENT 12.5 14.2 38.1 12.5 14.0 38.0 156 0.0002 -- 0.0002 0.0002 -- -- 0.0001 0.0007 BALANCE ABSENT 12.6 13.7 38.1 12.5 13.5 37.8 157 -- 0.1 -- -- 0.1 -- -- 0.2 BALANCE ABSENT 12.5 14.1 38.1 12.5 13.8 37.8 158 0.3 0.3 -- -- -- -- -- 0.6 BALANCE ABSENT 12.5 14.1 38.1 12.5 13.9 38.0 159 0.5 -- 0.5 -- -- -- -- 1.0 BALANCE ABSENT 12.5 14.3 38.2 12.5 14.0 38.0 160 0.3 -- -- 0.3 -- 0.3 -- 0.9 BALANCE ABSENT 12.5 14.2 38.1 12.5 13.9 38.0 161 1.0 -- -- -- 0.5 -- -- 1.5 BALANCE ABSENT 12.5 14.2 38.1 12.5 14.0 38.0 162 1.0 -- -- -- -- -- 0.1 1.1 BALANCE ABSENT 12.5 14.0 38.0 12.5 13.9 38.0 163 0.5 0.5 -- 0.5 -- 0.5 -- 2.0 BALANCE ABSENT 12.5 14.2 38.1 12.5 14.1 38.1 164 -- 0.3 0.5 -- -- -- -- 0.8 BALANCE ABSENT 12.5 14.2 38.1 12.5 13.8 37.8 165 -- -- -- 0.1 0.3 -- -- 0.4 BALANCE ABSENT 12.5 13.8 37.8 12.5 13.4 37.7 166 -- -- -- -- -- 0.4 0.5 0.9 BALANCE ABSENT 12.5 14.2 38.1 12.5 14.0 38.0 167 -- 1.3 -- 1.5 -- -- -- 2.8 BALANCE ABSENT 12.5 14.3 38.2 12.5 14.2 38.1 168 -- -- 0.01 -- 0.1 -- -- 0.11 BALANCE ABSENT 12.5 14.1 38.1 12.5 13.8 37.8 169 -- -- -- 0.3 -- 0.3 -- 0.6 BALANCE ABSENT 12.5 13.8 37.8 12.5 13.5 37.7 170 -- -- -- -- 0.8 -- 0.2 1.0 BALANCE ABSENT 12.5 14.1 38.1 12.5 13.9 37.9 TABLE 11-3 STARTING MATERIAL COMPOSITION (WEIGHT %) MAGNETIC CHARACTERISTICS R--B--Fe BEFORE CORROSION TEST AFTER CORROSION TEST HYDRIDE POWDERS ALLOY RUST Br iHc BH max Br iHc BH max SAMPLE ZrH.sub.2 TaH.sub.2 TiH.sub.2 NbH.sub.2 VH HfH.sub.2 YH.sub.3 TOTAL POWDER STATE (KG) (KOe) (MGOe) (KG) (KOe) (MGOe) SINTERED R--B--Fe MAGNETS OF THE PRESENT INVENTION 171 0.02 -- 0.02 -- 0.02 -- 0.02 0.08 BALANCE ABSENT 12.6 13.8 38.5 12.5 13.5 37.8 172 -- 0.03 -- 0.3 -- 0.3 -- 0.63 BALANCE ABSENT 12.5 14.0 38.0 12.5 13.8 38.0 173 0.001 -- 0.002 -- -- 0.1 -- 0.103 BALANCE ABSENT 12.5 13.9 38.0 12.5 13.5 37.8 174 0.01 0.02 -- 0.02 -- 0.03 0.01 0.09 BALANCE ABSENT 12.5 13.8 38.0 12.5 13.3 37.6 175 -- 0.03 -- 0.02 0.02 0.02 0.01 0.10 BALANCE ABSENT 12.5 13.8 38.0 12.5 13.5 37.8 176 -- -- 0.01 0.01 0.01 0.01 0.01 0.05 BALANCE ABSENT 12.5 13.7 37.9 12.5 13.4 37.7 177 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.007 BALANCE ABSENT 12.6 13.6 37.8 12.5 13.3 37.6 178 -- -- 0.2 0.2 0.2 -- -- 0.6 BALANCE ABSENT 12.5 14.1 38.1 12.5 14.0 38.0 179 0.4 0.4 0.4 0.4 0.4 0.4 0.4 2.8 BALANCE ABSENT 12.5 14.3 38.2 12.5 14.2 38.2 COMPARATIVE SINTERED R--B--Fe MAGNETS 56 -- -- -- -- -- -- -- 0 BALANCE MARKED 12.5 12.5 36.8 11.2 7.5 22.0 57 0.0003 -- -- -- -- -- --0.0003 BALANCE PRESENT 12.6 13.3 37.8 11.8 10.3 26.5 58 3.5 -- -- -- -- -- -- 3.5 BALANCE ABSENT 11.5 7.5 24.1 11.5 7.5 24.1 59 -- 0.0002 -- -- -- -- -- 0.0002 BALANCE PRESENT 12.5 13.2 37.8 11.7 10.1 25.7 60 -- 3.3 -- -- -- -- -- 3.3 BALANCE ABSENT 11.4 7.6 24.0 11.4 7.6 24.0 61 -- -- 0.0003 -- -- -- -- 0.0003 BALANCE PRESENT 12.6 13.3 37.9 11.7 10.2 25.8 62 -- -- 3.6 -- -- -- -- 3.6 BALANCE ABSENT 11.5 7.9 24.2 11.5 7.9 24.2 63 -- -- -- 0.0003 -- -- -- 0.0003 BALANCE PRESENT 12.6 13.2 37.8 11.6 9.9 24.8 64 -- -- -- 3.4 -- -- -- 3.4 BALANCE ABSENT 11.5 7.7 24.1 11.5 7.7 24.1 indicates values outside of the conditions of the present invention TABLE 11-4__________________________________________________________________________STARTING MATERIAL COMPOSITION (WEIGHT %) R--B--FeHYDRIDE POWDERS ALLOYSAMPLE ZrH.sub.2 TaH.sub.2 TiH.sub.2 NbH.sub.2 VH HfH.sub.2 YH.sub.3 TOTAL POWDER__________________________________________________________________________COMPARATIVESINTEREDR--B--Fe MAGNETS65 -- -- -- -- 0.0003 -- -- 0.0003 BALANCE66 -- -- -- -- 3.5 -- -- 3.5 BALANCE67 -- -- -- -- -- 0.0003 -- 0.0003 BALANCE68 -- -- -- -- -- 3.4 -- 3.4 BALANCE69 -- -- -- -- -- -- 0.0003 0.0003 BALANCE70 -- -- -- -- -- -- 3.5 3.5 BALANCE71 0.0001 0.0001 0.0001 -- -- -- -- 0.0003 BALANCE72 0.5 0.5 0.5 0.5 0.5 0.5 0.5 3.5 BALANCE73 1.8 -- 1.8 -- -- -- -- 3.6 BALANCE__________________________________________________________________________ MAGNETIC CHARACTERISTICS PRIOR TO AFTER CORROSION TEST CORROSION TEST RUST Br iHc BH max Br iHc BH max SAMPLE STATE (KG) (KOe) (MGOe) (KG) (KOe) (MGOe)__________________________________________________________________________ COMPARATIVE SINTERED R--B--Fe MAGNETS 65 PRESENT 12.6 13.1 37.6 11.5 8.0 24.2 66 ABSENT 11.4 8.0 24.0 11.4 8.0 24.0 67 PRESENT 12.6 13.0 37.5 11.5 7.7 24.0 68 ABSENT 11.5 7.8 24.2 11.5 7.8 24.2 69 PRESENT 12.6 13.1 37.6 11.6 8.5 24.7 70 ABSENT 11.5 7.7 24.0 11.5 7.7 24.0 71 PRESENT 12.6 13.2 37.5 11.6 8.8 24.9 72 ABSENT 11.4 7.7 24.0 11.4 7.7 24.0 73 ABSENT 11.5 7.8 24.1 11.5 7.8 24.1__________________________________________________________________________ indicates values outside of the conditions of the present invention TABLE 12-1 STARTING MATERIAL COMPOSITION (WEIGHT %) MAGNETIC CHARACTERISTICS R--B--Fe PRIOR TO CORROSION TEST AFTER CORROSION TEST OXIDE POWDERS ALLOY RUST Br iHc BH max Br iHc BH max SAMPLE Y.sub.2 O.sub.3 Ho.sub.2 O.sub.3 Er.sub.2 O.sub.3 Tm.sub.2 O.sub.3 Lu.sub.2 O.sub.3 Eu.sub.2 O.sub.3 TOTAL POWDER STATE (KG) (KOe) (MGOe) (KG) (KOe) (MGOe) EXAMPLES 180 0.0006 -- -- -- -- -- 0.0006 BALANCE ABSENT 12.6 13.8 38.2 12.4 13.5 37.2 181 0.09 -- -- -- -- -- 0.09 BALANCE ABSENT 12.5 14.2 38.2 12.5 14.0 38.0 182 2.4 -- -- -- -- -- 2.4 BALANCE ABSENT 12.4 14.0 37.6 12.4 14.0 37.6 183 -- 0.0006 -- -- -- -- 0.0006 BALANCE ABSENT 12.5 13.5 37.8 12.3 13.1 35.9 184 -- 0.1 -- -- -- -- 0.1 BALANCE ABSENT 12.4 13.9 37.5 12.4 13.7 37.3 185 -- 2.3 -- -- -- -- 2.3 BALANCE ABSENT 12.3 13.7 36.2 12.3 13.7 36.2 186 -- -- 0.0006 -- -- -- 0.0006 BALANCE ABSENT 12.6 13.6 38.0 12.4 13.4 37.0 187 -- -- 0.8 -- -- -- 0.08 BALANCE ABSENT 12.5 13.8 37.9 12.4 13.7 37.6 188 -- -- 2.4 -- -- -- 2.4 BALANCE ABSENT 12.3 13.7 36.5 12.3 13.7 36.5 189 -- -- -- 0.0007 -- -- 0.0007 BALANCE ABSENT 12.6 13.9 38.2 12.4 13.7 37.3 190 -- -- -- 0.1 -- -- 0.1 BALANCE ABSENT 12.5 14.3 38.3 12.5 14.1 38.1 191 -- -- -- 2.3 -- -- 2.3 BALANCE ABSENT 12.3 14.1 36.6 12.3 14.1 36.6 192 -- -- -- -- 0.0006 -- 0.0006 BALANCE ABSENT 12.6 13.8 38.1 12.4 13.5 37.1 193 -- -- -- -- 0.09 -- 0.09 BALANCE ABSENT 12.5 14.0 38.1 12.5 13.9 38.0 194 -- -- -- -- 2.4 -- 2.4 BALANCE ABSENT 12.3 13.9 36.5 12.3 13.9 36.5 195 -- -- -- -- -- 0.0006 0.0006 BALANCE ABSENT 12.6 13.7 38.0 12.4 13.5 37.2 196 -- -- -- -- -- 0.11 0.11 BALANCE ABSENT 12.5 13.5 38.0 12.5 13.7 37.9 197 -- -- -- -- -- 2.4 2.4 BALANCE ABSENT 12.3 13.9 36.4 12.3 13.9 36.4 TABLE 12-2 STARTING MATERIAL COMPOSITION (WEIGHT %) MAGNETIC CHARACTERISTICS R--B--Fe PRIOR TO CORROSION TEST AFTER CORROSION TEST OXID POWDERS ALLOY RUST Br iHc BH max Br iHc BH max SAMPLE Y.sub.2 O.sub.3 Ho.sub.2 O.sub.3 Er.sub.2 O.sub.3 Tm.sub.2 O.sub.3 Lu.sub.2 O.sub.3 Eu.sub.2 O.sub.3 TOTAL POWDER STATE (KG) (KOe) (MGOe) (KG) (KOe) (MGOe) EXAMPLES 198 0.0002 0.0002 -- -- 0.0002 0.0001 0.0007 remainder ABSENT 12.6 13.9 38.2 12.4 13.7 37.5 199 -- 0.1 0.1 -- -- -- 0.2 .uparw. .uparw. 12.4 14.0 37.7 12.4 13.9 37.6 200 -- -- 0.5 0.2 -- -- 0.7 .uparw. .uparw. 12.4 14.1 37.7 12.4 14.0 37.7 201 0.4 -- -- 0.5 -- 0.2 1.1 .uparw. .uparw. 12.4 14.2 37.8 12.4 14.1 37.7 202 1.0 -- 1.0 -- -- 0.2 2.2 .uparw. .uparw. 12.3 14.1 36.6 12.3 14.1 36.6 203 0.5 0.5 -- 0.5 -- 0.5 2.0 .uparw. .uparw. 12.3 14.2 36.7 12.3 14.2 36.7 204 -- 0.2 -- 0.5 -- -- 0.7 .uparw. .uparw. 12.4 14.0 37.6 12.4 13.8 37.5 205 -- -- 0.1 0.2 -- -- 0.3 .uparw. .uparw. 12.4 14.3 37.9 12.4 14.0 37.7 206 -- -- -- -- 0.3 0.7 1.0 .uparw. .uparw. 12.4 14.1 37.7 12.4 14.0 37.7 207 -- 0.01 -- 0.01 -- -- 0.02 .uparw. .uparw. 12.4 13.8 37.5 12.4 13.5 37.4 208 -- 0.2 0.05 -- -- -- 0.205 .uparw. .uparw. 12.4 14.1 37.7 12.4 13.7 37.5 209 -- -- 0.8 -- -- 0.2 1.0 .uparw. .uparw. 12.4 14.0 37.6 12.4 13.9 37.6 210 -- 0.02 -- 0.02 0.02 0.02 0.08 .uparw. .uparw. 12.4 13.9 37.6 12.4 13.7 37.5 211 0.01 -- 0.1 -- -- 0.1 0.21 .uparw. .uparw. 12.4 14.1 37.7 12.4 13.8 37.5 212 -- -- 0.01 0.01 0.01 0.01 0.04 .uparw. .uparw. 12.4 13.9 37.6 12.4 13.7 37.5 213 -- -- 0.2 0.2 0.2 -- 0.6 .uparw. .uparw. 12.4 14.1 37.7 12.4 14.0 37.7 214 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0006 .uparw. .uparw. 12.6 13.8 38.1 12.4 13.4 37.3 215 0.4 0.4 0.4 0.4 0.4 0.4 2.4 .uparw. .uparw. 12.3 14.1 36.6 12.3 14.1 36.6 TABLE 12-3 STARTING MATERIAL COMPOSITION (WEIGHT %) MAGNETIC CHARACTERISTICS R--B--Fe PRIOR TO CORROSION TEST AFTER CORROSION TEST OXID POWDERS ALLOY RUST Br iHc BH max Br iHc BH max SAMPLE Y.sub.2 O.sub.3 Ho.sub.2 O.sub.3 Er.sub.2 O.sub.3 Tm.sub.2 O.sub.3 Lu.sub.2 O.sub.3 Eu.sub.2 O.sub.3 TOTAL POWDER STATE (KG) (KOe) (MGOe) (KG) (KOe) (MGOe) COMPARATIVE EXAMPLES 74 -- -- -- -- -- -- -- 100 heavy 12.5 12.5 36.8 1 1.2 7.5 22.0 75 0.0003 -- -- -- -- -- 0.0003 remainder present 12.6 13.3 37.9 11.7 10.0 25.3 76 3.1 -- -- -- -- -- 3.1 .uparw. absent 11.4 7.6 24.0 11.4 7.6 24.0 77 -- 0.0002 -- -- -- -- 0.0002 .uparw. present 12.5 13.2 37.8 11.4 9.4 25.0 78 -- 3.2 -- -- -- -- 3.2 .uparw. absent 11.4 7.3 23.7 11.4 7.3 23.7 79 -- -- 0.0003 -- -- -- 0.0003 .uparw. present 12.5 13.0 37.5 11.4 9.5 25.1 80 -- -- 3.1 -- -- -- 3.1 .uparw. absent 11.3 7.5 22.3 11.3 7.5 22.9 81 -- -- -- 0.0003 -- -- 0.0003 .uparw. present 12.6 13.3 37.8 11.5 8.7 25.0 82 -- -- -- 3.1 -- -- 3.1 .uparw. absent 11.3 7.6 23.0 11.3 7.6 23.0 83 -- -- -- -- 0.0003 -- 0.0003 .uparw. present 12.6 13.1 37.6 11.4 8.8 24.7 84 -- -- -- -- 3.2 -- 3.2 .uparw. absent 11.4 7.5 24.3 11.4 7.5 24.3 85 -- -- -- -- -- 0.0003 0.0003 .uparw. present 12.6 12.4 37.5 11.5 7.7 24.9 86 -- -- -- -- -- 3.1 3.1 .uparw. absent 11.5 7.4 21.8 11.5 7.4 21.8 87 0.0001 0.0001 0.0001 -- -- -- 0.0003 .uparw. present 12.6 13.0 37.7 11.5 7.9 24.6 88 0.5 0.5 0.5 0.5 0.5 0.6 3.1 .uparw. absent 11.4 7.2 23.3 11.4 7.2 23.3 89 -- 1.5 -- 1.7 -- -- 3.2 .uparw. absent 11.4 7.7 24.1 11.4 7.7 24.1 TABLE 13-1 COMPOSITION OF THE POWDER (WEIGHT %) MAGNETIC PROPERTIES Cr.sub.2 O.sub.3 NITRIDE POWDERS R--B--Fe* Before Corrosion Test After Corrosion Test POW- TO- ALLOY RUST Br iHc BH max Br iHc BH max SAMPLE DER CrN MnN.sub.4 ZrN HfN TiN NbN Ni.sub.2 N Si.sub.3 N.sub.4 GeN VN GaN AlN Co.sub.3 N TAL POWDER STATE (KG) (KOe) (MGOe) (KG) (KOe) (MGOe) EXAMPLES 216 0.0005 3.0 -- -- -- -- -- -- -- -- -- -- -- -- 3.0 remainder absent 12.6 14.0 38.5 12.5 13.8 38.2 217 0.05 2.0 -- -- -- -- -- -- -- -- -- -- -- -- 2.0 .uparw. .uparw. 12.6 14.0 38.5 12.6 13.8 38.4 218 0.5 1.0 -- -- -- -- -- -- -- -- -- -- -- -- 1.0 .uparw. .uparw. 12.5 13.8 38.2 12.5 13.8 38.2 219 1.5 0.05 -- -- -- -- -- -- -- -- -- -- -- -- 0.05 .uparw. .uparw. 12.5 13.7 38.2 12.5 13.7 38.2 220 2.5 0.0006 -- -- -- -- -- -- -- -- -- -- -- -- 0.006 .uparw. .uparw. 12.4 13.0 36.2 12.4 13.0 36.2 221 0.0006 -- 3.0 -- -- -- -- -- -- -- -- -- -- -- 3.0 .uparw. .uparw. 12.5 14.0 38.3 12.5 13.8 38.2 222 0.05 -- 2.0 -- -- -- -- -- -- -- -- -- -- -- 2.0 .uparw. .uparw. 12.5 13.8 38.2 12.5 13.8 38.2 223 0.5 -- 1.0 -- -- -- -- -- -- -- -- -- -- -- 1.0 .uparw. .uparw. 12.4 13.6 36.5 12.4 13.6 36.5 224 1.5 -- 0.05 -- -- -- -- -- -- -- -- -- -- -- 0.05 .uparw. .uparw. 12.3 13.5 36.3 12.3 13.5 36.3 225 2.5 -- 0.0005 -- -- -- -- -- -- -- -- -- -- -- 0.0005 .uparw. .uparw. 12.3 13.1 36.2 12.3 13.0 36.2 226 0.0005 -- -- 3.0 -- -- -- -- -- -- -- -- -- -- 3.0 .uparw. .uparw. 12.6 14.1 38.5 12.5 13.8 38.2 227 0.05 -- -- 2.1 -- -- -- -- -- -- -- -- -- -- 2.1 .uparw. .uparw. 12.6 14.0 38.5 12.6 13.9 38.5 228 0.5 -- -- 1.5 -- -- -- -- -- -- -- -- -- -- 1.5 .uparw. .uparw. 12.5 14.0 38.3 12.5 14.0 38.3 229 1.5 -- -- 0.03 -- -- -- -- -- -- -- -- -- -- 0.03 .uparw. .uparw. 12.5 13.7 38.2 12.5 13.7 38.2 230 2.5 -- -- 0.0007 -- -- -- -- -- -- -- -- -- -- 0.0007 .uparw. .uparw. 12.4 13.2 36.3 12.4 13.2 36.3 231 0.0006 -- -- -- 2.1 -- -- -- -- -- -- -- -- -- 2.1 .uparw. .uparw. 12.5 13.8 38.2 12.5 13.7 38.1 232 0.06 -- -- -- 2.9 -- -- -- -- -- -- -- -- -- 2.9 .uparw. .uparw. 12.6 14.0 38.5 12.6 13.9 38.4 233 0.6 -- -- -- 1.6 -- -- -- -- -- -- -- -- -- 1.6 .uparw. .uparw. 12.5 13.7 38.2 12.5 13.7 38.2 234 1.7 -- -- -- 0.05 -- -- -- -- -- -- -- -- -- 0.05 .uparw. .uparw. 12.4 13.6 36.5 12.4 13.6 36.5 *Alloy Formed from Nd15%, B8%, Feremainder (here % is atomic %) TABLE 13-2 MAGNETIC PROPERTIES COMPOSITION OF THE POWDER (WEIGHT %) Before After R --B--Fe* Corrosion Test Corrosion Test SAM- Cr.sub.2 O.sub.3 NITRIDE POWDERS ALLOY RUST Br iHe BH max Br iHe BH max PLE POWDER CrN MnN.sub.6 ZrN HfN TiN NbN Ni.sub.2 N Si.sub.3 N.sub.6 GeN VN GaN AlN Co.sub.3 N TOTAL POWDER STATE (KG) (KOe) (MGOe) (KG) (KOe) (MGOe) EXAMPLES 235 2.4 ---- --0.0005 -- -- -- -- ---- -- -- -- 0.0005 remainder absent 12.5 13.8 38.0 12.5 13.8 38.0 236 2.5 ---- ---- 1.5 -- -- -- -- -- -- -- -- 1.5 .uparw. .uparw. 12.5 14.0 38.3 12.5 14.0 38.2 237 2.0 ---- ---- 3.0 -- -- -- ----- -- -- -- 3.0 .uparw. .uparw. 12.4 13.7 36.5 12.4 13.7 36.5 238 1.0 ---- ---- 2.0 -- -- -- ---- -- -- -- 2.0 .uparw. .uparw. 12.4 13.7 36.5 12.4 13.7 36.5 239 0.5 ---- ---- 0.06 -- -- -- ---- -- -- -- 0.06 .uparw. .uparw. 12.4 13.8 36.6 12.4 13.6 36.5 240 0.0005 ---- ---- 0.0006 -- -- -- ---- -- -- -- 0.0006 .uparw. .uparw. 12.5 14.0 38.3 12.4 13.7 37.8 241 0.0006 ---- ---- -- 0.0006 -- -- ---- -- -- -- 0.0006 .uparw. .uparw. 12.6 13.7 38.4 12.5 13.5 38.0 242 0.1 ---- ---- -- 0.02 -- -- ---- -- -- -- 0.02 .uparw. .uparw. 12.7 14.0 38.8 12.7 13.9 38.7 243 1.0 ---- ---- -- 1.0 -- -- ---- -- -- -- 1.0 .uparw. .uparw. 12.7 14.0 38.8 12.7 14.0 38.8 244 1.7 ---- ---- -- 2.0 -- -- ---- -- -- -- 2.0 .uparw. .uparw. 12.6 13.5 38.3 12.6 13.5 38.3 245 2.4 ---- ---- -- 2.9 -- -- ---- -- -- -- 2.9 .uparw. .uparw. 12.5 13.0 37.5 12.5 12.9 37.4 246 0.0006 ---- ---- -- -- 0.0006 -- ---- -- -- -- 0.0006 .uparw. .uparw. 12.5 14.1 38.3 12.4 13.8 38.0 247 0.08 ---- ---- -- -- 1.5 -- ---- -- -- -- 1.5 .uparw. .uparw. 12.5 14.2 38.4 12.4 14.0 38.2 248 0.5 ---- ---- -- -- 0.03 -- ---- -- -- -- 0.03 .uparw. .uparw. 12.5 14.0 38.3 12.5 14.0 38.3 249 1.3 ---- ---- -- -- 0.4 -- ---- -- -- -- 0.4 .uparw. .uparw. 12.4 14.0 36.7 12.4 14.0 36.8 250 2.3 ---- ---- -- -- 2.8 -- ---- -- -- -- 2.5 .uparw. .uparw. 12.3 13.8 35.8 12.3 13.7 35.6 251 0.0005 ---- ---- -- -- -- 3.0 ---- -- -- -- 3.0 .uparw. .uparw. 12.2 13.8 35.0 12.2 13.8 35.0 252 0.08 ---- ---- -- -- -- 1.9 ---- -- -- -- 1.9 .uparw. .uparw. 12.4 14.1 36.8 12.4 14.0 36.7 253 1.0 ---- ---- -- -- -- 1.0 ---- -- -- -- 1.0 .uparw. .uparw. 12.7 13.9 38.7 12.7 13.9 38.7 *Alloy formed from Nd15%, B8%, Feremainder (here % is atomic %) TABLE 13-3 MAGNETIC PROPERTIES COMPOSITION OF THE POWDER (WEIGHT %) Before After C r.sub.2 O.sub.3 R--B--Fe* Corrosion Test Corrosion Test SAM- POW- NITRIDE POWDERS ALLOY RUST Br iHe BH max Br iHe BH max PLE DER CrN MnN.sub.4 ZrN HfN TiN NbN Ni.sub.2 N Si.sub.3 N.sub.4 GeN VN GaN AlN Co.sub.3 N TOTAL POWDER STATE (KG) (KOe) (MGOe) (KG) (KOe) (MGOe) EXAMPLES 254 1.5 -- -- -- -- -- -- -- 0.06 -- -- -- -- -- 0.06 remainder absent 12.6 13.7 38.3 12.6 13.7 38.3 255 2.5 -- -- -- -- -- -- -- 0.0005 -- -- -- -- -- 0.0005 .uparw. .uparw. 12.5 13.7 38.2 12.5 13.6 38.1 256 0.0007 -- -- -- -- -- -- -- -- 0.01 -- -- -- -- 0.01 .uparw. .uparw. 12.5 13.5 38.0 12.5 13.3 37.8 257 0.01 -- -- -- -- -- -- -- -- 1.0 -- -- -- -- 1.0 .uparw. .uparw. 12.5 13.7 38.2 12.5 13.6 38.0 258 0.1 -- -- -- -- -- -- -- -- 0.0005 -- -- -- -- 0.0005 .uparw. .uparw. 12.5 13.4 37.9 12.4 13.3 37.8 259 1.0 -- -- -- -- -- -- -- -- 3.0 -- -- -- -- 3.0 .uparw. .uparw. 12.5 13.8 38.5 12.5 13.8 38.5 260 2.2 -- -- -- -- -- -- -- -- 2.0 -- -- -- -- 2.0 .uparw. .uparw. 12.4 13.7 36.4 12.4 13.7 36.4 261 0.0005 -- -- -- -- -- -- -- -- -- 2.9 -- -- -- 2.9 .uparw. .uparw. 12.5 13.8 38.4 12.5 13.5 38.1 262 0.07 -- -- -- -- -- -- -- -- -- 1.9 -- -- -- 1.9 .uparw. .uparw. 12.5 13.7 38.3 12.5 13.5 38.1 263 1.0 -- -- -- -- -- -- -- -- -- 1.1 -- -- -- 1.1 .uparw. .uparw. 12.5 13.8 38.4 12.5 13.8 38.4 264 1.5 -- -- -- -- -- -- -- -- -- 0.01 -- -- -- 0.01 .uparw. .uparw. 12.5 13.6 38.1 12.5 13.5 38.1 265 2.5 -- -- -- -- -- -- -- -- -- 0.0005 -- -- -- 0.0005 .uparw. .uparw. 12.5 13.7 38.2 12.5 13.4 37.9 266 0.0005 -- -- -- -- -- -- -- -- -- -- 2.0 -- -- 2.0 .uparw. .uparw. 12.5 14.3 38.5 12.5 14.2 38.4 267 0.05 -- -- -- -- -- -- -- -- -- -- 2.9 -- -- 2.9 .uparw. .uparw. 12.5 14.5 38.7 12.5 14.4 38.6 268 1.0 -- -- -- -- -- -- -- -- -- -- 1.3 -- -- 1.3 .uparw. .uparw. 12.5 14.1 38.3 12.5 14.1 38.3 269 1.6 -- -- -- -- -- -- -- -- -- -- 0.1 -- -- 0.1 .uparw. .uparw. 12.5 14.0 38.3 12.5 14.0 38.3 270 2.5 -- -- -- -- -- -- -- -- -- -- 0.0005 -- -- 0.0005 .uparw. .uparw. 12.4 13.9 36.5 12.4 13.7 36.3 271 0.0006 -- -- -- -- -- -- -- -- -- -- -- 3.0 -- 3.0 .uparw. .uparw. 12.4 14.7 38.0 12.4 14.6 37.9 272 0.09 -- -- -- -- -- -- -- -- -- -- -- 2.1 -- 2.1 .uparw. .uparw. 12.4 14.5 37.8 12.4 14.4 37.8 *Alloy formed from Nd15%, B8%, Feremainder (here % is atomic %) TABLE 13-4 MAGNETIC PROPERTIES COMPOSITION OF THE POWDER (WEIGHT %) Before After R--B--Fe* Corrosion Test Corrosion Test SAM- Cr.sub.2 O.sub.3 NITRIDE POWDERS ALLOY RUST Br iHe BH max Br iHe BH max PLE POWDER CrN MnN.sub.4 ZrN HfN TiN NbN Ni.sub.2 N Si.sub.3 N.sub.4 GeN VN GaN AlN Co.sub.3 N TOTAL POWDER STATE (KG) (KOe) (MGOe) (KG) (KOe) (MGOe) EXAMPLES 273 1.0 -- -- -- -- -- -- -- -- -- -- -- 1.0 -- 1.0 remainder absent 12.4 14.3 37.6 12.4 14.2 37.5 274 1.8 -- -- -- -- -- -- -- -- -- -- -- 0.08 -- 0.08 .uparw. .uparw. 12.4 14.1 37.4 12.4 13.9 37.2 275 2.5 -- -- -- -- -- -- -- -- -- -- -- 0.0005 -- 0.0005 .uparw. .uparw. 12.4 13.8 36.5 12.4 13.6 36.3 276 0.0005 -- -- -- -- -- -- -- -- -- -- -- -- 3.0 3.0 .uparw. .uparw. 12.4 13.6 36.3 12.4 13.4 36.1 277 0.01 -- -- -- -- -- -- -- -- -- -- -- -- 2.0 2.0 .uparw. .uparw. 12.5 13.5 38.0 12.5 13.4 37.9 278 0.1 -- -- -- -- -- -- -- -- -- -- -- -- 1.0 1.0 .uparw. .uparw. 12.5 13.6 38.1 12.5 13.4 37.9 279 1.3 -- -- -- -- -- -- -- -- -- -- -- -- 0.08 0.08 .uparw. .uparw. 12.4 13.6 36.3 12.4 13.4 36.1 280 2.5 -- -- -- -- -- -- -- -- -- -- ---- 0.0005 0.0005 .uparw. .uparw. 12.3 13.7 35.7 12.3 13.6 35.9 281 1.2 0.1 0.1 -- -- -- -- -- -- -- -- -- -- -- 0.2 .uparw. .uparw. 12.4 13.6 36.3 12.4 13.5 36.2 282 1.2 0.4 0.1 0.4 -- -- -- -- -- -- -- -- -- -- 0.9 .uparw. .uparw. 12.4 13.5 36.2 12.4 13.3 36.0 283 1.2 0.7 0.7 0.1 0.1 -- -- -- -- -- -- -- -- -- 1.6 .uparw. .uparw. 12.4 13.6 36.3 12.4 13.5 36.2 284 1.2 0.1 0.1 0.1 0.1 0.1 -- -- -- -- -- -- -- -- 0.5 .uparw. .uparw. 12.5 13.4 37.9 12.5 13.3 38.0 285 1.2 0.5 -- 0.3 -- -- 0.1 0.5 -- -- -- -- 0.5 -- 1.9 .uparw. .uparw. 12.4 13.5 36.2 12.4 13.5 36.2 286 1.2 0.7 -- -- -- -- -- 0.8 -- -- -- -- 0.6 0.5 2.6 .uparw. .uparw. 12.4 13.4 36.1 12.4 13.4 36.1 287 1.2 0.7 -- -- -- 0.3 -- 0.5 0.3 -- -- -- 0.6 0.5 2.9 .uparw. .uparw. 12.3 14.0 36.0 12.3 13.9 35.9 288 1.8 -- 0.6 0.3 -- -- -- -- 0.2 -- 0.5 0.4 -- -- 2.0 .uparw. .uparw. 12.3 13.9 35.9 12.3 13.9 35.9 289 1.8 -- -- -- -- -- 0.3 -- -- 0.3 -- -- -- -- 0.6 .uparw. .uparw. 12.4 13.6 36.3 12.4 13.5 36.2 290 1.8 -- -- -- -- 0.01 -- 0.01 -- 0.01 0.01 -- 0.01 -- 0.05 .uparw. .uparw. 12.4 14.0 37.3 12.4 14.0 37.3 291 1.8 0.01 -- 0.03 -- 0.01 -- 0.01 -- 0.01 -- 0.01 -- 0.01 0.09 .uparw. .uparw. 12.4 13.7 36.4 12.4 13.5 36.2 *Alloy formed from Nd15%, B8%, Feremainder (here % is atomic %) TABLE 13-5 MAGNETIC PROPERTIES COMPOSITION OF THE POWDER (WEIGHT %) Before After C r.sub.2 O.sub.3 R--B--Fe* Corrosion Test Corrosion Test SAM- POW- NITRIDE POWDERS ALLOY RUST BriHe BH max BriHe BH max PLEDER CrN MnN.sub.4 ZrN HfN TiN NbN Ni.sub.2 N Si.sub.3 N.sub.4 GeN VN GaN AlN Co.sub.3 N TOTAL POWDER STATE (KG) (KOe) (MGOe) (KG) (KOe) (MGOe) EXAMPLES 2921.8 -- 0.01 -- 0.01 -- 0.01 --0.01 -- 0.01 -- 0.01 --0.06 remainder A 12.513.4 37.9 12.513.3 37.8 2930.5 0.001 0.001 0.001 0.001 0.001 0.001 0.0010.001 0.001 0.001 0.001 0.001 0.0010.013 .uparw. .uparw. 12.613.6 38.3 12.613.3 38.0 2940.5 0.01 -- -- 0.01 -- -- 0.01-- -- 0.01 -- -- 0.010.05 .uparw. .uparw. 12.513.0 37.5 12.512.9 37.4 2950.5 -- 0.01 -- -- 0.01 -- --0.01 -- -- 0.01 -- --0.04 .uparw. .uparw. 12.513.5 38.0 12.513.3 37.8 2960.5 -- -- 0.03 -- -- 0.03 ---- 0.03 -- -- 0.03 --0.12 .uparw. .uparw. 12.413.9 36.5 12.413.9 36.5 2970.5 -- -- -- 0.2 -- -- 0.2-- -- 0.2 -- -- 0.20.8 .uparw. .uparw. 12.413.6 36.3 12.413.5 36.2 2980.5 1.3 -- -- -- 0.04 -- ---- 0.03 -- -- 0.02 --1.39 .uparw. .uparw. 12.413.8 36.5 1 12.43.8 36.5 2990.07 -- 0.9 -- -- -- -- 0.9-- -- -- -- 0.9 --2.7 .uparw. .uparw. 12.314.0 36.0 12.313.9 35.9 3000.07 -- -- -- 0.1 -- -- ---- 1.1 -- 0.1 -- --1.3 .uparw. .uparw. 12.513.6 38.1 12.513.4 37.9 COMPARATIVE EXAMPLES 900.0002 0.5 -- -- -- -- -- ---- -- -- -- -- --0.5 .uparw. P 12.513.8 38.2 11.86.1 22.5 913.1 0.5 -- -- -- -- -- ---- -- -- -- -- --0.5 .uparw. A 11.17.2 23.5 11.17.2 23.5 921.3 0.0002 -- -- -- -- -- ---- -- -- -- -- --0.0002 .uparw. P 12.513.7 38.1 11.45.9 22.3 931.3 3.2 -- -- -- -- -- ---- -- -- -- -- --3.2 .uparw. A 11.57.5 24.1 11.57.5 24.1 941.3 -- 0.0002 -- -- -- -- ---- -- -- -- -- --0.0002 .uparw. P 12.513.5 37.9 10.94.2 19.2 951.3 -- 3.3 -- -- -- -- ---- -- -- -- -- --3.3 .uparw. A 11.07.8 20.2 11.07.7 20.0 961.3 -- -- 0.0003 -- -- -- ---- -- -- -- -- --0.0003 .uparw. P 12.513.1 37.6 11.04.5 22.0 971.3 -- -- 3.2 -- -- -- ---- -- -- -- -- --3.2 .uparw. A 10.35.6 19.1 10.35.6 10.3 981.3 -- -- -- 0.0001 -- -- ---- -- -- -- -- --0.0001 .uparw. P 12.513.2 37.8 11.04.2 20.8 991.3 -- -- -- 3.3 -- -- ---- -- -- -- -- --3.3 .uparw. A 10.36.5 19.9 10.36.5 19.9 *Alloy formed from Nd15%, B8%, Feremainder (here % is atomic %) A is absent, P is present indicates values outside of the range of the present invention TABLE 13-6 COMPOSITION OF THE POWDER (WEIGHT %) R--B--Fe* Cr.sub.2 O.sub.3 NITRIDE POWDERS ALLOY SAMPLE POWDER CrN MnN.sub.4 ZrN HfN TiN NbN Ni.sub.2 N Si.sub.3 N.sub.4 GeN VN GaN AlN Co.sub.3 N TOTAL POWDER COMPARATIVE EXAMPLES 100 1.3 -- -- -- -- 0.0003 -- -- -- -- -- -- -- -- 0.0003 remainder 101 1.3 -- -- -- -- 3.2 -- -- -- -- -- -- -- -- 3.2 .uparw. 102 1.3 -- -- -- -- -- 0.0002 -- -- -- -- -- -- -- 0.0002 .uparw. 103 1.3 -- -- -- -- -- 3.3 -- -- -- -- -- -- -- 3.3 .uparw. 104 1.3 -- -- -- -- -- -- 0.0003 -- -- -- -- -- -- 0.0003 .uparw. 105 1.3 -- -- -- -- -- -- 3.2 -- -- -- -- -- -- 3.2 .uparw. 106 1.3 -- -- -- -- -- -- -- 0.0002 -- -- -- -- -- 0.0002 .uparw. 107 1.3 -- -- -- -- -- -- -- 3.3 -- -- -- -- -- 3.3 .uparw. 108 1.3 -- -- -- -- -- -- -- -- 0.0003 -- -- -- -- 0.0003 .uparw. 109 1.3 -- -- -- -- -- -- -- -- 3.2 -- -- -- -- 3.2 .uparw. 110 1.3 -- -- -- -- -- -- -- -- -- 0.0002 -- -- -- 0.0002 .uparw. 111 1.3 -- -- -- -- -- -- -- -- -- 3.3 -- -- -- 3.3 .uparw. 112 1.3 -- -- -- -- -- -- -- -- -- -- 0.0001 -- -- 0.0001 .uparw. 113 1.3 -- -- -- -- -- -- -- -- -- -- 3.2 -- -- 3.2 .uparw. 114 1.3 -- -- -- -- -- -- -- -- -- -- -- 0.0002 -- 0.0002 .uparw. 115 1.3 -- -- -- -- -- -- -- -- -- -- -- 3.3 -- 3.3 .uparw. 116 1.3 -- -- -- -- -- -- -- -- -- -- -- -- 0.0003 0.0003 .uparw. 117 1.3 -- -- -- -- -- -- -- -- -- -- -- -- 3.2 3.2 .uparw. 118 -- 0.5 0.5 -- -- 0.5 -- -- -- -- -- -- -- -- 1.5 .uparw. 119 1.3 0.5 0.5 -- -- 0.5 -- 0.5 0.5 -- 0.5 -- 0.5 -- 3.5 .uparw. MAGNETIC PROPERTIES Before Corrosion Test After Corrosion Test SAMPLE RUST STATE Br (KG) iHe (KOe) BH max (MGOe) Br (KG) i He (KOe) BH max (MGOe) COMPARATIVE EXAMPLES 100 P 12.6 12.8 38.0 10.5 3.0 13.2 101 A 11.5 5.8 22.1 11.5 5.8 22.1 102 P 12.5 13.6 38.0 10.4 5.5 11.8 103 A 11.1 6.5 20.8 11.1 6.5 20.8 104 P 12.5 13.1 37.6 10.6 5.6 18.1 105 A 11.3 7.0 22.0 11.3 7.0 22.0 106 P 12.5 13.3 37.8 10.8 4.3 20.4 107 A 10.9 4.3 18.8 10.9 4.3 20.8 108 P 12.5 13.1 37.6 10.5 5.5 17.8 109 A 10.8 4.5 19.0 10.8 4.5 19.0 110 P 12.5 13.7 38.1 10.5 5.9 18.0 111 A 10.8 4.8 21.1 10.8 4.8 21.1 112 P 12.5 13.6 38.0 10.4 5.4 11.5 113 A 10.9 6.1 21.0 10.9 6.1 21.0 114 P 12.5 13.5 37.9 10.4 5.0 11.0 115 A 10.7 6.1 20.8 10.7 6.1 20.8 116 P 12.4 12.9 36.1 10.9 4.0 18.0 117 A 10.8 4.6 19.3 10.8 4.6 19.3 118 P 12.4 12.5 36.0 10.9 4.5 21.7 119 A 10.7 5.5 19.8 10.7 5.5 19.8 *Alloy formed from Nd15%, B8%, Feremainder (here % is atomic %) A is absent, P is present indicates values outside of the range of the present invention TABLE 14-1 MAGNETIC PROPERTIES COMPOSITION OF THE POWDER (WEIGHT %) Before After N iO R--B--Fe* Corrosion Test Corrosion Test SAM- POW- NITRIDE POWDERS ALLOY RUST Br iHe BH max Br iHe BH max PLE DER CrN MnN.sub.4 ZrN HfN TiN N bN Ni.sub.2 N Si.sub.3 N.sub.4 GeN VN GaN AlN Co.sub.3 N TOTAL POWDER STATE (KG) (KOe) (MGOe) (KG) (KOe) (MGOe) EXAMPLES 301 0.0006 2.9 -- -- -- -- -- -- -- -- -- -- -- -- 2.9 remainder absent 12.2 21.8 35.5 12.2 21.6 35.4 302 0.01 2.0 -- -- -- -- -- -- -- -- -- -- -- -- 2.0 .uparw. .uparw. 12.2 21.5 35.2 12.2 21.4 35.1 303 0.1 1.0 -- -- -- -- -- -- -- -- -- -- -- -- 1.0 .uparw. .uparw. 12.3 21.8 36.4 12.2 21.5 36.0 304 1.3 0.01 -- -- -- -- -- -- -- -- -- -- -- -- 0.01 .uparw. .uparw. 12.2 21.6 35.3 12.2 21.5 35.2 305 2.5 0.0005 -- -- -- -- -- -- -- -- -- -- -- -- 0.005 .uparw. .uparw. 12.2 21.4 35.1 12.2 21.3 35.0 306 0.0005 -- 1.0 -- -- -- -- -- -- -- -- -- -- -- 1.0 .uparw. .uparw. 12.2 21.6 35.3 12.2 12.4 35.1 307 0.05 -- 2.8 -- -- -- -- -- -- -- -- -- -- -- 2.8 .uparw. .uparw. 12.3 21.8 36.4 12.2 21.7 35.4 308 0.5 -- 2.1 -- -- -- -- -- -- -- -- -- -- -- 2.1 .uparw. .uparw. 12.3 21.7 36.3 12.2 21.5 35.2 309 1.4 -- 0.05 -- -- -- -- -- -- -- -- -- -- -- 0.05 .uparw. .uparw. 12.2 21.8 35.5 12.2 21.7 35.4 310 2.4 -- 0.0006 -- -- -- -- -- -- -- -- -- -- -- 0.0006 .uparw. .uparw. 12.2 21.5 35.2 12.2 21.2 35.0 311 0.0006 -- -- 2.1 -- -- -- -- -- -- -- -- -- -- 2.1 .uparw. .uparw. 12.3 21.4 36.0 12.2 21.2 35.0 312 0.009 -- -- 3.0 -- -- -- -- -- -- -- -- -- -- 3.0 .uparw. .uparw. 12.3 21.5 36.1 12.2 21.3 35.1 313 0.1 -- -- 1.0 -- -- -- -- -- -- -- -- -- -- 1.0 .uparw. .uparw. 12.2 21.3 35.1 12.2 21.2 35.0 314 1.6 -- -- 0.06 -- -- -- -- -- -- -- -- -- -- 0.06 .uparw. .uparw. 12.2 21.2 35.0 12.2 21.0 34.8 315 2.4 -- -- 0.0007 -- -- -- -- -- -- -- -- -- -- 0.0007 .uparw. .uparw. 12.2 21.3 35.1 12.2 21.1 34.9 316 0.0007 -- -- -- 1.1 -- -- -- -- -- -- -- -- -- 1.1 .uparw. .uparw. 12.3 21.6 36.2 12.2 21.5 35.3 317 0.01 -- -- -- 3.0 -- -- -- -- -- -- -- -- -- 3.0 .uparw. .uparw. 12.3 21.8 36.4 12.2 21.2 35.0 318 0.5 -- -- -- 2.3 -- -- -- -- -- -- -- -- -- 2.3 .uparw. .uparw. 12.2 21.5 35.2 12.2 21.3 35.0 319 1.5 -- -- -- 0.1 -- -- -- -- -- -- -- -- -- 0.1 .uparw. .uparw. 12.2 21.5 35.2 12.2 21.1 35.0 *Alloy formed from Nd13.5%, Dy1.5%, B8%, Feremainder (here % is atomic %) TABLE 14-2 MAGNETIC PROPERTIES COMPOSITION OF THE POWDER (WEIGHT %) Before After N iO R--B--Fe* Corrosion Test Corrosion Test SAM- POW- NITRIDE POWDERS ALLOY RUST Br iHe BH max Br iHe BH max PLE DER CrN MnN.sub.4 ZrN HfN TiN N bN Ni.sub.2 N Si.sub.3 N.sub.4 GeN VN GaN AlN Co.sub.3 N POWDER STATE (KG) (KOe) (MGOe) (KG) (KOe) (MGOe) EXAMPLES 320 2.3 -- -- -- 0.0006 -- -- -- -- -- -- -- -- -- 0.0006 remainder absent 12.1 20.8 35.0 12.1 20.8 35.0 321 0.0005 -- -- -- -- 0.05 -- -- -- -- -- -- -- -- 0.05 .uparw. .uparw. 12.2 21.3 35.3 12.1 20.7 34.8 322 0.05 -- -- -- -- 2.8 -- -- -- -- -- -- -- -- 2.4 .uparw. .uparw. 12.2 21.6 35.5 12.2 21.3 35.3 323 0.5 -- -- -- -- 1.4 -- -- -- -- -- -- -- -- 1.4 .uparw. .uparw. 12.1 21.8 35.3 12.1 21.5 35.2 324 1.3 -- -- -- -- 0.4 -- -- -- -- -- -- -- -- 0.4 .uparw. .uparw. 12.1 21.5 35.2 12.1 21.5 35.2 325 2.4 -- -- -- -- 0.0005 -- -- -- -- -- -- -- -- 0.0005 .uparw. .uparw. 12.0 20.5 34.8 12.0 20.5 34.8 326 0.0005 -- -- -- -- -- 3.0 -- -- -- -- -- -- -- 3.0 .uparw. .uparw. 12.1 21.8 35.6 12.1 21.5 35.2 327 0.05 -- -- -- -- -- 1.5 -- -- -- -- -- -- -- 1.5 .uparw. .uparw. 12.1 21.6 35.3 12.1 21.5 35.2 328 0.5 -- -- -- -- -- 0.6 -- -- -- -- -- -- -- 0.6 .uparw. .uparw. 12.2 21.6 35.5 12.2 21.5 35.5 329 1.5 -- -- -- -- -- 0.005 -- -- -- -- -- -- -- 0.005 .uparw. .uparw. 12.2 21.5 35.5 12.2 21.3 35.4 330 2.5 -- -- -- -- -- 0.0005 -- -- -- -- -- -- -- 0.0005 .uparw. .uparw. 12.2 21.5 35.5 12.2 21.2 35.2 331 0.0005 -- -- -- -- -- -- 1.5 -- -- -- -- -- -- 1.5 .uparw. .uparw. 12.2 21.3 35.4 12.2 21.2 35.3 332 0.05 -- -- -- -- -- -- 2.9 -- -- -- -- -- -- 2.9 .uparw. .uparw. 12.2 21.2 35.2 12.2 21.0 35.0 333 0.6 -- -- -- -- -- -- 0.6 -- -- -- -- -- -- 0.6 .uparw. .uparw. 12.2 21.6 35.5 12.2 21.4 35.4 334 1.5 -- -- -- -- -- -- 0.05 -- -- -- -- -- -- 0.05 .uparw. .uparw. 12.2 21.5 35.5 12.2 21.3 35.3 335 2.4 -- -- -- -- -- -- 0.0007 -- -- -- -- -- -- 0.0007 .uparw. .uparw. 12.2 21.5 35.5 12.1 21.3 35.3 336 0.0005 -- -- -- -- -- -- -- 3.0 -- -- -- -- -- 3.0 .uparw. .uparw. 12.1 21.4 35.2 12.1 21.3 35.1 337 0.05 -- -- -- -- -- -- -- 1.5 -- -- -- -- -- 1.5 .uparw. .uparw. 12.1 21.3 35.1 12.1 21.2 35.0 338 0.5 -- -- -- -- -- -- -- 0.5 -- -- -- -- -- 0.5 .uparw. .uparw. 12.1 21.2 35.0 12.1 21.1 35.0 *Alloy formed from Nd13.5%, Dy1.5%, B8%, Feremainder (here % is atomic %) TABLE 14-3 COMPOSITION OF THE POWDER (WEIGHT %) MAGNETICAL PROPERTIES NiO NITRIDE POWDERS R--B--Fe* Before Corrosion Test After Corrosion Test SAM- POW- TO- ALLOY RUST Br iHc BH max Br iHc BH max PLE DER CrN MnN.sub.4 ZrN HfN TiN NbN Ni.sub.2 N Si.sub.3 N.sub.4 GeN VN GaN AlN Co.sub.3 N TAL POWDER STATE (KG) (KOe) (MGOe) (KG) (KOe) (MGOe) EXAMPLES 339 1.3 -- -- -- -- -- -- -- 0.03 -- -- -- -- -- 0.03 remainder absent 12.1 21.3 35.1 12.1 21.1 35.0 340 2.5 -- -- -- -- -- -- -- 0.00006 -- -- -- -- -- 0.0006 .uparw. .uparw. 12.1 21.3 35.1 12.1 21.2 35.0 341 0.0005 -- -- -- -- -- -- -- -- 0.5 -- -- -- -- 0.5 .uparw. .uparw. 12.2 21.2 35.2 12.1 21.0 34.9 342 0.05 -- -- -- -- -- -- -- -- 3.0 -- -- -- -- 3.0 .uparw. .uparw. 12.2 21.1 35.1 12.2 21.0 35.0 343 0.5 -- -- -- -- -- -- -- -- 2.1 -- -- -- -- 2.1 .uparw. .uparw. 12.2 21.0 35.0 12.2 21.0 35.0 344 1.4 -- -- -- -- -- -- -- -- 1.3 -- -- -- -- 1.3 .uparw. .uparw. 12.2 21.0 35.0 12.1 20.9 34.8 345 2.5 -- -- -- -- -- -- -- -- 0.0006 -- -- -- -- 0.0006 .uparw. .uparw. 12.1 21.2 35.2 12.1 21.0 34.9 346 0.0006 -- -- -- -- -- -- -- -- -- 3.0 -- -- -- 3.0 .uparw. .uparw. 12.2 22.0 36.1 12.2 21.8 36.0 347 0.04 -- -- -- -- -- -- -- -- -- 2.0 -- -- -- 2.0 .uparw. .uparw. 12.2 21.8 35.7 12.2 21.6 35.3 348 0.5 -- -- -- -- -- -- -- -- -- 1.0 -- -- -- 1.0 .uparw. .uparw. 12.3 22.0 36.2 12.3 21.8 36.0 349 1.3 -- -- -- -- -- -- -- -- -- 0.05 -- -- -- 0.05 .uparw. .uparw. 12.2 22.3 36.1 12.2 22.2 36.1 350 2.4 -- -- -- -- -- -- -- -- -- 0.0005 -- -- --0.0005 .uparw. .uparw. 12.1 20.5 34.7 12.1 20.5 34.7 351 0.0005 -- -- -- -- -- -- -- -- -- -- 1.7 -- -- 1.7 .uparw. .uparw. 12.2 22.1 36.1 12.1 21.5 35.2 352 0.07 -- -- -- -- -- -- -- -- -- -- 2.9 -- --2.9 .uparw. .uparw. 12.2 22.5 36.4 12.2 22.2 36.0 353 1.1 -- -- -- -- -- -- -- -- -- -- 0.01 -- -- 0.01 .uparw. .uparw. 12.2 22.0 36.1 12.1 21.8 35.5 354 1.8 -- -- -- -- -- -- -- -- -- -- 0.2 -- -- 0.2 .uparw. .uparw. 12.2 22.0 36.1 12.2 21.5 35.5 355 2.3 -- -- -- -- -- -- -- -- -- -- 0.0005 -- -- 0.0005 .uparw. .uparw. 12.2 21.3 35.4 12.1 21.0 34.9 356 0.0005 -- -- -- -- -- -- -- -- -- -- -- 2.8 -- 2.8 .uparw. .uparw. 12.2 21.8 35.5 12.1 21.0 34.9 357 0.05 -- -- -- -- -- -- -- -- -- -- -- 1.6 -- 1.6 .uparw. .uparw. 12.2 22.0 35.7 12.1 22.0 35.2 *Alloy formed from Nd13.5%, Dy1.5%, B8%, Feremainder (here % is atomic %) TABLE 14-4 COMPOSITION OF THE POWDER (WEIGHT %) MAGNETICAL PROPERTIES NITRIDE POWDERSR--B--Fe* Before Corrosion Test After Corrosion Test SAM- NiO TO- ALLOY RUST Br iHc BH max Br iHc BH max PLE POWDER CrN MnN.sub.4 ZrN HfN TiN NbN Ni.sub.2 N Si.sub.3 N.sub.4 GeN VN GaN AlN Co.sub.3 N TAL POWDER STATE (KG) (KOe) (MGOe) (KG) (KOe) (MGOe) EXAMPLES 358 0.1 -- -- -- -- -- -- -- -- -- -- -- 0.5 -- 0.5 remainder absent 12.1 22.2 35.2 12.1 22.1 35.2 359 1.5 -- -- -- -- -- -- -- -- -- -- -- 0.01 -- 0.01 .uparw. .uparw. 12.1 21.7 35.0 12.1 21.7 35.0 360 2.4 -- -- -- -- -- -- -- -- -- -- -- 0.0005 -- 0.0005 .uparw. .uparw. 12.0 21.5 34.8 12.0 21.5 34.8 361 0.0006 -- -- -- -- -- -- -- -- -- -- -- -- 0.01 0.01 .uparw. .uparw. 12.1 21.5 35.0 12.1 21.3 34.8 362 0.02 -- -- -- -- -- -- -- -- -- -- -- -- 1.1 1.1 .uparw. .uparw. 12.2 21.6 35.5 12.1 21.4 34.9 363 0.8 -- -- -- -- -- -- -- -- -- -- -- -- 2.9 2.9 .uparw. .uparw. 12.2 21.9 35.9 12.2 21.8 35.2 364 1.6 -- -- -- -- -- -- -- -- -- -- -- -- 2.0 2.0 .uparw. .uparw. 12.2 21.8 35.5 12.1 21.5 35.0 365 2.4 -- -- -- -- -- -- -- -- -- -- -- -- 0.0005 0.0005 .uparw. .uparw. 12.1 21.5 35.2 12.0 21.4 34.7 366 1.2 0.6 0.5 -- -- -- -- -- -- -- -- -- -- -- 1.1 .uparw. .uparw. 12.2 21.3 35.3 12.2 21.2 35.2 367 1.2 0.5 -- 0.5 -- 0.3 -- -- -- -- -- -- -- -- 1.3 .uparw. .uparw. 12.2 21.2 35.2 12.2 21.1 35.2 368 1.2 1.1 -- 0.3 0.3 -- 0.1 -- 0.1 -- -- -- -- -- 1.9 .uparw. .uparw. 12.2 21.3 35.3 12.2 21.1 35.2 369 1.2 -- 0.5 -- -- -- -- -- -- -- 1.3 -- -- 0.01 1.81 .uparw. .uparw. 12.2 21.7 35.6 12.2 21.5 35.5 370 1.2 -- -- 0.6 -- -- 0.5 -- -- 1.1 -- -- 0.1 -- 2.3 .uparw. .uparw. 12.2 21.6 35.5 12.2 21.5 35.5 371 1.2 0.1 -- -- 0.2 -- -- -- 1.1 -- -- 0.9 -- -- 2.3 .uparw. .uparw. 12.1 21.8 35.3 12.1 21.5 35.0 372 1.2 -- -- -- 0.007 1.0 -- 0.9 -- -- 0.05 -- -- 0.06 2.017 .uparw. .uparw. 12.2 21.7 35.5 12.2 21.5 35.3 373 1.2 0.01 -- 0.3 -- -- 0.8 -- -- 0.6 -- -- 0.03 -- 1.74 .uparw. .uparw. 12.1 21.2 34.9 12.1 21.0 34.8 374 1.2 -- 0.2 -- -- 0.001 -- 1.5 0.8 -- -- 0.02 -- 0.01 2.531 .uparw. .uparw. 12.2 21.5 35.3 12.2 21.3 35.2 375 1.2 1.9 -- -- 0.001 -- -- 0.7 0.01 -- 0.1 -- 0.01 -- 2.721 .uparw. .uparw. 12.2 21.7 35.5 12.2 21.5 35.3 376 1.2 -- -- 0.09 -- -- 0.005 -- -- 0.001 -- 0.04 -- -- 1.136 .uparw. .uparw. 12.2 21.3 35.3 12.1 21.0 34.8 *Alloy formed from Nd13.5%, Dy1.5%, B8%, Feremainder (here % is atomic %) TABLE 14-5__________________________________________________________________________ 9COMPOSITION OF THE POWDER (WEIGHT %)SAM- NiO NITRIDE POWDERSPLE POWDER CrN MnN.sub.4 ZrN HfN TiN NbN Ni.sub.2 N Si.sub.3 N.sub.4 GeN VN GaN AlN Co.sub.3__________________________________________________________________________ NEXAMPLES377 1.2 -- -- -- 1.6 -- -- -- -- -- -- -- -- 1.4378 1.2 -- -- 0.7 -- -- -- -- -- -- -- -- 1.2 --379 1.2 -- 1.8 -- -- -- -- -- -- -- -- 0.9 -- --380 1.2 1.3 -- -- -- -- -- -- -- -- 0.6 -- -- --381 1.2 0.1 0.1 0.3 0.1 0.2 0.1 0.3 0.3 0.3 0.1 0.1 0.1 0.1 COMPARATIVEEXAMPLES120 0.0002 0.9 -- -- -- -- -- -- -- -- -- -- -- --121 3.1 -- 0.9 -- -- -- -- -- -- -- -- -- -- --122 1.2 0.0003 -- -- -- -- -- -- -- -- -- -- -- --123 1.2 3.3 -- -- -- -- -- -- -- -- -- -- -- --124 1.2 -- 0.0002 -- -- -- -- -- -- -- -- -- -- --125 1.2 -- 3.2 -- -- -- -- -- -- -- -- -- -- --126 1.2 -- -- 0.0003 -- -- -- -- -- -- -- -- -- --127 1.2 -- -- 3.3 -- -- -- -- -- -- -- -- -- --128 1.2 -- -- -- 0.0002 -- -- -- -- -- -- -- -- --129 1.2 -- -- -- 3.2 -- -- -- -- -- -- -- -- --130 1.2 -- -- -- -- 0.0003 -- -- -- -- -- -- -- --131 1.2 -- -- -- -- 3.3 -- -- -- -- -- -- -- --132 1.2 -- -- -- -- -- 0.0001 -- -- -- -- -- -- --133 1.2 -- -- -- -- -- 3.2 -- -- -- -- -- -- --__________________________________________________________________________ COMPOSITION OF POWDER (WEIGHT %) MAGNETICAL PROPERTIES NITRIDE R--B--Fe* Before Corrosion Test After Corrosion Test SAM- POWDERS ALLOY RUST Br iHc BH max Br iHc BH max PLE TOTAL POWDER STATE (KG) (KOe) (MGOe) (KG) (KOe) (MGOe)__________________________________________________________________________ EXAMPLES 377 3.0 remainder A 12.1 21.5 35.0 12.1 21.4 34.9 378 1.9 .uparw. .uparw. 12.2 21.8 35.5 12.2 21.6 35.4 379 2.7 .uparw. .uparw. 12.1 22.0 35.5 12.1 22.0 35.5 380 1.9 .uparw. .uparw. 12.2 21.9 35.6 12.2 21.8 35.5 381 2.2 .uparw. .uparw. 12.1 21.4 34.9 12.1 21.2 34.7 COMPARATIVE EXAMPLES 120 0.9 .uparw. P 12.1 20.3 34.8 10.5 10.2 23.5 121 0.9 .uparw. A 10.4 8.8 22.4 10.4 8.8 22.4 122 0.0003 .uparw. P 12.1 20.3 34.8 10.4 9.8 22.7 123 3.3 .uparw. A 10.3 10.5 22.0 10.3 10.5 22.0 124 0.0002 .uparw. P 12.0 20.4 34.7 10.3 9.9 21.5 125 3.2 .uparw. A 10.4 10.1 21.8 10.4 10.1 21.8 126 0.0003 .uparw. P 12.0 20.3 34.6 10.3 10.1 21.7 127 3.3 .uparw. A 10.3 9.8 21.0 10.3 9.8 21.0 128 0.0002 .uparw. P 12.0 20.4 34.7 10.4 9.8 21.5 129 3.2 .uparw. A 10.4 10.2 22.0 10.4 10.2 22.0 130 0.0003 .uparw. P 12.0 20.2 34.8 10.4 10.5 22.2 131 3.3 .uparw. A 10.5 10.3 22.9 10.5 10.3 22.9 132 0.0001 .uparw. P 12.0 20.7 34.9 10.4 10.5 22.2 133 3.2 .uparw. A 10.5 10.8 23.8 10.5 10.8 23.8__________________________________________________________________________ *Alloy formed forn Nd13.5%, Dy1.5%, B8%, Feremainder (here % is atomic %) indicates values outside of the range of the present invention A is absent, P is present indicates values outside of the range of the present invention TABLE 14-6__________________________________________________________________________COMPOSITION OF THE POWDER (WEIGHT %)NiOSAM- POW- NITRIDE POWDERSPLE DER CrN MnN.sub.4 ZrN HfN TiN NbN Ni.sub.2 N Si.sub.3 N.sub.4 GeN VN GaN AlN Co.sub.3__________________________________________________________________________ NEXAMPLES134 1.2 -- -- -- -- -- -- 0.0003 -- -- -- -- -- --135 1.2 -- -- -- -- -- -- 3.3 -- -- -- -- -- --136 1.3 -- -- -- -- -- -- -- 0.0002 -- -- -- -- --137 1.2 -- -- -- -- -- -- -- 3.3 -- -- -- -- --138 1.2 -- -- -- -- -- -- -- -- 0.0003 -- -- -- --139 1.2 -- -- -- -- -- -- -- -- 3.3 -- -- -- --140 1.2 -- -- -- -- -- -- -- -- -- 0.0002 -- -- --141 1.2 -- -- -- -- -- -- -- -- -- 3.2 -- -- --142 1.2 -- -- -- -- -- -- -- -- -- -- 0.0003 -- --143 1.2 -- -- -- -- -- -- -- -- -- -- 3.3 -- --144 1.2 -- -- -- -- -- -- -- -- -- -- -- 0.0001 --145 1.2 -- -- -- -- -- -- -- -- -- -- -- 3.2 --146 1.2 -- -- -- -- -- -- -- -- -- -- -- -- 0.0002147 1.2 -- -- -- -- -- -- -- -- -- -- -- -- 3.3148 1.2 0.5 0.5 -- -- 0.5 -- 0.5 0.5 -- 0.5 -- 0.5 --149 -- 0.5 -- 0.5 -- 0.5 -- -- -- -- -- -- -- --150 -- -- -- -- -- -- -- -- -- -- -- -- -- --__________________________________________________________________________ COMPOSITION OF THE POWDER (WEIGHT %) MAGNETICAL PROPERTIES NITRIDE R-B--Fe* Before Corrosion Test After Corrosion Test SAM- POWDERS ALLOY RUST Br iHc BH max Br iHc BH max PLE TOTAL POWDER STATE (KG) (KOc) (MGOe) (KG) (KOc) (MGOe)__________________________________________________________________________ EXAMPLES 134 0.0003 remainder present 12.0 20.4 34.8 10.5 10.4 23.1 135 3.3 .uparw. absent 10.4 9.5 21.0 10.4 9.5 21.0 136 0.0002 .uparw. present 12.0 20.3 34.6 10.5 9.8 22.3 137 3.3 .uparw. absent 10.3 10.1 22.0 10.3 10.1 22.0 138 0.0003 .uparw. present 12.0 20.4 34.7 10.5 9.0 21.5 139 3.3 .uparw. absent 10.3 10.5 21.9 10.3 10.5 21.9 140 0.0002 .uparw. present 12.0 20.5 34.8 10.4 10.1 21.8 141 3.2 .uparw. absent 10.4 10.9 23.0 10.4 10.9 23.0 412 0.0003 .uparw. present 12.0 20.6 34.8 10.4 9.8 21.5 143 3.3 .uparw. absent 10.3 10.7 22.1 10.3 10.7 22.1 144 0.0001 .uparw. present 12.0 20.6 34.8 10.3 9.8 21.3 145 3.2 .uparw. absent 10.4 10.5 22.2 10.4 10.5 22.2 146 0.0002 .uparw. present 12.0 20.3 34.7 10.2 9.0 19.8 147 3.3 .uparw. absent 10.3 9.5 20.8 10.3 9.5 20.8 148 3.5 .uparw. absent 10.4 10.3 22.1 10.4 10.3 22.1 149 1.5 .uparw. present 12.0 20.9 35.0 10.4 10.5 22.2 150 -- .uparw. heavy 12.0 20.2 34.5 10.5 8.1 22.1__________________________________________________________________________ *Alloy formed from Nd13.5%, Dy1.5%, B8%, Feremainder (here % is atomic %) indicates values outside of the range of the present invention TABLE 15 COMPOSITION OF THE POWDER (WEIGHT %) R--B--Fe* OXIDE POWDERS NITRIDE POWDERS ALLOY SAMPLE Cr.sub.2 O.sub.3 NiO CrN MnN.sub.4 ZrN HfN TiN NbN N i.sub.2 N Si.sub.3 N.sub.4 GeN V N GaN AlN Co.sub.3 N TOTAL POWDER EXAMPLES 382 0.0003 0.0003 0.0006 0.0001 -- 0.0001 0.0001 0.0001 -- -- -- -- 0.0001 0.0001 0.0001 -- 0.0007 remainder 383 0.0008 0.0002 0.001 2.0 -- -- -- -- 0.1 -- 0.1 0.1 -- 0.4 0.1 0.1 2.9 .uparw. 384 0.008 0.002 0.001 0.6 -- -- -- 0.9 -- -- -- -- -- 1.0 -- -- 2.5 .uparw. 385 0.01 0.03 0.04 -- -- -- 0.7 -- 1.0 -- -- -- -- -- -- -- 1.7 .uparw. 386 0.05 0.05 0.1 -- 0.1 -- -- -- -- -- 0.1 0.1 -- -- -- -- 0.3 .uparw. 387 0.4 0.6 1.0 1.0 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 2.2 .uparw. 388 0.5 1.0 1.5 0.1 -- -- 0.3 -- 0.3 -- -- -- -- -- -- -- 0.7 .uparw. 389 0.3 0.1 0.4 0.3 -- 0.7 -- -- -- -- -- -- -- -- -- -- 1.0 .uparw. 390 0.5 0.4 0.9 -- -- 1.0 -- 1.0 -- -- -- -- 0.2 -- -- -- 2.2 .uparw. 391 0.5 1.4 1.9 1.0 -- -- 0.8 -- -- -- 0.05 -- 0.05 -- -- -- 1.9 .uparw. 392 2.0 0.3 2.3 -- -- -- -- -- -- -- -- -- -- 1.2 0.4 -- 1.6 .uparw. 393 2.0 1.5 2.5 1.7 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 2.9 .uparw. 394 0.3 0.4 0.7 0.03 -- -- -- 0.03 -- -- -- -- -- -- 0.02 -- 0.08 .uparw. COMPARATIVE EXAMPLES 151 0.3 0.1 0.4 0.0001 0.0001 -- -- -- -- -- -- -- -- -- -- -- 0.0002 .uparw. 152 2.0 1.1 31. 1.0 -- -- 1.0 -- -- -- -- -- -- -- -- 1.0 3.0 .uparw. 153 0.08 0.02 0.1 2.0 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 3.2 .uparw. 154 0.0002 0.0002 0.0004 2.0 -- -- -- -- -- 0.3 -- -- -- -- 0.2 -- 2.5 .uparw. 155 0.0001 0.0001 0.0002 0.0001 -- -- -- 0.0001 -- -- -- -- -- -- -- -- 0.0002 .uparw. 154 1.4 1.9 3.3 2.0 -- 0.3 -- 0.3 -- 0.3 -- 0.3 -- -- 0.3 -- 3.5 *Alloy formed from Nd13.5%, Dy1.5%, B8%, Feremainder (here % is atomic %) indicates values outside of the range of the present invention TABLE 16__________________________________________________________________________ . MAGNETICAL PROPERTIES PRIOR TO ANTI-CORROSION TEST AFTER ANTI-CORROSION TEST Br iHc BH max Br iHc BH maxSAMPLE RUST STATE (KG) (KOe) (MGOe) (KG) (KOe) (MGOe)__________________________________________________________________________EXAMPLES382 absent 12.2 21.5 35.5 12.2 21.3 35.3383 .uparw. 12.1 19.6 34.9 12.1 19.6 34.9384 .uparw. 12.2 22.0 35.8 12.2 21.8 35.6385 .uparw. 12.2 21.3 35.3 12.2 21.2 35.2386 .uparw. 12.2 21.3 35.3 12.2 21.2 35.2387 .uparw. 12.2 21.3 35.3 12.1 19.8 34.5388 .uparw. 12.2 21.4 35.4 12.2 21.4 35.4389 .uparw. 12.2 21.6 35.6 12.1 21.3 35.0390 .uparw. 12.2 21.1 35.2 12.2 20.8 35.2391 .uparw. 12.2 21.3 35.3 12.1 19.8 34.5392 .uparw. 12.3 20.8 36.3 12.3 20.5 36.0393 .uparw. 12.3 20.8 36.3 12.3 20.8 36.3394 .uparw. 12.2 21.6 35.5 12.1 21.3 35.3COMPARATIVEEXAMPLES151 .uparw. 12.1 20.1 35.0 11.1 12.2 22.0152 .uparw. 10.1 12.0 20.1 10.1 11.8 20.0153 .uparw. 10.5 12.1 23.2 10.5 12.0 23.1154 present 12.3 21.1 36.5 10.6 12.3 22.1155 absent 12.1 22.2 35.2 12.1 21.5 35.0156 .uparw. 10.8 8.9 20.2 10.8 8.9 20.0__________________________________________________________________________ TABLE 17__________________________________________________________________________Boundary Phase MAGNETICAL PROPERTIESComposition (weight %) AFTER ANTI-CORROSION TESTSAM- Matellic Nd-Rich RUST PRIOR TO ANTI-CORROSION TEST BH maxPLE Element Oxide Phase STATE Br (KG) iHc (KOe) BH max (MGOe) Br (KG) iHc (KOe) (MGOe)__________________________________________________________________________EXAMPLES395 Ni: 25 60 remainder absent 12.6 13.5 37.9 12.4 13.3 37.0396 Co: 22 58 .uparw. .uparw. 12.6 13.7 38.0 12.4 13.5 37.1397 Mn: 40 43 .uparw. .uparw. 12.5 14.0 38.1 12.5 13.8 38.0398 Cr: 50 38 .uparw. .uparw. 12.3 14.7 37.0 12.3 14.6 37.0399 Ti: 22 68 .uparw. .uparw. 12.4 14.6 37.8 12.4 14.4 37.7400 V: 43 31 .uparw. .uparw. 12.4 14.2 37.7 12.4 14.1 37.6401 Al: 31 46 .uparw. .uparw. 12.3 14.5 36.9 12.3 14.3 36.8402 Ga: 36 40 .uparw. .uparw. 12.5 13.8 38.0 12.5 13.6 37.9403 In: 21 36 .uparw. .uparw. 12.5 13.5 37.8 12.5 13.2 37.6404 Zr: 25 48 .uparw. .uparw. 12.6 13.4 37.9 12.5 13.0 37.2405 Hf: 55 40 .uparw. .uparw. 12.5 14.1 38.1 12.5 14.0 38.1406 Nb: 47 34 .uparw. .uparw. 12.5 14.2 38.2 12.5 14.0 38.1407 Dy: 55 31 .uparw. .uparw. 12.3 15.0 37.0 12.3 14.8 37.0408 Y: 52 45 .uparw. .uparw. 12.5 13.9 38.0 12.5 13.8 38.0409 Ni: 5 32 .uparw. .uparw. 12.3 14.8 36.9 12.3 14.7 36.9 Dy: 38410 Mn: 5 60 .uparw. .uparw. 12.5 14.0 38.1 12.5 13.9 38.0 Cr: 25411 Cr: 5 Y: 36 51 .uparw. .uparw. 12.5 14.1 38.1 12.5 14.0 38.1157 -- -- 100 heavy 12.5 12.5 36.8 11.2 7.5 22.0__________________________________________________________________________ TABLE 18__________________________________________________________________________Boundary PhaseComposition (weight %) MAGNETICAL PROPERTIESMetallic Nd-Rich RUST PRIOR TO ANTI-CORROSION TEST AFTER ANTI-CORROSION TESTSAMPLE Element Phase STATE Br (KG) iHc (KOe) BH max (MGOe) Br (KG) iHc (KOe) BH max__________________________________________________________________________ (MGOe)EXAMPLES412 Zr: 25 remainder absent 12.6 13.6 38.0 12.4 13.2 37.0413 Ta: 45 .uparw. .uparw. 12.5 13.5 37.8 12.3 13.2 36.2414 Ti: 85 .uparw. .uparw. 12.5 14.5 38.3 12.4 14.1 37.6415 Nb: 59 .uparw. .uparw. 12.5 14.3 38.2 12.4 13.9 37.5416 V: 88 .uparw. .uparw. 12.4 14.5 37.8 12.4 14.1 37.6417 Hf: 52 .uparw. .uparw. 12.5 13.9 38.0 12.4 13.6 37.4418 Y: 63 .uparw. .uparw. 12.6 13.8 38.2 12.5 13.6 37.8419 Ni: 5 Ti: 41 .uparw. .uparw. 12.6 13.8 38.2 12.5 13.5 37.7420 V: 33 Y: 36 .uparw. .uparw. 12.5 14.0 38.1 12.4 13.8 37.5421 Nb: 21 .uparw. .uparw. 12.5 13.6 37.8 12.3 13.3 36.3 Hf: 23422 Zr: 12 .uparw. .uparw. 12.5 13.9 38.0 12.4 13.7 37.4 Y: 62__________________________________________________________________________

Potential for Industrial Applications

The sintered rare earth metal-boron-iron alloy magnets of the present invention may be used for any industrial device which requires magnets with superior magnetic and anti-corrosion properties.

Claims

1. A manufacturing method for sintered rare earth metal-B-Fe alloy magnets comprising the steps of

a) preparing a powder obtained by adding at least one additive agent of an oxide powder of Al, Ga, Ni, Co, Mn, Cr, Ti, V, Nb, Y, Ho, Er, Tm, Lu, Zr or Eu, or a hydride powder of Zr, Ta, Ti, Nb, V, Hf, or Y, to R-B-Fe alloy powder wherein R is a rare earth element or Y, the amount of said additive agent totaling from 0.0005 to 3.0 weight %,

b) molding the alloy powder and additive agent; and,

c) sintering the molded alloy powder and additive agent.

2. A manufacturing method for sintered rare earth metal-B-Fe alloy magnets in accordance with claim 1 wherein the additive agent is Al an Zr oxide powders.

3. A manufacturing method for sintered rare earth metal-B-Fe alloy magnets in accordance with claim 1 wherein the additive agent is Al and Cr oxide powders.

4. A manufacturing method for sintered rare earth metal-B-Fe alloy magnets in accordance with claim 1 wherein the additive agent is Al and Ti oxide powders.

5. A manufacturing method for sintered rare earth metal-B-Fe alloy magnets in accordance with claim 1 wherein the additive agent is Al, Zr, and Cr oxide powders.

6. A manufacturing method for sintered rare earth metal-B-Fe alloy magnets in accordance with claim 1 wherein the additive agent is Al, Zr, and Ti oxide powders.

7. A manufacturing method for sintered rare earth metal-B-Fe alloy magnets in accordance with claim 1 wherein the additive agent is Al, Cr, and Ti oxide powders.

8. A manufacturing method for sintered rare earth metal-B-Fe alloy magnets in accordance with claim 1 wherein the additive agent is Al, Zr, Cr, and Ti oxide powders.

9. A manufacturing method for sintered rare earth metal-B-Fe alloy magnets in accordance with claim 1 wherein the additive agent is Ga and Al oxide powders.

10. A manufacturing method for sintered rare earth metal-B-Fe alloy magnets in accordance with claim 1 wherein the additive agent is Ga and Cr oxide powders.

11. A manufacturing method for sintered rare earth metal-B-Fe alloy magnets in accordance with claim 1 wherein the additive agent is Ga and V oxide powders.

12. A manufacturing method for sintered rare earth metal-B-Fe alloy magnets in accordance with claim 1 wherein the additive agent is Ga, Al, and Cr oxide powders.

13. A manufacturing method for sintered rare earth metal-B-Fe alloy magnets in accordance with claim 1 wherein the additive agent is Ga, Cr, and V oxide powders.

14. A manufacturing method for sintered rare earth metal-B-Fe alloy magnets in accordance with claim 1 wherein the additive agent is Ga, Al, and V oxide powders.

15. A manufacturing method for sintered rare earth metal-B-Fe alloy magnets in accordance with claim 1 wherein the additive agent is Ga, Al, Cr, and V oxide powders.

16. A manufacturing method for sintered rare earth metal-B-Fe alloy magnets in accordance with claim 1 wherein the additive agent is a hydride powder and R is a rare earth element.

17. A manufacturing method for sintered rare earth metal-B-Fe alloy magnets in accordance with claim 1 wherein the additive agent is an oxide powder of Y, Ho, Er, Tm, Lu, or Eu and R is a rare earth element of Nd, Pr, La, Ce, Dy, Sm, Tb, Gd, or Yb.

18. A manufacturing method for sintered rare earth metal-B-Fe alloy magnets in accordance with claim 1 wherein the additive agent is a Cr oxide powder and additionally comprising at least one nitride powder of Cr, Mn, Zr, Hf, Ti, Nb, Si, Ge, V, Ga, Al, or Co in an amount totaling from 0.0005 to 3.0 weight %.

19. A manufacturing method for sintered rare earth metal-B-Fe alloy magnets in accordance with claim 1 wherein the additive is a Ni oxide powder and additionally comprising at least one nitride powder of Cr, Mn, Zr, Hf, Ti, Nb, Si, Ge, V, Ga, Al, or Co in an amount totaling from 0.0005 to 3.0 weight %.

20. A manufacturing method for sintered rare earth metal-B-Fe alloy magnets in accordance with claim 1 wherein the additive agent is Cr and Ni oxide powders, and at least one nitride powder of Cr, Mn, Zr, Hf, Ti, Nb, Si, Ge, V, Ga, Al, or Co in an amount totaling from 0.0005 to 3.0 weight %.

21. A manufacturing method for sintered rare earth metal-B-Fe alloy magnets in accordance with any one of claims 1 through 20 including heat treating the sintered compact.

22. A sintered rare earth metal-B-Fe alloy magnet comprising a R.sub.2 Fe.sub.14 B phase and an inter-granular boundary phase around said R.sub.2 Fe.sub.14 B phase, wherein R is a rare earth element or Y and said inter-granular boundary phase comprises at least one of Ni, Co, Mn, Cr, Ti, V, Al, Ga, In, Zr, Hf, Ta, Nb, Mo, Si, Re, or W in an amount of 20 to 90 atomic %.

23. A sintered rare earth metal-B-Fe alloy magnet in accordance with claim 22 additionally comprising oxygen in an amount of 30 to 70 atomic % in said inter-granular boundary phase.

24. A sintered rare earth metal-B-Fe alloy magnet comprising a R.sub.2 Fe.sub.14 B phase and an inter-granular boundary phase around said R.sub.2 Fe.sub.14 B phase, wherein R is a rare earth element or Y and said inter-granular boundary phase comprises R in an amount of 20 to 90 atomic % and oxygen in an amount of 30 to 70 atomic %.

25. A sintered rare earth metal-B-Fe alloy magnet in accordance with claim 24 additionally comprising at least one of Ni, Co, Mn, Cr, T, V, Al, Ga, In, Zr, Hf, Ta, Nb, Mo, Sn, Re, or W in an amount of 20 to 90 atomic % in said inter-granular boundary phase.