Patent Application
20130314198
The present invention relates to a core having excellent magnetic properties for use in distribution transformers, reactors, choke coils, magnetic switches, etc., a quenched, Fe-based soft-magnetic alloy ribbon constituting such core, and its production method.
As soft-magnetic materials used for cores for distribution transformers, etc., silicon steel, and ribbons of Fe-based amorphous alloys and Fe-based nanocrystalline alloys are known. Silicon steel is inexpensive and has a high magnetic flux density, but it suffers larger core loss than the Fe-based amorphous alloys. Though the Fe-based amorphous alloy ribbons produced by a rapid quenching method such as a single roll method have lower saturation magnetic flux densities than that of the silicon steel, they have lower core loss because they do not have magnetocrystalline anisotropy for the absence of crystals. Accordingly, they are used for cores for distribution transformers, etc. (for example, see JP 2006-45662 A).
Fe-based nanocrystalline alloy ribbons having nano-sized fine crystal grains, which are formed at high number densities in the alloys by heat-treating the Fe-based amorphous alloys produced by a rapid quenching method such as a single roll method, which may partially have crystal phases, have high saturation magnetic flux densities, as well as higher permeability, lower core loss and lower magnetostriction than those of the Fe-based amorphous alloy ribbons. Accordingly, they are mainly used for cores for choke coils, current sensors, etc.
in electronic parts. Known as typical Fe-based nanocrystalline alloys are Fe-Cu-Nb-Si-B alloys, Fe-Zr-B alloys, etc. Fe-based nanocrystalline alloy ribbons having as high saturation magnetic flux density as about 1.8 T, which are suitable for distribution transformer cores, have recently been proposed (see JP 2007-107095 A).
The Fe-based amorphous alloy ribbons are usually produced by a rapid quenching method such as a single roll method, etc. The single roll method is a method for producing an alloy ribbon by ejecting an alloy melt from a nozzle onto a cooling roll made of a high-conductivity alloy, which is rotating at a high speed. The cooling roll is made of Cu alloys with good thermal conduction, such as Cu-Cr alloys, Cu-Ti alloys, Cu-Cr-Zr alloys, Cu-Ni-Si alloys, Cu-Be alloys, etc. To improve productivity, long, wide amorphous alloy ribbons are produced.
The Fe-based amorphous alloys such as Fe-Si-B alloys, etc. used for distribution transformers, etc. have small hysteresis loss because of small magnetic hysteresis. It is known, however, that the eddy current loss (core loss−hysteresis loss) of the Fe-based amorphous alloy in a broad sense is several tens to 100 times as large as the classical eddy current loss determined under the assumption of uniform magnetization. This increased loss is called anomalous eddy current loss or excess loss, which is generated mainly by uneven magnetization change due to large magnetic domain widths of the alloy. To reduce the anomalous eddy current loss, various methods of dividing magnetic domains finer have been attempted.
Known as methods of reducing the anomalous eddy current loss of the Fe-based amorphous alloy ribbon are a method of mechanically scratching a surface of the Fe-based amorphous alloy ribbon (JP 62-49964 B), a laser scribing method of irradiating a surface of the Fe-based amorphous alloy ribbon with laser beams for local melting and solidification by quenching to divide magnetic domains finer, etc. As the laser scribing method, for example, JP 3-32886 B discloses a method of irradiating an amorphous alloy ribbon with pulse laser beams in a transverse direction, thereby melting a surface of the amorphous alloy ribbon locally and instantaneously, and then solidifying it by quenching to form amorphized spots in lines, which divide magnetic domains finer. However, the laser scribing method has low productivity because of a small amount of treatments per a unit area.
JP 61-24208 A discloses a method of controlling the pitches and heights of wave-like undulations in desired ranges at the time of producing an amorphous alloy ribbon having wave-like undulations on a free surface by a single roll method, to divide magnetic domains finer, thereby reducing eddy current loss. This method has higher productivity than the laser scribing method, because the wave-like undulations are formed at the time of production of the amorphous alloy ribbon.
The formation of wave-like undulations on a free surface of an amorphous alloy ribbon produced by a single roll method appears to be due to the vibration of a melt paddle on a cooling roll. However, transverse troughs constituting the wave-like undulations are usually not straight but meandering like waves. Troughs reduce eddy current loss by the division of magnetic domains, but the meandering of transverse troughs increases hysteresis loss. Increased hysteresis loss is serious particularly in wide amorphous alloy ribbons. It is thus desired to provide amorphous alloy ribbons, in which the meandering of transverse troughs constituting the wave-like undulations is as small as possible.
With respect to the suppression of the vibration of a melt paddle, JP 2002-316243 A discloses a method for producing an amorphous alloy ribbon by quenching an alloy melt on a cooling roll, a CO2 gas being blown onto the alloy melt, while the cooling roll is ground. To grind the cooling roll, a brush of brass or stainless steel wires of 0.06 mm in diameter, etc. are used. JP 2002-316243 A describes that if a brush used for grinding were too hard, a ground surface of the cooling roll would have too deep scratches, resulting in cutting of the amorphous alloy ribbons, and little effect of improving surface roughness, and that therefor the brush hardness is preferably equal to or less than the hardness of the cooling roll. However, amorphous alloy ribbons obtained by the method described in JP 2002-316243 A have large core loss despite wave-like undulations on free surfaces.
Accordingly, an object of the present invention is to provide a quenched, Fe-based soft-magnetic alloy ribbon with reduced core loss, a core formed thereby, and a method for producing such quenched, Fe-based soft-magnetic alloy ribbon.
As a result of intensive research in view of the above object, it has been found that (a) a large core loss of the amorphous alloy ribbon obtained by the method described in JP 2002-316243 A is due to large hysteresis loss; that (b) the hysteresis loss depends on the meandering level of transverse troughs constituting the wave-like undulations; that (c) the vibration of the melt paddle should be reduced to suppress the transverse troughs; that (d) the suppression of the vibration of a melt paddle is not sufficiently achieved by merely grinding a surface of a cooling roll by a brush; and that (e) a combination of fine linear scratches formed on a surface of a cooling roll ground by a brush and a desired temperature distribution range in a nozzle ejecting an alloy melt can suppress the vibration of a melt paddle, thereby suppressing the meandering of the transverse troughs. It has also been found that the depths of linear scratches formed on a ground surface of a cooling roll are determined not only by the hardness of a brush, but also by the pressure of a brush onto a cooling roll, the number and direction of rotation of a brush, the number of wires in a brush coming into contact with a unit area of a cooling roll, etc. Particularly in the production of amorphous alloy ribbons for a long period of time, a cooling roll surface is roughened by oxides attached, etc., needing the grinding of a cooling roll surface. In such case, it has been found that forming fine linear scratches with desired roughness instead of grinding a roll to have a mirror surface is necessary to suppress the vibration of the melt paddle effectively.
As a result, the inventors have found that when an alloy melt is ejected onto a rotating cooling roll, (a) while keeping a transverse temperature distribution in a melt nozzle within ±15° C. to provide a melt paddle with as small a temperature distribution as possible, and (b) while grinding a cooling roll surface by a wire brush to form fine linear scratches having an average roughness Ra of 0.1-1 μm and a maximum roughness depth Rmax of 0.5-10 μm, a quenched, Fe-based soft-magnetic alloy ribbon having wave-like undulations on a free surface is formed, transverse troughs in the wave-like undulations having reduced meandering. The present invention has been completed based on such findings.
Thus, the quenched, Fe-based soft-magnetic alloy ribbon of the present invention has wave-like undulations on a free surface, the wave-like undulations having transverse troughs arranged at substantially constant intervals in a longitudinal direction, and the troughs having an average amplitude D of 20 mm or less.
Ridges extending in a transverse direction are preferably formed in regions longitudinally adjacent to the troughs.
Regions having the troughs preferably occupy 70% or more of the width of the ribbon with the longitudinal centerline of the ribbon as a center. It is more preferable that the troughs continuously extend fully between both side ends of the ribbon.
The troughs preferably have longitudinal intervals L in a range of 1-5 mm. The ribbon preferably has a thickness T in a range of 15-35 μm. A ratio t/T of an average height difference t between the troughs and the ridges to the thickness of the ribbon is preferably in a range of 0.02-0.2.
The quenched, Fe-based soft-magnetic alloy ribbon is preferably formed by an Fe-based amorphous alloy or an Fe-based fine-crystalline alloy partially having crystal phases.
The method of the present invention for producing a quenched, Fe-based soft-magnetic alloy ribbon having wave-like undulations on a free surface, the wave-like undulations having transverse troughs arranged at substantially constant intervals in a longitudinal direction, and the troughs having an average amplitude D of 20 mm or less, comprises the steps of (a) keeping a transverse temperature distribution in a melt nozzle within ±15° C. to have as small a temperature distribution as possible in a melt paddle of the alloy; and (b) forming numerous fine linear scratches on a cooling roll surface by a wire brush, thereby providing a ground surface of the cooling roll with an average roughness Ra of 0.1-1 μm and a maximum roughness depth Rmax of 0.5-10 μm.
In the above method, it is preferable to use a heating nozzle having a slit-shaped opening for blowing a heating gas onto the melt nozzle, the length of the slit-shaped opening of the heating nozzle being 1.2-2 times the horizontal length of a slit-shaped orifice of the melt nozzle.
The core of the present invention is formed by laminating or winding the above quenched, Fe-based soft-magnetic alloy ribbon.
The core of the present invention is preferably heat-treated in a magnetic field in a magnetic path direction.
a) is a schematic view showing one example of apparatuses for producing the quenched, Fe-based soft-magnetic alloy ribbon of the present invention.
b) is a schematic view showing another example of apparatuses for producing the quenched, Fe-based soft-magnetic alloy ribbon of the present invention
a) is a partial cross-sectional view showing in detail a melt nozzle and its vicinity in the apparatus of
b) is a cross-sectional view taken along the line A-A in
[1] Principle
When an Fe-based soft-magnetic alloy ribbon made of an Fe-based amorphous alloy or an Fe-based fine-crystalline alloy partially having crystal phases is produced by a single roll method, a melt paddle formed between a melt nozzle and a cooling roll is inevitably vibrated. The vibration of the melt paddle is affected by the viscosity and surface tension of the melt paddle, the temperature distribution of a melt nozzle, the surface conditions of a cooling roll, etc. The temperature distribution of the melt nozzle would cause the local deformation of the melt nozzle, the thickness-direction variations of a gap between the melt nozzle and the cooling roll, etc. The temperature distribution of the melt paddle would cause oxides, etc. to attach to a portion of the cooling roll surface in contact with a low-temperature portion of the melt paddle, resulting in larger melt paddle vibration. The vibration of the melt paddle increases as a wider Fe-based soft-magnetic alloy ribbon is produced, specifically remarkable in the case of an Fe-based soft-magnetic alloy ribbon as wide as 20 mm or more, particularly 50 mm or more. This appears to be due to the fact that a wider Fe-based soft-magnetic alloy ribbon is more affected by the temperature distribution of the melt paddle.
Larger vibration of the melt paddle provides a free surface of the Fe-based soft-magnetic alloy ribbon with larger wave-like undulations, resulting in larger transverse-direction disturbance of individual troughs constituting the wave-like undulations. The transverse-direction disturbance of troughs hinders the movement of magnetic domain walls, resulting in increased hysteresis loss.
As a result of intensive research to solve this problem, it has been found that though heating a melt nozzle at a constant temperature is effective to prevent the vibration of the melt paddle, it is likely to cause the attachment of oxides, etc., which causes the vibration of the melt paddle. Further investigation has revealed that the vibration of the melt paddle can be effectively reduced by making the temperature variations of the melt nozzle as small as possible in a transverse direction, and by grinding the cooling roll surface with a wire brush to form numerous fine linear scratches. This is completely contradictory to a conventional idea that a cooling roll had better have as mirror-finished a surface as possible. Thus, the present invention is based on the discovery that the formation of fine linear scratches on the cooling roll surface reduces the temperature distribution of the melt nozzle, thereby increasing an effect of suppressing the vibration of the melt paddle.
[2] Quenched, Fe-based soft-magnetic alloy ribbon
As shown in
When the average amplitude D representing the transverse-direction disturbance of the troughs 3 is 20 mm or less, eddy current loss is reduced with hysteresis loss suppressed. The average amplitude D of more than 20 mm provides increased hysteresis loss. This appears to be due to the fact that magnetic energy changes near the troughs 3, but increase in the transverse-direction disturbance of troughs 3 results in larger transverse-direction variations of magnetic energy, so that magnetic domain walls are likely trapped at positions having low magnetic energy, hindering smooth movement of magnetic domain walls. Further, the transverse-direction disturbance of troughs 3 tends to increase the percentage of magnetic domains having magnetization directions not in parallel with the longitudinal direction of the ribbon 1, thereby increasing exciting power. Thus, because the average amplitude D of more than 20 mm increases hysteresis loss and exciting power, the average amplitude D of the troughs 3 should be 20 mm or less. The average amplitude D of the troughs 3 is preferably 5 mm or less, more preferably 0.1-2 mm.
As shown in
There are ridges 4 in regions longitudinally adjacent to the troughs 3. To obtain a sufficient effect of reducing eddy current loss, an average height difference t between troughs 3 and ridges 4 is preferably 0.3-7 μm, more preferably 1-4 μm. The average height difference t is determined by selecting five arbitrary regions of 50 mm long in a longitudinal direction, calculating an average height difference between troughs 3 and ridges 4 in each region, and averaging them in five regions. The thickness T of the ribbon 1 is preferably in a range of 15-35 μm. A ratio t/T of the average height difference t between troughs 3 and ridges 4 to the thickness T of the ribbon 1 is preferably in a range of 0.02-0.2. The ratio t/T of less than 0.02 provides a small effect of reducing eddy current loss, and the ratio t/T of more than 0.2 increases the apparent power, and reduces the space factor of a core. The more preferred range of t/T is 0.04-0.15.
The Fe-based amorphous alloys include Fe-B alloys, Fe-Si-B alloys, Fe-Si-B-C alloys, Fe-Si-B-P alloys, Fe-Si-B-C-P alloys, Fe-P-B alloys, Fe-P-C alloys, etc., and among them, the Fe-Si-B alloys are suitable from the aspect of thermal stability and easiness of production. The Fe-based amorphous, soft-magnetic alloy ribbon may contain Co, Ni, Mn, Cr, V, Mo, Nb, Ta, Hf, Zr, Ti, Cu, Au, Ag, Sn, Ge, Re, Ru, Zn, In, Ga, etc., if necessary.
One example of the Fe-based amorphous alloys has a composition represented by Fe100-a-b-cMaSibBc (atomic %), wherein M is at least one element selected from the group consisting of Cr, Mn, Ti, V, Zr, Nb, Mo, Hf, Ta, W and Sn, 0≦a≦10, 0≦b≦20, 4≦c≦20, and 10≦a+b+c≦35. M has an effect of accelerating amorphization. To control the induced magnetic anisotropy, less than 50 atomic % of Fe may be substituted by Co and/or Ni. Co has an effect of improving the saturation magnetic flux density. Also, 50% by mass or less of M may be substituted by at least one element selected from the group consisting of Zn, As, Se, Sb, In, Cd, Ag, Bi, Mg, Sc, Re, Au, platinum-group elements, Y and rare earth elements. Further, to improve corrosion resistance and thermal stability, 50 atomic % or less of the total amount of Si and B may be substituted by at least one element selected from the group consisting of C, Al, P, Ga and Ge.
The Fe-based fine-crystalline alloys partially having crystal phases include Fe-Cu-Si-B alloys, Fe-Cu-Si-B-C alloys, Fe-Cu-Si-B-P alloys, Fe-Cu-Si-B-C-P alloys, Fe-Cu-P-B alloys, Fe-Cu-P-C alloys, etc. The
Fe-based fine-crystalline alloys may contain Co, Ni, Mn, Cr, V, Mo, Nb, Ta, Hf, Zr, Ti, Au, Ag, Sn, Ge, Re, Ru, Zn, In, Ga, etc., if necessary.
One example of the Fe-based fine-crystalline alloys has a composition represented by Fe100-a-b-c-dMaSibBcCud (atomic %), wherein M is at least one element selected from the group consisting of Ti, V, Zr, Nb, Mo, Hf, Ta and W, 0≦a≦10, 0≦b≦20, 4≦c≦20, 0.1≦d≦3, and 10≦a+b+c+d≦35. M has an effect of performing amorphization and making finer crystal grains generated by a heat treatment. To control the induced magnetic anisotropy, less than 50 atomic % of Fe may be substituted by Co and/or Ni. Co has an effect of improving the saturation magnetic flux density. Also, 50 atomic % or less of M may be substituted by at least one element selected from the group consisting of Cr, Mn, Zn, As, Se, Sb, Sn, In, Cd, Ag, Bi, Mg, Sc, Re, Au, platinum-group elements, Y and rare earth elements. Further, to adjust the magnetostriction and magnetic properties of nanocrystalline alloys, 50 atomic % or less of the total amount of Si and B may be substituted by at least one element selected from the group consisting of C, Al, P, Ga and Ge.
[3] Production method
a) shows one example of apparatuses for producing the quenched, Fe-based soft-magnetic alloy ribbon of the present invention. This apparatus comprises a crucible 12 for containing an Fe-based alloy melt 11, a high-frequency coil 13 arranged around the crucible 12 for heating the melt 11, a melt nozzle 14 disposed at the bottom of the crucible 12 for ejecting the melt 11 onto a cooling roll 15, a peeling nozzle 17 for ejecting a gas for peeling an Fe-based amorphous alloy ribbon formed by quenching on the cooling roll 15, a reel 18 for winding the Fe-based amorphous alloy ribbon 16, a heating nozzle 21 for ejecting a heating gas for keeping the temperature of the melt nozzle 14 constant, and a wire brush roll 22 disposed in contact with the cooling roll 15 upstream of the melt paddle 11a in a rotation direction. The melt nozzle 14 has a slit-shaped orifice for ejecting the melt 11.
As shown in
The wire brush roll 22 grinding a surface of the cooling roll 15 preferably comprises harder metal wires than the cooling roll 15 to form numerous fine linear scratches on the ground surface of the cooling roll 15. Such metal wires are preferably stainless steel wires. The diameters of stainless steel wires are preferably about 0.02-0.1 mm.
The roughness of fine linear scratches formed on the surface of the cooling roll 15 by grinding with the wire brush roll 22 is expressed by arithmetical mean (average) roughness (average roughness) Ra and maximum roughness depth Rmax. The arithmetical mean (average) roughness (average roughness) Ra and maximum roughness depth Rmax depend not only on the hardness and diameters of metal wires, but also on the pushing force (pressure) of the wire brush roll 22 to the cooling roll 15, the number and direction of rotation of the wire brush roll 22, the number of metal wires coming into contact with a unit area of the cooling roll 15, etc. With these conditions adjusted, the ground surface of the cooling roll 15 has an average roughness Ra of 0.1-1 μm and a maximum roughness depth Rmax of 0.5-10 μm. The average roughness Ra of less than 0.1 μm does not provide a sufficient effect of suppressing the vibration of the melt paddle 11a, and Ra of more than 1 μm provides the surface of the cooling roll 15 with too large linear scratches, resulting in a rapidly quenched, Fe-based soft-magnetic alloy ribbon with reduced magnetic properties. Likewise, the maximum roughness depth Rmax of less than 0.5 μm does not provide a sufficient effect of suppressing the vibration of the melt paddle 11a, and Rmax of more than 10 μm provides too large linear scratches on the surface of the cooling roll 15, resulting in a rapidly quenched, Fe-based soft-magnetic alloy ribbon with reduced magnetic properties. The preferred average roughness Ra is 0.2-0.8 μm, and the preferred maximum roughness depth Rmax is 1-5 μm.
The number of wire brush rolls 22 for forming fine linear scratches having the above average roughness Ra and maximum roughness depth Rmax is not restricted to one, but two or more wire brush rolls may be arranged in a rotation direction. As shown in
It is not necessarily clear why the cooling roll 15 having a ground surface having the above fine linear scratches more suppresses the vibration of the melt paddle 11a than that having a mirror surface. It is considered that a mirror-finished surface of the cooling roll 15 is not necessarily free from defects such as scratches, etc. at all, and that even the slightest defects in part of the mirror surface have large influence, unstabilizing the melt paddle 11a to cause vibration. On the other hand, the formation of fine linear scratches on the entire ground surface of the cooling roll 15 provides uniformity as a whole despite local unevenness, alleviating the influence of partial defects if any. As a result, the melt paddle 11a is stabilized.
A proper effect of suppressing the vibration of the melt paddle 11a by fine linear scratches on the surface of the cooling roll 15 would not be obtained unless the temperature of the nozzle 14 is kept constant to provide the melt paddle 11a with as small temperature distribution as possible. In other words, a sufficient effect of suppressing the vibration of the melt paddle 11a cannot be obtained by merely forming fine linear scratches on the surface of the cooling roll 15, or by merely keeping the temperature of the melt nozzle 14 constant. Only a combination of both means can provide a proper effect of suppressing the vibration of the melt paddle 11a. Because the vibration of the melt paddle 11a would occur even by slight variations of conditions, it is not easy to find a means for suppressing it. By a combination of fine linear scratches formed on the surface of the cooling roll 15 and the reduced temperature distribution of the melt nozzle 14, the present invention has succeeded in meeting both difficult requirements of reducing eddy current loss by the wave-like undulations acting to make magnetic domains smaller, and preventing increase in hysteresis loss by suppressing the amplitude of transverse troughs in the wave-like undulations.
The resultant Fe-based soft-magnetic alloy ribbon may be heat-treated. The heat treatment is preferably conducted at a temperature of 350-650° C. in an inert gas such as Ar, nitrogen, etc. The heat treatment time is usually 24 hours or less, preferably 5 minutes to 4 hours. The rapidly quenched Fe-based soft-magnetic alloy ribbon of the present invention may be coated with SiO2, MgO, Al2O3, etc., or subject to such treatments as a chemical conversion treatment, an anodic oxidation treatment, etc., if necessary, to increase its insulation.
[4] Core
The core of the present invention is formed by laminating or winding the quenched, Fe-based soft-magnetic alloy ribbon. Because the quenched, Fe-based soft-magnetic alloy ribbon of the present invention has eddy current loss and hysteresis loss both reduced, a core formed thereby has low core loss. The core is heat-treated in an inert gas such as a nitrogen gas, Ar, etc., in vacuum, or in the air. With a magnetic field applied in a magnetic path direction of the core during the heat treatment, the resultant core has a high squareness ratio, high apparent power, and low core loss. To obtain a high squareness ratio, a magnetic field having such intensity as to magnetically saturate the core is applied. The intensity of the magnetic field is preferably 400 A/m or more, more preferably 800 A/m or more. The magnetic field applied is mostly a DC magnetic field, but an AC magnetic field may be used. The heat treatment may be carried out by a single step or by multiple steps.
The present invention will be explained in further detail by Examples below, without intention of restricting the present invention thereto.
In the apparatus shown in
During the production of the Fe-based amorphous alloy ribbon, a wire brush roll 11 of stainless steel wires of 0.06 mm in diameter was rotated at a peripheral speed of 3 m/s in an opposite direction to the cooling roll 15. Fine linear scratches having an arithmetical mean (average) roughness Ra of 0.6 μm and a maximum roughness depth Rmax of 4.7 μm were formed on a surface of the cooling roll 15 ground by the wire brush roll 11. As a result, the attachment of oxides to the cooling roll 15 was suppressed.
The resultant Fe-based amorphous alloy ribbon exhibited a halo pattern peculiar to the amorphous structure in X-ray diffraction. Wave-like undulations 2 formed on a free surface of the Fe-based amorphous alloy ribbon had continuous troughs 3 in a range of 80% of the ribbon width, the troughs 3 having an average amplitude D of 8.2 mm and an average longitudinal interval L of 2.0 mm, and the average height difference t between the troughs 3 and the ridges 4 being 3.0 μm or less.
An Fe-based amorphous alloy ribbon was produced under the same conditions as in Example 1, except that a heated carbon dioxide gas was not ejected from a heating nozzle 21. This Fe-based amorphous alloy ribbon exhibited a halo pattern in X-ray diffraction, and wave-like undulations 2 formed on its free surface had continuous troughs 3 in a range of 80% of the ribbon width. Though the wave-like undulations 2 had substantially the same average longitudinal interval L and average height difference t between troughs 3 and ridges 4 as those of Example 1, the average amplitude D of the troughs 3 was as extremely large as 24.0 mm.
An Fe-based amorphous alloy ribbon was produced under the same conditions as in Example 1, except for using no wire brush roll 11. This Fe-based amorphous alloy ribbon exhibited a halo pattern in X-ray diffraction, and wave-like undulations 2 formed on its free surface had continuous troughs 3 in a range of 80% of the ribbon width. Because oxides were attached to the cooling roll 15 during production for a long period of time, extremely large wave-like undulations 2 were formed on a free surface of the Fe-based amorphous alloy ribbon, their average longitudinal interval L being 2.1 mm, the average height difference t between troughs 3 and ridges 4 being 7.3 μm, and the average amplitude D of the troughs 3 being 26.4 mm.
The Fe-based amorphous alloy ribbons of Example 1 and Comparative Examples 1 and 2 were heat-treated at 350° C. for 60 minutes in a longitudinal magnetic field of 1500 A/m. A single sheet sample of each heat-treated, Fe-based amorphous alloy ribbon was measured with respect to a DC B-H loop, to determine hysteresis loss Ph1.3/50 at 1.3 T and 50 Hz. Further, the core loss P1.3/50 and exciting power S1.3/50 of the single sheet sample were measured at 1.3 T and 50 Hz by a single sheet tester (apparatus for evaluating the magnetic properties of a single sheet). The results are shown in Table 1.
As is clear from Table 1, the Fe-based amorphous alloy ribbon of Example 1 having smaller wave-like undulations 2, in which the average amplitude D of the troughs 3 was as small as 8.2 mm, had hysteresis loss Ph1.3/50 of 0.033 W/kg, core loss P1.3/50 of 0.053 W/kg, and exciting power S1.3/50 of 0.070 VA/kg, smaller than those of the Fe-based amorphous alloy ribbons of Comparative Examples 1 and 2.
A ceramic-made nozzle 14 having a slit-shaped opening of 30 mm in length and 0.5-0.7 mm in width was used in the apparatus shown in
During the production of the Fe-based amorphous alloy ribbon, a wire brush roll 11 having stainless steel wires of 0.03 mm in diameter was rotated at a peripheral speed of 4 m/s in an opposite direction to the cooling roll 15. A surface of the cooling roll 15 ground by the wire brush roll 11 had fine linear scratches having an average roughness Ra of 0.25 μm and maximum roughness depth Rmax of 2.7 μm. As a result, the attachment of oxides to the cooling roll 15 was suppressed.
Each Fe-based amorphous alloy ribbon was produced under the same conditions as in Examples 2-19, except that a heated carbon dioxide gas was not ejected from a heating nozzle 21. During the production of the Fe-based amorphous alloy ribbon, a transverse temperature distribution in the melt nozzle 14 was as large as 1200° C.±30° C.
During the production of the Fe-based amorphous alloy ribbon, a wire brush roll 11 having stainless steel wires of 0.05 mm in diameter was rotated at a peripheral speed of 5 m/s in an opposite direction to the cooling roll 15. A surface of the cooling roll 15 ground by the wire brush roll 11 had fine linear scratches having an average roughness Ra of 0.4 μm and maximum roughness depth Rmax of 2.3 μm. As a result, the attachment of oxides to the cooling roll 15 was suppressed.
Any of the Fe-based amorphous alloy ribbons produced in Examples 2-19 and Comparative Examples 3-6 exhibited a halo pattern peculiar to the amorphous structure in X-ray diffraction. Each Fe-based amorphous alloy ribbon had the thickness T shown in Table 2. Wave-like undulations 2 formed on a free surface of each Fe-based amorphous alloy ribbon had continuous troughs 3 in a range corresponding to 100% of the ribbon width, and the troughs shown in Table 2 had an average amplitude D of 8.9 mm, an average longitudinal interval L of 2.5 mm, and an average t/T ratio of 0.1.
Each Fe-based amorphous alloy ribbon of Examples 2-19 and Comparative Examples 3-6 was heat-treated at 350° C. for 60 minutes in a longitudinal magnetic field of 1000 A/m. A single sheet sample of each heat-treated Fe-based amorphous alloy ribbon was measured with respect to a DC B-H loop, to determine hysteresis loss Ph1.36/50 at 1.3 T and 50 Hz. Further, the core loss P1.3/50 and exciting power S1.3/50 of each single sheet sample at 1.3 T and 50 Hz were measured by a single sheet tester. The results are shown in
Table 3.
As is clear from Table 3, the Fe-based amorphous alloy ribbons of
Examples 2-19 were smaller than those of Comparative Examples 3-6 in both core loss P1.3/50 and exciting power S1.3/50. This is because the Fe-based amorphous alloy ribbons of Examples 2-19 had smaller hysteresis losses Ph1.3/50 than those of the Fe-based amorphous alloy ribbons of Comparative Examples 3-6.
A ceramic-made melt nozzle 14 having a slit-shaped opening of 30 mm in length and 0.5-0.7 mm in width was used in the apparatus shown in
During the production of each Fe-based amorphous alloy ribbon, a wire brush roll 11 having stainless steel wires of 0.04 mm in diameter was rotated at a peripheral speed of 4 m/s in an opposite direction to the cooling roll 15. A surface of the cooling roll 15 ground by the wire brush roll 11 had fine linear scratches having an average roughness Ra of 0.5 μm and a maximum roughness depth Rmax of 2.5 μm. As a result, the attachment of oxides to the cooling roll 15 was suppressed.
Each Fe-based amorphous alloy ribbon was produced under the same conditions as in Examples 20-39, except that a heated carbon dioxide gas was not ejected from the heating nozzle 21. During the production of each Fe-based amorphous alloy ribbon, a transverse temperature distribution in the melt nozzle 14 was as large as 1200° C.±35° C.
During the production of each Fe-based amorphous alloy ribbon, a wire brush roll 11 having stainless steel wires of 0.08 mm in diameter was rotated at a peripheral speed of 5 m/s in an opposite direction to the cooling roll 15. A surface of the cooling roll 15 ground by the wire brush roll 11 had fine linear scratches having an average roughness Ra of 0.7 μm and a maximum roughness depth Rmax of 3.9 μm. As a result, the attachment of oxides to the cooling roll 15 was suppressed.
Any of the Fe-based amorphous alloy ribbons produced in Examples 20-39 and Comparative Examples 7-10 exhibited a halo pattern peculiar to the amorphous structure in X-ray diffraction. Each Fe-based amorphous alloy ribbon had the thickness T shown in Table 4. Wave-like undulations 2 on a free surface of each Fe-based amorphous alloy ribbon had continuous troughs 3 in a range corresponding to 95% of the ribbon width, the troughs 3 shown in Table 4 having an average amplitude D of 9.0 mm, an average longitudinal interval L of 2.9 mm, and an average t/T ratio of 0.1.
Each Fe-based amorphous alloy ribbon of Examples 20-39 and Comparative Examples 7-10 was heat-treated at 350° C. for 60 minutes in a longitudinal magnetic field of 1000 A/m. X-ray diffraction revealed that crystal peaks corresponding to a bcc-Fe phase were observed in each heat-treated Fe-based amorphous alloy ribbon, indicating that its amorphous phase became less than 50%. The average crystal grain size determined from the half width of the bcc-Fe crystal peak by a Scherrer's equation was 30 nm or less.
A single sheet sample of each heat-treated Fe-based amorphous alloy ribbon was measured with respect to a DC B-H loop to determine hysteresis loss Ph1.3/50 at 1.3 T and 50 Hz. Further, the core loss P1.3/50 and exciting power S1.3/50 of each single sheet sample at 1.3 T and 50 Hz were measured by a single sheet tester. The results are shown in Table 5.
As is clear from Table 5, the core losses P1.3/50 and exciting powers S1.3/50 of the Fe-based amorphous alloy ribbons of Examples 20-39 were smaller than those of the Fe-based amorphous alloy ribbons of Comparative Examples 7-10. This is because the Fe-based amorphous alloy ribbons of Examples 20-39 were smaller in hysteresis loss Ph1.3/50 than the Fe-based amorphous alloy ribbons of Comparative Examples 7-10.
A ceramic-made melt nozzle 14 having a slit-shaped opening of 25 mm in length and 0.6 mm in width was used in the apparatus shown in
During the production of the Fe-based amorphous alloy ribbon, a wire brush roll 11 having stainless steel wires of 0.09 mm in diameter was rotated at a peripheral speed of 6 m/s in an opposite direction to the cooling roll 15. A surface of the cooling roll 15 ground by the wire brush roll 11 had fine linear scratches having an average roughness Ra of 1 μm and a maximum roughness depth Rmax of 5 μm. As a result, the attachment of oxides to the cooling roll 15 was suppressed.
The resultant Fe-based amorphous alloy ribbon exhibited a halo pattern peculiar to the amorphous structure in X-ray diffraction. Wave-like undulations 2 on a free surface of the Fe-based amorphous alloy ribbon had continuous troughs 3 in a range corresponding to 80% of the ribbon width, the troughs 3 having an average amplitude D of 7.4 mm and an average longitudinal interval L of 2.0 mm, and the average height difference t between the troughs 3 and ridges 4 being 3.0 μm or less.
This Fe-based amorphous alloy ribbon was wound to produce a wound core of Example 40 having outer diameter of 75 mm and an inner diameter of 70 mm. While applying a magnetic field of 1000 A/m in a magnetic path direction, it was heat-treated at 330° C. for 60 minutes. Each of the temperature-elevating speed and the cooling speed was 5° C./minute. The DC B-H loop of the heat-treated wound core was measured to determine hysteresis loss Ph1.3/50 at 1.3 T and 50 Hz. Evaluation of AC magnetic properties revealed that the wound core had a core loss of 0.055 W/kg and an exciting power S1.3/50 of 0.073 VA/kg at 1.3 T and 50 Hz.
Using an Fe-based amorphous alloy ribbon produced under the same conditions as in Example 40 except that a heated carbon dioxide gas was not ejected from the heating nozzle 21, a wound core was produced. Wave-like undulations 2 on a free surface of the Fe-based amorphous alloy ribbon had troughs 3 having an average amplitude D of 24.6 mm. The wound core had a core loss P1.3/50 of 0.103 W/kg and an exciting power S1.3/50 of 0.123 VA/kg at 1.3 T and 50 Hz. This indicates that wound cores would have large core loss and exciting power if the requirements of the present invention were not met.
Because the quenched, Fe-based soft-magnetic alloy ribbon of the present invention has wave-like undulations on a free surface, the wave-like undulations having transverse troughs arranged at substantially constant intervals in a longitudinal direction, and the troughs having an average amplitude D of 20 mm or less, it has reduced eddy current loss and suppressed hysteresis loss, thereby exhibiting extremely low core loss. Cores obtained by laminating or winding such quenched, Fe-based soft-magnetic alloy ribbons have high efficiency because of low core loss, and low noise because of low apparent power, suitable for distribution transformers, various reactors, choke coils, magnetic switches, etc.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-016017 | Jan 2011 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2012/051808 | 1/27/2012 | WO | 00 | 7/25/2013 |
