Voltage-dependent non-linear resistance ceramic composition

DESCRIPTION
1. Technical Field
The present invention relates to a voltage dependent non-linear resistance ceramic composition for use in surge absorbing, noise elimination and a measure against undesirable electric changing in various electric apparatuses and electronic apparatuses.
2. Background Art
Heretofore, in various electric apparatuses and electronic apparatuses, in order to absorb extraordinary high voltage, elimination of noise, elimination of arc, and the like, SiC baristors or varistors of ZnO system having a voltage-dependent non-linear resistance characteristics are used. Voltage-current characteristic of such baristors can be approximately represented by the following equation:
I=(V/C).sup..alpha.,
wherein I is current, V is voltage, C is a constant proper for the baristor, and .alpha. is a voltage non-linearity exponent.
The .alpha. of the SiC baristor is about 2-7, and for the ZnO system baristor there is ones that reaching 50. Though such baristors has superior characteristic for absorbing relatively high voltage called surge, for voltages lower than baristor voltage (for instance, absorption of noise) almost no effect is represented since its dielectric constant is low and its inherent capacitance is small, and their dielectric loss tan .delta. are so large as 5-10%.
On the other hand, for elimination of low voltage noise, static electricity, or the like, by appropriately selecting composition and firing condition, semiconductor ceramic capacitors having apparent dielectric constant of about 5.times.10.sup.4 -6.times.10.sup.4 and tan .delta. of about 1% are utilized.
However, these semiconductor ceramic capacitor is liable to be destroyed or become to be non-functional as capacitors when extraordinary high voltage such as surge is impressed thereon or a current above a certain limit is impressed on the element. For such reason, in the electric apparatuses or electronic apparatuses, for the purpose of both the absorbing of high voltage surge and the elimination of low voltage noise, the baristors are used being combined with capacitors and other component (for instance, coil), and for instance, a noise filter has such configuration.
FIG. 1 shows general noise filter circuit, FIG. 2 shows conventional noise filter circuit constituted by combining a baristor, capacitors and a coil, and 1 is the coil, 2 are the capacitors and 3 is the baristor.
When a noise input A shown in FIG. 5 is impressed on these circuits, output characteristic from general noise filter circuit of FIG. 1 is such as C of FIG. 5, and noise is not eliminated sufficiently. Output characteristic from the conventional noise filter circuit including a baristor shown in FIG. 2 is such as B of FIG. 5, and though noise is eliminated, such configuration has a shortcoming that it has large number of components in the inside of the apparatus and besides is contrary to tendency of miniaturization of the apparatus.
Accordingly, an electronic component, which absorbs extrraordinary high voltage, can eliminate low voltage, such as noise and has small number of components, and capable of miniaturization, is demanded.
SUMMARY OF THE INVENTION
Accordingly, the present invention intends to provide a voltage-dependent non-linear resistance ceramic composition comprising SrTiO.sub.3, Sr.sub.1-x Ba.sub.x TiO.sub.3 (0.001.ltoreq.x.ltoreq.0.300) or Sr.sub.1-x Ca.sub.x TiO.sub.3 (0.001.ltoreq.x.ltoreq.0.300) as host material, including 0.001-2.000 mol % of Y.sub.2 O.sub.3 as metal oxide for semiconductorization acceleration, and including 0.001-3.000 mol % of oxide(s) of at least one metal selected from the group consisting of Co.sub.2 O.sub.3, CuO, Ag.sub.2 O, Al.sub.2 O.sub.3, ZrO.sub.2, BaO, SiO.sub.2, MgO, B.sub.2 O.sub.3, MnO.sub.2, NiO, MoO.sub.3, BeO, Fe.sub.2 O.sub.3, Li.sub.2 O, Cr.sub.2 O.sub.3, PbO, CaO, TiO.sub.2, P.sub.2 O.sub.5, Sb.sub.2 O.sub.3 and V.sub.2 O.sub.5, which segregates at grain boundary to make the grain boundary to high resistance.

BRIEF EXPLANATION OF THE DRAWING
FIG. 1 is a circuit diagram of a general noise filter.
FIG. 2 is a circuit diagram of a noise filter using the conventional varistors and the capacitors.
FIG. 3 is a sectional view of an element using voltage dependent non-linear resistance ceramic composition in accordance with the present invention.
FIG. 4 is a circuit diagram of a noise filter using the voltage dependent non-linear resistance ceramic composition in accordance with the present invention.
FIG. 5 is a characteristic chart showing situation of input noise and output in accordance with circuit of noise filters of the present invention and the prior art.
FIG. 6 is a characteristic diagram showing relation between Sr/Ti ratio and specific resistance.
FIG. 7 is a characteristic diagram showing relation between Sr/Ti ratio and tan .delta..

THE BEST MODE FOR EMBODYING THE INVENTION
As a result of accumulation of various experiments, the inventors made a voltage dependent non-linear resistance ceramic composition in a quite different system from the conventional composition by making SrTiO.sub.3, Sr.sub.1-x Ba.sub.x TiO.sub.3 (0.001.ltoreq.x.ltoreq.0.300) or Sr.sub.1-x Ca.sub.x TiO.sub.3 (0.001.ltoreq.x.ltoreq.0.300) as host material, and Y.sub.2 O.sub.3 as semiconductorization accelerating agent, and by further adding Co.sub.2 O.sub.3 and CuO, and further adding if necessary an appropriate amount of additive. Hereafter, the present invention is described with respect to embodiments, with reference to the accompanying drawings.
<EXAMPLE 1>
After measuring SrCO.sub.3 and TiO.sub.2 in a manner that SrTiO.sub.3 having Sr/Ti atom ratio of 0.98 is obtained, and they are blended for 15 hours in wet method in a ball-mill or the like. And after driving the mixture is then dried, and then is grounded. Thereafter the grounded powder is calcinated for 3 hours at 1100.degree. C. in the air and again grounded to produce SrTiO.sub.3 powder.
Next, SrTiO.sub.3, Y.sub.2 O.sub.3, Co.sub.2 O.sub.3, CuO, Ag.sub.2 O and Al.sub.2 O.sub.3 are measured and blended in an ingredient component as shown in the following Table 1.
TABLE 1__________________________________________________________________________Composition ratio First Second Third Fourth FifthSample component component component component componentNo. SrTiO.sub.3 (mol %) Y.sub.2 O.sub.3 (mol %) Co.sub.2 O.sub.3 (mol %) CuO (mol %) Additive mol %__________________________________________________________________________ 1* 99.999 0.001 0.000 0.000 -- 0.000 2* 99.900 0.100 0.000 0.000 -- 0.000 3* 99.000 1.000 0.000 0.000 -- 0.000 4* 98.000 2.000 0.000 0.000 -- 0.000 5* 97.000 3.000 0.000 0.000 -- 0.000 6* 99.998 0.001 0.001 0.000 -- 0.000 7 99.889 0.100 0.010 0.001 -- 0.000 8 99.199 0.300 0.500 0.001 -- 0.000 9 97.999 1.000 1.000 0.001 -- 0.00010 96.499 1.500 2.000 0.001 -- 0.000 11* 95.499 1.500 3.000 0.001 -- 0.00012 99.988 0.001 0.001 0.010 -- 0.00013 99.889 0.010 0.001 0.100 -- 0.00014 99.489 0.010 0.001 0.500 -- 0.00015 97.999 1.000 0.001 1.000 -- 0.000 16* 96.999 1.000 0.001 2.000 -- 0.00017 99.700 0.100 0.100 0.100 -- 0.00018 99.300 0.100 0.300 0.300 -- 0.00019 98.600 0.100 0.300 1.000 -- 0.00020 98.600 0.100 1.000 0.300 -- 0.00021 97.700 0.300 1.500 0.500 -- 0.00022 97.200 1.000 1.000 0.800 -- 0.00023 96.000 2.000 1.000 1.000 -- 0.00024 99.699 0.100 0.100 0.100 Ag.sub.2 O 0.00125 99.699 0.100 0.100 0.100 Al.sub.2 O.sub.3 0.00126 99.490 0.100 0.300 0.100 Ag.sub.2 O 0.01027 99.200 0.100 0.300 0.100 Al.sub.2 O.sub.3 0.30028 98.250 0.300 0.300 0.150 Ag.sub.2 O 1.00029 97.150 0.500 0.300 0.050 Al.sub.2 O.sub.3 2.00030 95.900 0.500 0.500 0.100 Al.sub.2 O.sub.3 3.000 31* 94.950 0.800 0.700 0.050 Ag.sub.2 O 3.50032 99.699 0.100 0.100 0.050 Ag.sub.2 O 0.001 Al.sub.2 O.sub.3 0.05033 99.240 0.100 0.100 0.050 Ag.sub.2 O 0.010 Al.sub.2 O.sub.3 0.50034 98.650 0.100 0.100 0.050 Ag.sub.2 O 0.100 Al.sub.2 O.sub.3 1.00035 97.350 0.300 0.200 0.100 Ag.sub.2 O 0.050 Al.sub.2 O.sub.3 2.00036 96.840 0.300 0.300 0.050 Ag.sub.2 O 0.010 Al.sub.2 O.sub.3 2.500 37* 95.800 0.500 0.200 0.100 Ag.sub.2 O 0.200 Al.sub.2 O.sub.3 3.200__________________________________________________________________________ Marked * are comparison examples which are outside the claimed scope.
Further, the mixture is blended in a ball mill for 20 hours, dried and then grounded. And subsequently, by adding 10-15 weight % of organic binder such as polyvinylalchohol the powder is granulated, and formed in a shape and size of 10 mm diameter and 1 mm thick disk by application of a pressing force of about 1.0 t/cm.sup.2.
Then, the press-formed disk is fired for 4 hours at a temperature of 1380.degree. C. in a reducing atmosphere of N.sub.2 (90% in volume)+H.sub.2 (10% in volume). It is further heat treated at 1100.degree. C. for 4 hours in the air. The disk shaped sintered body 1 shown in FIG. 1 obtained in the above-mentioned process has almost the same component ratio as that of the starting materials.
On both faces of the sintered body 1, electrodes 2 and 3 are formed by applying conductive paint containing silver powder or the like and subsequently burning it.
Characteristics of the element obtained in the above-mentioned manner is shown in Table 2.
TABLE 2______________________________________SampleNo. V.sub.1 mA /.sub.mm (V) .alpha. .epsilon. tan .multidot. .delta. (%)______________________________________ 1* 83.0 1.3 1.0 .times. 10.sup.6 94.0 2* 85.5 1.9 1.4 .times. 10.sup.6 91.2 3* 82.0 2.8 1.2 .times. 10.sup.6 87.1 4* 94.0 3.5 7.6 .times. 10.sup.5 77.0 5* 103.7 4.4 3.2 .times. 10.sup.5 70.8 6* 50.6 6.0 1.9 .times. 10.sup.4 6.4 7 37.3 7.9 3.2 .times. 10.sup.4 3.8 8 33.8 8.0 3.9 .times. 10.sup.4 3.1 9 31.7 8.6 4.5 .times. 10.sup.4 3.010 35.4 8.1 5.2 .times. 10.sup.4 3.1 11* 55.1 7.2 9.4 .times. 10.sup.4 6.012 42.5 8.2 4.9 .times. 10.sup.4 4.013 43.8 8.9 5.8 .times. 10.sup.4 3.814 58.2 9.2 4.0 .times. 10.sup.4 3.515 70.4 10.3 3.3 .times. 10.sup.4 3.1 16* 210.3 10.0 3.1 .times. 10.sup.3 1.417 35.2 8.0 5.2 .times. 10.sup.4 3.518 30.7 8.7 5.6 .times. 10.sup.4 3.419 47.1 9.3 5.0 .times. 10.sup.4 3.020 43.3 9.5 4.7 .times. 10.sup.4 3.121 39.9 9.7 4.6 .times. 10.sup.4 3.022 37.8 10.2 4.8 .times. 10.sup.4 3.023 41.0 10.5 4.4 .times. 10.sup.4 3.024 42.3 9.3 6.1 .times. 10.sup.4 2.425 40.7 8.7 5.2 .times. 10.sup.4 3.326 44.4 9.9 6.3 .times. 10.sup.4 2.227 42.3 9.1 5.0 .times. 10.sup.4 3.128 57.2 10.7 4.1 .times. 10.sup.4 1.929 48.1 10.0 4.2 .times. 10.sup.4 3.030 50.3 9.8 3.9 .times. 10.sup.4 2.9 31* 319.6 10.1 4.2 .times. 10.sup.3 1.532 39.9 9.4 6.9 .times. 10.sup.4 1.933 44.3 9.9 6.2 .times. 10.sup.4 1.834 49.7 10.2 4.9 .times. 10.sup.4 1.735 50.8 10.4 4.3 .times. 10.sup.4 1.636 61.3 10.8 4.0 .times. 10.sup.4 1.6 37* 104.0 9.3 5.1 .times. 10.sup.3 3.9______________________________________ Marked * are comparison examples which are outside the claimed scope.
Herein, assessment of characteristics of the elements as varistor can be made by .alpha. and C in a voltage-current characteristic equation:
I=(V/C).sup..alpha.
wherein I is current, V is voltage, C is a constant proper to the varistor and .alpha. is a non-linearity exponent. In the present invention, since accurate measurement of C is difficult, characteristic assessment as varistor is made by the value of varistor voltage for unit thickness when 1 mA of varistor current is made to flow (hereinafter such varister voltage is called as V.sub.1 mA/mm), and by the value of .alpha.=1/log (V.sub.10 mA/V.sub.1 mA), wherein V.sub.10 mA is a varistor voltage when a varistor current of 10 mA is flowed and V.sub.1 mA is a varistor voltage when varistor current of 1 mA is flowed.
And characteristic assessment as the capacitors are made by a dielectric constant .epsilon. and dielectric loss tan .delta. at a measurement frequency of 1 KHz.
<EXAMPLE 2>
SrCO.sub.3, BaCO.sub.3 and TiO.sub.2 are measured and blended in a manner to make Sr.sub.0.9 Ba.sub.0.1 TiO.sub.3, and blended and grounded in a ball mill in a wet method for 15 hours. And the mixture is dried and ground, and then fired at 1200.degree. C. for 3 hours, and further grounded thereby to prepare powder of Sr.sub.0.9 Ba.sub.0.1 TiO.sub.3. Then, Y.sub.2 O.sub.3, Co.sub.2 O.sub.3, CuO, Ag.sub.2 O and Al.sub.2 O.sub.3 are measured added to the above-mentioned powder of Sr.sub.0.9 Ba.sub.0.1 TiO.sub.3, in a manner to make the composition ratio shown Table 3.
TABLE 3__________________________________________________________________________Composition ratio Firstcomponent Second Third Fourth FifthSample Sr.sub.0.9 Ba.sub.0.1 TiO.sub.3 component component component componentNo. (mol %) Y.sub.2 O.sub.3 (mol %) Co.sub.2 O.sub.3 (mol %) CuO (mol %) Additive mol %__________________________________________________________________________ 1* 99.999 0.001 0 0 -- -- 2* 99.900 0.100 0 0 -- -- 3* 99.000 1.000 0 0 -- -- 4* 98.000 2.000 0 0 -- -- 5* 97.000 3.000 0 0 -- -- 6* 99.998 0.001 0.001 0 -- -- 7 99.889 0.100 0.010 0.001 -- -- 8 99.199 0.300 0.500 0.001 -- -- 9 97.999 1.000 1.000 0.001 -- --10 96.499 1.500 2.000 0.001 -- -- 11* 95.499 1.500 3.000 0.001 -- --12 99.988 0.001 0.001 0.001 -- --13 99.889 0.010 0.001 0.100 -- --14 99.489 0.010 0.001 0.500 -- --15 97.999 1.000 0.001 1.000 -- -- 16* 96.999 1.000 0.001 2.000 -- --17 99.700 0.100 0.100 0.100 -- --18 99.300 0.100 0.300 0.300 -- --19 98.600 0.100 0.300 1.000 -- --20 98.600 0.100 1.000 0.300 -- --21 97.700 0.300 1.500 0.500 -- --22 97.200 1.000 1.000 0.800 -- --23 96.000 2.000 1.000 1.000 -- --24 99.699 0.100 0.100 0.100 Ag.sub.2 O 0.00125 99.699 0.100 0.100 0.100 Al.sub.2 O.sub.3 0.00126 99.490 0.100 0.300 0.100 Ag.sub.2 O 0.01027 99.200 0.100 0.300 0.100 Al.sub.2 O.sub.3 0.30028 98.250 0.300 0.300 0.150 Ag.sub.2 O 1.00029 97.150 0.500 0.300 0.050 Al.sub.2 O.sub.3 2.00030 95.900 0.500 0.500 0.100 Al.sub.2 O.sub.3 3.000 31* 94.950 0.800 0.700 0.050 Ag.sub.2 O 3.50032 99.699 0.100 0.100 0.050 Ag.sub.2 O 0.001 Al.sub.2 O.sub.3 0.05033 99.240 0.100 0.100 0.050 Ag.sub.2 O 0.010 Al.sub.2 O.sub.3 0.50034 98.650 0.100 0.100 0.050 Ag.sub. 2 O 0.100 Al.sub.2 O.sub.3 1.00035 97.350 0.300 0.200 0.100 Ag.sub.2 O 0.050 Al.sub.2 O.sub.3 2.00036 96.840 0.300 0.300 0.050 Ag.sub.2 O 0.010 Al.sub.2 O.sub.3 2.500 37* 95.800 0.500 0.200 0.100 Ag.sub.2 O 0.200 Al.sub.2 O.sub.3 3.200__________________________________________________________________________ Marked * are comparison examples which are outside the claimed scope.
The above-mentioned starting material is mixed, press-formed and fired in the same condition way and conditions as of EXAMPLE 1 to make the similar element as that of EXAMPLE 1. The characteristics of the element are measured in the same way as that of EXAMPLE 1, and the measured results are shown in Table 4.
TABLE 4______________________________________SampleNo. V.sub.1mA /.sub.mm (V) .alpha. .epsilon. tan .delta. (%)______________________________________ 1* 85.0 1.3 1.0 .times. 10.sup.6 90.9 2* 86.9 1.8 1.4 .times. 10.sup.6 84.5 3* 84.5 2.0 1.2 .times. 10.sup.6 82.0 4* 103.0 2.9 7.5 .times. 10.sup.5 80.0 5* 112.1 3.8 1.0 .times. 10.sup.5 71.8 6* 57.4 4.7 1.6 .times. 10.sup.4 9.2 7 38.2 7.2 3.3 .times. 10.sup.4 3.9 8 36.3 7.3 3.8 .times. 10.sup.4 3.3 9 33.8 7.8 4.5 .times. 10.sup.4 3.210 37.7 8.0 4.8 .times. 10.sup.4 3.1 11* 61.9 5.7 7.0 .times. 10.sup.4 10.012 44.4 7.7 4.5 .times. 10.sup.4 3.913 45.7 7.9 5.0 .times. 10.sup.4 3.814 60.4 8.1 4.3 .times. 10.sup.4 3.715 71.3 9.2 3.9 .times. 10.sup.4 3.2 16* 235.3 8.1 2.8 .times. 10.sup.3 1.917 39.1 7.2 4.8 .times. 10.sup.4 3.418 32.9 7.5 5.0 .times. 10.sup.4 3.419 49.8 7.9 5.2 .times. 10.sup.4 3.320 40.8 8.8 4.7 .times. 10.sup.4 3.021 38.3 8.8 4.6 .times. 10.sup.4 3.022 33.5 8.9 4.4 .times. 10.sup.4 3.023 39.9 9.1 4.0 .times. 10.sup.4 3.024 43.5 9.2 5.3 .times. 10.sup.4 2.525 44.6 8.7 4.8 .times. 10.sup.4 3.226 59.8 9.7 5.1 .times. 10.sup.4 2.427 48.7 9.0 4.7 .times. 10.sup.4 3.228 61.8 10.5 4.0 .times. 10.sup.4 2.429 50.3 9.5 4.0 .times. 10.sup.4 3.530 52.1 9.7 2.1 .times. 10.sup.4 3.1 31* 309.0 9.9 3.3 .times. 10.sup.3 1.932 42.5 9.5 5.7 .times. 10.sup.4 1.933 48.1 9.7 5.5 .times. 10.sup.4 1.834 52.0 9.9 3.1 .times. 10.sup.4 1.835 54.8 10.0 3.3 .times. 10.sup.4 1.936 63.7 10.3 3.9 .times. 10.sup.4 2.3 37* 114.0 9.1 2.1 .times. 10.sup.3 5.0______________________________________
<EXAMPLE 3>
SrCO.sub.3, CaCO.sub.3 and TiO.sub.2 are measured and blended in a manner to make Sr.sub.0.9 Ca.sub.0.1 TiO.sub.3, and blended and grounded in a ball mill in a wet method for 15 hours. And the mixture is dried and ground, and then fired at 1200.degree. C. for 3 hours, and further grounded thereby to prepare powder of Sr.sub.0.9 Ca.sub.0.1 TiO.sub.3. Then, Y.sub.2 O.sub.3, Co.sub.2 O.sub.3, CuO, Ag.sub.2 O and Al.sub.2 O.sub.3 are measured added to the above-mentioned powder of Sr.sub.0.9 Ca.sub.0.1 TiO.sub.3, in a manner to make the composition ratio shown Table 5.
TABLE 5__________________________________________________________________________Composition ratio First Second Third Fourth FifthSample component component component component componentNo. Sr.sub.0.9 Ca.sub.0.1 TiO.sub.3 (mol %) Y.sub.2 O.sub.3 (mol %) Co.sub.2 O.sub.3 (mol %) CuO (mol %) Additive mol %__________________________________________________________________________ 1* 99.999 0.001 0 0 -- -- 2* 99.900 0.100 0 0 -- -- 3* 99.000 1.000 0 0 -- -- 4* 98.000 2.000 0 0 -- -- 5* 97.000 3.000 0 0 -- -- 6* 99.998 0.001 0.001 0 -- -- 7 99.889 0.100 0.010 0.001 -- -- 8 99.199 0.300 0.500 0.001 -- -- 9 97.999 1.000 1.000 0.001 -- --10 96.499 1.500 2.000 0.001 -- -- 11* 95.499 1.500 3.000 0.001 -- --12 99.988 0.001 0.001 0.001 -- --13 99.889 0.010 0.001 0.100 -- --14 99.489 0.010 0.001 0.500 -- --15 97.999 1.000 0.001 1.000 -- -- 16* 96.999 1.000 0.001 2.000 -- --17 99.700 0.100 0.100 0.100 -- --18 99.300 0.100 0.300 0.300 -- --19 98.600 0.100 0.300 1.000 -- --20 98.600 0.100 1.000 0.300 -- --21 97.700 0.300 1.500 0.500 -- --22 97.200 1.000 1.000 0.800 -- --23 96.000 2.000 1.000 1.000 -- --24 99.699 0.100 0.100 0.100 Ag.sub.2 O 0.00125 99.699 0.100 0.100 0.100 Al.sub.2 O.sub.3 0.00126 99.490 0.100 0.300 0.100 Ag.sub.2 O 0.01027 99.200 0.100 0.300 0.100 Al.sub.2 O.sub.3 0.30028 98.250 0.300 0.300 0.150 Ag.sub.2 O 1.00029 97.150 0.500 0.300 0.050 Al.sub.2 O.sub.3 2.00030 95.900 0.500 0.500 0.100 Al.sub.2 O.sub.3 3.000 31* 94.950 0.800 0.700 0.050 Ag.sub.2 O 3.50032 99.699 0.100 0.100 0.050 Ag.sub.2 O 0.001 Al.sub.2 O.sub.3 0.05033 99.240 0.100 0.100 0.050 Ag.sub.2 O 0.010 Al.sub. 2 O.sub.3 0.50034 98.650 0.100 0.100 0.050 Ag.sub.2 O 0.100 Al.sub.2 O.sub.3 1.00035 97.350 0.300 0.200 0.100 Ag.sub.2 O 0.050 Al.sub.2 O.sub.3 2.00036 96.840 0.300 0.300 0.050 Ag.sub.2 O 0.010 Al.sub.2 O.sub.3 2.500 37* 95.800 0.500 0.200 0.100 Ag.sub.2 O 0.200 Al.sub.2 O.sub.3 3.200__________________________________________________________________________ Marked * are comparison examples which are outside the claimed scope.
The above-mentioned starting material is mixed, press-formed and fired in the same condition way and conditions as of EXAMPLE 1 to make the similar element as that of EXAMPLE 1. The characteristics of the element are measured in the same way as that of EXAMPLE 1, and the measured results are shown in Table 6.
TABLE 6______________________________________SampleNo. V1mA/mm(V) .alpha. .epsilon. tan .delta. (%)______________________________________ 1* 82.0 1.3 1.1 .times. 10.sup.6 99.0 2* 85.0 1.8 1.5 .times. 10.sup.6 92.4 3* 80.1 2.4 1.3 .times. 10.sup.6 90.1 4* 92.0 3.0 7.7 .times. 10.sup.5 85.7 5* 100.3 4.1 1.3 .times. 10.sup.5 88.1 6* 46.5 5.3 1.7 .times. 10.sup.4 8.17 33.6 7.6 3.4 .times. 10.sup.4 3.88 31.8 7.8 3.9 .times. 10.sup.4 3.19 30.2 7.9 4.7 .times. 10.sup.4 3.110 31.9 8.0 5.2 .times. 10.sup.4 3.1 11* 53.8 6.3 8.4 .times. 10.sup.4 8.912 40.4 7.9 5.2 .times. 10.sup.4 4.013 42.8 8.3 6.1 .times. 10.sup.4 3.714 57.0 8.7 4.7 .times. 10.sup.4 3.615 69.1 9.6 4.3 .times. 10.sup.4 3.1 16* 203.0 7.3 2.1 .times. 10.sup.3 1.117 31.7 7.4 4.9 .times. 10.sup.4 3.418 27.5 7.9 5.5 .times. 10.sup.4 3.419 41.3 8.5 5.4 .times. 10.sup.4 3.220 38.4 8.9 4.9 .times. 10.sup.4 3.221 35.3 9.1 4.8 .times. 10.sup.4 3.122 30.7 9.4 4.8 .times. 10.sup.4 3.123 37.1 9.6 4.4 .times. 10.sup.4 3.124 40.4 9.1 6.5 .times. 10.sup.4 2.825 37.0 8.5 5.7 .times. 10.sup.4 3.526 39.0 9.4 6.9 .times. 10.sup.4 3.027 40.2 9.1 6.1 .times. 10.sup.4 3.428 55.1 10.3 4.8 .times. 10.sup.4 2.829 45.0 9.7 4.7 .times. 10.sup.4 3.230 47.2 9.4 4.3 .times. 10.sup.4 3.3 31* 206.7 9.0 1.9 .times. 10.sup.3 2.932 34.3 9.1 6.8 .times. 10.sup.4 2.933 41.0 9.4 6.2 .times. 10.sup.4 2.834 47.2 9.8 5.1 .times. 10.sup.4 2.735 48.0 9.7 4.4 .times. 10.sup.4 2.836 57.8 9.5 4.3 .times. 10.sup.4 2.7 37* 101.1 8.2 4.9 .times. 10.sup.4 4.0______________________________________ Marked * are comparison examples which are outside the claimed scope.
<EXAMPLE 4>
After measuring SrCO.sub.3 and TiO.sub.2 in a manner that SrTiO.sub.3 having Sr/Ti atom ratio of 0.98 is obtained, and they are blended and ground for 12 hours in wet method in a ball-mill or the like and dried. Then, the mixture is again ground, and thereafter, the ground powder is press-formed into a disk of a size of 80 mm diameter and 50 mm thickness by a pressing force of 1.0 ton/cm.sup.2. The press-formed body then is calcinated at 1200.degree. C. for 4 hours, and further ground by a ball-mill or the like for about 20 hours, thereby to prepare a host material powder of SrTiO.sub.3.
Next, SrTiO.sub.3, Y.sub.2 O.sub.3, Co.sub.2 O.sub.3, CuO, Ag.sub.2 O and ZrO.sub.2, and further, one of B.sub.2 O.sub.3, NiO, MoO.sub.3, BeO, Fe.sub.2 O.sub.3, Al.sub.2 O.sub.3, Li.sub.2 O, Cr.sub.2 O.sub.3, PbO, CaO, TiO.sub.2, P.sub.2 O.sub.5, Sb.sub.2 O.sub.3, V.sub.2 O.sub.5 are measured in a composition ratio shown in Table 7, and press-formed and fired in the same manner as EXAMPLE 1. And the resulted element was measured in the similar conditions as those of EXAMPLE 1, and the results are shown in Table 8.
TABLE 7__________________________________________________________________________Sample Composition ratio (mol %)No. SrTiO.sub.3 Y.sub.2 O.sub.3 Co.sub.2 O.sub.3 CuO Ag.sub.2 O ZrO.sub.2 Additive__________________________________________________________________________ 1* 99.999 0.001 -- -- -- -- -- 2* 99.998 0.001 0.001 -- -- -- -- 3* 99.997 0.001 0.001 0.001 -- -- -- 4* 99.996 0.001 0.001 0.001 0.001 -- -- 5 99.995 0.001 0.001 0.001 0.001 0.001 -- 6 99.986 0.010 0.001 0.001 0.001 0.001 -- 7 99.896 0.100 0.001 0.001 0.001 0.001 -- 8 98.996 1.000 0.001 0.001 0.001 0.001 -- 9 97.996 2.000 0.001 0.001 0.001 0.001 -- 10* 95.996 4.000 0.001 0.001 0.001 0.001 --11 99.397 0.500 0.100 0.001 0.001 0.001 --12 98.497 0.500 1.000 0.001 0.001 0.001 --13 97.497 0.500 2.000 0.001 0.001 0.001 -- 14* 95.497 0.500 4.000 0.001 0.001 0.001 --15 99.298 0.500 0.100 0.100 0.001 0.001 --16 98.398 0.500 0.100 1.000 0.001 0.001 -- 17* 97.398 0.500 0.100 2.000 0.001 0.001 --18 99.199 0.500 0.100 0.100 0.100 0.001 --19 98.299 0.500 0.100 0.100 1.000 0.001 -- 20* 97.299 0.500 0.100 0.100 2.000 0.001 --21 99.100 0.500 0.100 0.100 0.100 0.100 --22 98.200 0.500 0.100 0.100 0.100 1.000 -- 23* 97.200 0.500 0.100 0.100 0.100 2.000 --24 98.899 0.500 0.100 0.100 0.100 0.300 B.sub.2 O.sub.3 0.00125 98.899 0.500 0.100 0.100 0.100 0.300 NiO 0.00126 98.800 0.500 0.100 0.100 0.100 0.300 MoO.sub.3 0.10027 98.800 0.500 0.100 0.100 0.100 0.300 Fe.sub.2 O.sub.3 0.10028 97.900 0.500 0.100 0.100 0.100 0.300 Al.sub.2 O.sub.3 1.00029 97.900 0.500 0.100 0.100 0.100 0.300 Li.sub.2 O.sub.3 1.00030 96.900 0.500 0.100 0.100 0.100 0.300 CaO 2.00031 96.900 0.500 0.100 0.100 0.100 0.300 TiO.sub.2 2.000 32* 94.900 0.500 0.100 0.100 0.100 0.300 B.sub.2 O.sub.3 4.00033 98.790 0.500 0.100 0.100 0.100 0.300 B.sub.2 O.sub.3 0.010 Fe.sub.2 O.sub. 3 0.10034 98.645 0.500 0.100 0.100 0.100 0.300 Al.sub.2 O.sub.3 0.100 Li.sub.2 O 0.005 CaO 0.100 TiO.sub.2 0.05035 98.500 0.500 0.100 0.100 0.100 0.300 Cr.sub.2 O.sub.3 0.100 BeO 0.30036 98.590 0.500 0.100 0.100 0.100 0.300 MoO.sub.3 0.300 P.sub.2 O.sub.5 0.01037 98.650 0.500 0.100 0.100 0.100 0.300 Li.sub.2 O 0.050 Al.sub.2 O.sub.3 0.200 38* 96.400 0.500 0.100 0.100 0.100 0.300 NiO 0.500 Fe.sub.2 O.sub.3 1.000 CaO 1.000__________________________________________________________________________ Marked * are comparison examples which are outside the claimed scope.
TABLE 8______________________________________SampleNo. V1mA/mm (V) .alpha. .epsilon. tan .delta. (%)______________________________________ 1* 83.0 1.3 1.0 .times. 10.sup.5 94.0 2* 50.6 6.0 1.9 .times. 10.sup.4 7.4 3* 35.2 6.2 3.1 .times. 10.sup.4 6.0 4* 39.7 6.5 4.0 .times. 10.sup.4 5.4 5 50.1 7.7 5.0 .times. 10.sup.4 3.0 6 48.7 7.6 5.2 .times. 10.sup.4 2.9 7 45.9 7.8 5.4 .times. 10.sup.4 2.8 8 60.0 8.0 5.3 .times. 10.sup.4 3.0 9 75.5 8.5 4.2 .times. 10.sup.4 2.9 10* 195.0 10.7 1.1 .times. 10.sup.3 2.911 54.0 8.1 4.9 .times. 10.sup.4 3.112 47.2 8.0 5.0 .times. 10.sup.4 3.013 44.5 8.0 5.7 .times. 10.sup.4 3.2 14* 56.2 4.7 7.0 .times. 10.sup.4 14.715 53.4 7.6 3.9 .times. 10.sup.4 2.916 88.7 8.4 3.8 .times. 10.sup.4 2.7 17* 203.1 10.5 1.6 .times. 10.sup.3 1.118 60.5 8.3 4.0 .times. 10.sup.4 3.319 89.7 11.0 3.1 .times. 10.sup.4 3.0 20* 601.2 13.2 1.0 .times. 10.sup.3 0.921 52.7 7.6 5.9 .times. 10.sup.4 2.722 84.7 9.2 4.3 .times. 10.sup.4 2.6 23* 89.5 5.1 2.9 .times. 10.sup.4 12.724 55.0 9.4 3.8 .times. 10.sup.4 2.825 47.2 9.3 4.9 .times. 10.sup.4 2.626 50.3 9.5 5.0 .times. 10.sup.4 2.727 71.5 9.5 5.0 .times. 10.sup.4 2.628 85.4 10.2 4.1 .times. 10.sup.4 2.829 79.0 10.2 4.0 .times. 10.sup.4 2.830 98.1 10.2 4.1 .times. 10.sup.4 2.931 90.4 10.3 1.0 .times. 10.sup.4 2.7 32* 207.6 3.8 1.0 .times. 10.sup.3 7.933 59.7 9.1 4.0 .times. 10.sup.4 2.934 75.2 9.3 4.1 .times. 10.sup.4 2.635 77.1 10.1 4.2 .times. 10.sup.4 2.536 40.5 9.2 4.5 .times. 10.sup.4 3.137 63.3 9.8 3.9 .times. 10.sup.4 3.0 38* 259.0 10.4 1.1 .times. 10.sup.3 1.1______________________________________ Marked * are comparison examples which are outside the claimed scope.
<EXAMPLE 5>
After measuring SrCO.sub.3 and TiO.sub.2 in a manner that SrTiO.sub.3 having Sr/Ti atom ratio of 0.98 is obtained, and they are blended and ground for 12 hours in wet method in a ball-mill or the like and dried. Then, the mixture is again ground, and thereafter, the ground powder is press-formed into a disk of a size of 80 mm diameter and 50 mm thickness by a pressing force of 1.0 ton/cm.sup.2. The press-formed body then is calcined at 1200.degree. C. for 4 hours, and further ground by a ball-mill or the like for about 20 hours, thereby to preparee a host material powder of SrTiO.sub.3.
Next, SrTiO.sub.3, Y.sub.2 O.sub.3, Co.sub.2 O.sub.3, CuO, Ag.sub.2 O and BaO, and further, one of B.sub.2 O.sub.3, NiO, MoO.sub.3, BeO, Fe.sub.2 O.sub.3, Al.sub.2 O.sub.3, Li.sub.2 O, Cr.sub.2 O.sub.3, PbO, CaO, TiO.sub.2, P.sub.2 O.sub.5, Sb.sub.2 O.sub.3 and V.sub.2 O.sub.5 are measured in a composition ratio shown in Table 9, and press-formed and fired in the same manner as EXAMPLE 1. And the resultant element was measured in the similar conditions as those of EXAMPLE 1, and the results are shown in Table 10.
TABLE 9______________________________________Sam-ple Composition ratio (mol %)No. SrTiO.sub.3 Y.sub.2 O.sub.3 Co.sub.2 O.sub.3 CuO Ag.sub.2 O BaO Additive______________________________________ 1* 99.999 0.001 -- -- -- -- -- 2* 99.998 0.001 0.001 -- -- -- -- 3* 99.997 0.001 0.001 0.001 -- -- -- 4* 99.996 0.001 0.001 0.001 0.001 -- --5 99.995 0.001 0.001 0.001 0.001 0.001 --6 99.986 0.010 0.001 0.001 0.001 0.001 --7 99.896 0.100 0.001 0.001 0.001 0.001 --8 98.996 1.000 0.001 0.001 0.001 0.001 --9 97.996 2.000 0.001 0.001 0.001 0.001 -- 10* 95.996 4.000 0.001 0.001 0.001 0.001 --11 99.397 0.500 0.100 0.001 0.001 0.001 --12 98.497 0.500 1.000 0.001 0.001 0.001 --13 97.497 0.500 2.000 0.001 0.001 0.001 -- 14* 95.497 0.500 4.000 0.001 0.001 0.001 --15 99.298 0.500 0.100 0.100 0.001 0.001 --16 98.398 0.500 0.100 1.000 0.001 0.001 -- 17* 97.398 0.500 0.100 2.000 0.001 0.001 --18 99.199 0.500 0.100 0.100 0.100 0.001 --19 98.299 0.500 0.100 0.100 1.000 0.001 -- 20* 97.299 0.500 0.100 0.100 2.000 0.001 --21 99.100 0.500 0.100 0.100 0.100 0.100 --22 98.200 0.500 0.100 0.100 0.100 1.000 -- 23* 97.200 0.500 0.100 0.100 0.100 2.000 --24 98.899 0.500 0.100 0.100 0.100 0.300 B.sub.2 O.sub.3 0.00125 98.899 0.500 0.100 0.100 0.100 0.300 NiO 0.00126 98.800 0.500 0.100 0.100 0.100 0.300 MoO.sub.3 0.00127 98.800 0.500 0.100 0.100 0.100 0.300 Fe.sub.2 O.sub.3 0.10028 97.900 0.500 0.100 0.100 0.100 0.300 Al.sub.2 O.sub.3 1.00029 97.900 0.500 0.100 0.100 0.100 0.300 Li.sub.2 O 1.00030 96.900 0.500 0.100 0.100 0.100 0.300 CaO 2.00031 96.900 0.500 0.100 0.100 0.100 0.300 TiO.sub.2 2.000 32* 94.900 0.500 0.100 0.100 0.100 0.300 B.sub.2 O.sub.3 4.00033 98.790 0.500 0.100 0.100 0.100 0.300 B.sub.2 O.sub.3 0.010 Fe.sub. 2 O.sub.3 0.10034 98.645 0.500 0.100 0.100 0.100 0.300 Al.sub.2 O.sub.3 0.100 Li.sub.2 O 0.005 CaO 0.100 TiO.sub.2 0.05035 98.500 0.500 0.100 0.100 0.100 0.300 Fe.sub.2 O.sub.3 0.100 V.sub.2 O.sub.5 0.30036 98.590 0.500 0.100 0.100 0.100 0.300 BeO 0.300 P.sub.2 O.sub.5 0.01037 98.650 0.500 0.100 0.100 0.100 0.300 Cr.sub.2 O.sub.3 0.050 TiO.sub.2 0.200 38* 96.400 0.500 0.100 0.100 0.100 0.300 MoO.sub.3 0.500 Sb.sub.2 O.sub.3 1.000 Al.sub.2 O.sub.3 1.000______________________________________ Marked * are comparison examples which are outside the claimed scope.
TABLE 10______________________________________SampleNo. V.sub.1 mA/mm (V) .alpha. .epsilon. tan .delta. (%)______________________________________ 1* 83.0 1.3 1.0 .times. 10.sup.6 94.0 2* 50.6 6.0 1.9 .times. 10.sup.4 7.4 3* 35.2 6.2 3.1 .times. 10.sup.4 6.0 4* 39.7 6.5 4.0 .times. 10.sup.4 5.4 5 40.0 7.2 6.5 .times. 10.sup.4 3.1 6 37.8 7.1 6.6 .times. 10.sup.4 3.0 7 39.5 7.3 6.9 .times. 10.sup.4 3.0 8 51.1 7.6 6.7 .times. 10.sup.4 3.0 9 60.7 8.4 5.8 .times. 10.sup.4 3.0 10* 158.9 10.1 1.2 .times. 10.sup.3 3.011 44.2 7.9 5.8 .times. 10.sup.4 3.112 39.3 7.9 6.4 .times. 10.sup.4 3.113 35.6 8.0 7.3 .times. 10.sup.4 3.1 14* 45.3 4.1 8.4 .times. 10.sup.4 16.215 45.4 7.3 5.3 .times. 10.sup.4 2.916 78.1 8.1 5.1 .times. 10.sup.4 2.8 17* 185.3 10.2 1.3 .times. 10.sup.3 1.518 50.9 8.0 5.5 .times. 10.sup.4 3.519 77.9 10.6 4.9 .times. 10.sup.4 3.0 20* 420.2 11.9 1.1 .times. 10.sup.3 1.021 40.5 7.2 6.4 .times. 10.sup.4 2.922 75.3 8.9 5.7 .times. 10.sup.4 2.9 23* 80.9 4.6 3.0 .times. 10.sup.4 16.424 47.5 9.2 4.5 .times. 10.sup.4 3.025 39.3 9.3 4.9 .times. 10.sup.4 2.926 40.4 9.3 5.8 .times. 10.sup.4 2.927 65.2 9.3 6.1 .times. 10.sup.4 2.828 74.9 10.0 5.7 .times. 10.sup.4 2.829 69.8 10.1 5.5 .times. 10.sup.4 2.930 89.4 10.2 5.5 .times. 10.sup.4 2.831 80.8 10.3 1.4 .times. 10.sup.4 2.8 32* 157.6 3.7 1.0 .times. 10.sup.3 9.133 42.0 9.0 5.2 .times. 10.sup.4 3.034 69.2 9.1 5.3 .times. 10.sup.4 2.935 69.9 9.8 5.7 .times. 10.sup.4 2.436 35.3 9.0 5.1 .times. 10.sup.4 3.137 57.8 9.4 4.3 .times. 10.sup.4 3.1 38* 191.6 10.1 1.0 .times. 10.sup.3 1.7______________________________________ Marked * are comparison examples which are outside the claimed scope.
<EXAMPLE 6>
After measuring SrCO.sub.3 and TiO.sub.2 in a manner that SrTiO.sub.3 having Sr/Ti atom ratio of 0.98 is obtained, and they are blended and ground for 12 hours in wet method in a ball-mill or the like and dried. Then, the mixture is again ground, and thereafter, the ground powder is press-formed into a disk of a size of 80 mm diameter and 50 mm thickness by a pressing force of 1.0 ton/cm.sup.2. The press-formed body than is calcinated at 1200.degree. C. for 4 hours, and further ground by a ball-mill or the like for about 20 hours, thereby to prepare a host material powder of SrTiO.sub.3.
Next, SrTiO.sub.3, Y.sub.2 O.sub.3, Co.sub.2 O.sub.3, CuO, Ag.sub.2 O and SiO.sub.2, and further, one of B.sub.2 O.sub.3, MnO.sub.2, NiO, MoO.sub.3, BeO, Fe.sub.2 O.sub.3, Al.sub.2 O.sub.3, Li.sub.2 O, Cr.sub.2 O.sub.3, ZrO.sub.2, PbO, BaO, CaO, MgO, TiO.sub.2, ZnO, P.sub.2 O.sub.5, Sb.sub.2 O.sub.3 and v.sub.2 O.sub.5 are measured in a composition ratio shown in Table 11, and press-formed and fired in the same manner as EXAMPLE 1. And the resultant element was measured in the similar conditions as those of EXAMPLE 1, and the results are shown in Table 12.
TABLE 11______________________________________Sam-ple Composition ratio (mol %)No. SrTiO.sub.3 Y.sub.2 O.sub.3 Co.sub.2 O.sub.3 CuO Ag.sub.2 O SiO.sub.2 Additive______________________________________ 1* 99.999 0.001 -- -- -- -- -- 2* 99.998 0.001 0.001 -- -- -- -- 3* 99.997 0.001 0.001 0.001 -- -- -- 4* 99.996 0.001 0.001 0.001 0.001 -- -- 5 99.995 0.001 0.001 0.001 0.001 0.001 -- 6 99.986 0.010 0.001 0.001 0.001 0.001 -- 7 99.896 0.100 0.001 0.001 0.001 0.001 -- 8 98.996 1.000 0.001 0.001 0.001 0.001 -- 9 97.996 2.000 0.001 0.001 0.001 0.001 -- 10* 95.996 4.000 0.001 0.001 0.001 0.001 --11 99.397 0.500 0.100 0.001 0.001 0.001 --12 98.497 0.500 1.000 0.001 0.001 0.001 --13 97.497 0.500 2.000 0.001 0.001 0.001 -- 14* 95.497 0.500 4.000 0.001 0.001 0.001 --15 99.298 0.500 0.100 0.100 0.001 0.001 --16 98.398 0.500 0.100 1.000 0.001 0.001 -- 17* 97.398 0.500 0.100 2.000 0.001 0.001 --18 99.199 0.500 0.100 0.100 0.100 0.001 --19 98.299 0.500 0.100 0.100 1.000 0.001 -- 20* 97.299 0.500 0.100 0.100 2.000 0.001 --21 99.100 0.500 0.100 0.100 0.100 0.100 --22 98.200 0.500 0.100 0.100 0.100 1.000 -- 23* 97.200 0.500 0.100 0.100 0.100 2.000 --24 98.899 0.500 0.100 0.100 0.100 0.300 B.sub.2 O.sub.3 0.00125 98.899 0.500 0.100 0.100 0.100 0.300 NiO 0.00126 98.800 0.500 0.100 0.100 0.100 0.300 MoO.sub.3 0.10027 98.800 0.500 0.100 0.100 0.100 0.300 Fe.sub.2 O.sub.3 0.10028 97.900 0.500 0.100 0.100 0.100 0.300 Al.sub.2 O.sub.3 1.00029 97.900 0.500 0.100 0.100 0.100 0.300 Li.sub.2 O 1.00030 96.900 0.500 0.100 0.100 0.100 0.300 CaO 2.00031 96.900 0.500 0.100 0.100 0.100 0.300 TiO.sub.2 2.000 32* 94.900 0.500 0.100 0.100 0.100 0.300 B.sub.2 O.sub.3 4.00033 98.790 0.500 0.100 0.100 0.100 0.300 B.sub.2 O.sub.3 0.010 Fe.sub.2 O.sub.3 0.10034 98.645 0.500 0.100 0.100 0.100 0.300 Al.sub.2 O.sub.3 0.100 Li.sub.2 O 0.005 CaO 0.100 TiO.sub.2 0.05035 98.500 0.500 0.100 0.100 0.100 0.300 MnO.sub.2 0.100 Al.sub.2 O.sub.3 0.30036 98.887 0.500 0.100 0.100 0.100 0.300 BaO 0.010 Li.sub.2 O 0.00337 98.500 0.500 0.100 0.100 0.100 0.300 Al.sub.2 O.sub.3 0.100 MgO 0.30038 98.400 0.500 0.100 0.100 0.100 0.300 TiO.sub.2 0.050 ZrO.sub.2 0.150 MnO.sub.2 0.300 39* 96.390 0.500 0.100 0.100 0.100 0.300 MgO 1.500 MnO.sub.2 1.000 TiO.sub.2 0.010______________________________________ Marked * are comparison examples which are outside the claimed scope.
TABLE 12______________________________________SampleNo. V.sub.1 mA/mm (V) .alpha. .epsilon. tan .delta. (%)______________________________________ 1* 83.0 1.3 1.0 .times. 10.sup.6 91.0 2* 50.6 6.0 1.9 .times. 10.sup.4 7.4 3* 35.2 6.2 3.1 .times. 10.sup.4 6.0 4* 39.7 6.5 4.0 .times. 10.sup.4 5.4 5 43.2 7.8 6.2 .times. 10.sup.4 3.1 6 41.9 7.6 6.3 .times. 10.sup.4 3.3 7 40.0 7.7 6.5 .times. 10.sup.4 3.3 8 52.4 7.9 5.7 .times. 10.sup.4 3.1 9 70.1 8.8 5.3 .times. 10.sup.4 2.7 10* 155.0 9.7 2.0 .times. 10.sup.3 2.211 40.9 7.8 5.3 .times. 10.sup.4 3.212 37.3 7.7 5.5 .times. 10.sup.4 3.713 38.7 7.1 6.1 .times. 10.sup.4 4.3 14* 45.1 5.7 8.0 .times. 10.sup.4 28.915 47.2 7.2 4.3 .times. 10.sup.4 3.116 89.0 8.9 4.1 .times. 10.sup.4 2.4 17* 304.9 11.4 1.9 .times. 10.sup.3 1.018 52.3 8.0 4.5 .times. 10.sup.4 2.819 94.0 10.9 4.1 .times. 10.sup.4 2.3 20* 909.4 15.3 1.1 .times. 10.sup.3 0.921 49.7 8.0 6.3 .times. 10.sup.4 3.022 80.5 9.4 5.1 .times. 10.sup.4 2.7 23* 84.9 6.9 2.8 .times. 10.sup.4 11.524 51.3 9.7 3.9 .times. 10.sup.4 3.225 40.9 9.2 5.3 .times. 10.sup.4 3.526 43.4 9.5 5.5 .times. 10.sup.4 3.427 62.1 9.5 4.7 .times. 10.sup.4 2.728 75.5 10.1 4.2 .times. 10.sup.4 2.429 74.0 10.0 4.3 .times. 10.sup.4 2.130 97.1 10.3 3.8 .times. 10.sup.4 2.231 88.8 10.5 3.5 .times. 10.sup.4 2.3 32* 210.4 4.1 1.7 .times. 10.sup.3 3.933 55.1 9.1 4.3 .times. 10.sup.4 2.234 70.8 9.7 5.0 .times. 10.sup.4 2.035 75.0 10.9 4.9 .times. 10.sup.4 2.036 54.0 9.2 5.7 .times. 10.sup.4 2.937 64.3 9.5 5.5 .times. 10.sup.4 2.738 102.5 10.8 3.9 .times. 10.sup.4 1.5 39* 899.0 16.5 1.0 .times. 10.sup.3 0.8______________________________________ Marked * are comparison examples which are outside the claimed scope.
<EXAMPLE 7>
After measuring SrCO.sub.3 and TiO.sub.2 in a manner that SrTiO.sub.3 having Sr/Ti atom ratio of 0.98 is obtained, and they are blended and ground for 12 hours in wet method in a ball-mill or the like and dried. Then, the mixture is again ground, and thereafter, the ground powder is press-formed into a disk of a size of 80 mm diameter and 50 mm thickness by a pressing force of 1.0 ton/cm.sup.2. The press-formed body then is calcinated at 1200.degree. C. for 4 hours, and further ground by a ball-mill or the like for about 20 hours, thereby to prepare a host material powder of SrTiO.sub.3.
Next, SrTiO.sub.3, Y.sub.2 O.sub.3, Co.sub.2 O.sub.3, CuO, Ag.sub.2 O and SiO.sub.2, and further, one of B.sub.2 O.sub.3, MnO.sub.2, NiO, MoO.sub.3, BeO, Fe.sub.2 O.sub.3, Al.sub.2 O.sub.3, Li.sub.2 O, Cr.sub.2 O.sub.3, ZrO.sub.2, PbO, BaO, CaO, MgO, TiO.sub.2, ZnO, P.sub.2 O.sub.5, Sb.sub.2 O.sub.3 and V.sub.2 O.sub.5 are measured in a composition ratio shown in Table 13, and press-formed and fired in the same manner as EXAMPLE 1. And the resultant element was measured in the similar conditions as those of EXAMPLE 1, and the results are shown in Table 14.
TABLE 13______________________________________Sam-ple Comparison ratio (mol %)No. SrTiO.sub.3 Y.sub.2 O.sub.3 Co.sub.2 O.sub.3 CuO Ag.sub.2 O MgO Additive______________________________________ 1* 99.999 0.001 -- -- -- -- -- 2* 99.998 0.001 0.001 -- -- -- -- 3* 99.997 0.001 0.001 0.001 -- -- -- 4* 99.996 0.001 0.001 0.001 0.001 -- -- 5 99.995 0.001 0.001 0.001 0.001 0.001 -- 6 99.986 0.010 0.001 0.001 0.001 0.001 -- 7 99.896 0.100 0.001 0.001 0.001 0.001 -- 8 98.996 1.000 0.001 0.001 0.001 0.001 -- 9 97.996 2.000 0.001 0.001 0.001 0.001 -- 10* 95.996 4.000 0.001 0.001 0.001 0.001 --11 99.397 0.500 0.100 0.001 0.001 0.001 --12 98.497 0.500 1.000 0.001 0.001 0.001 --13 97.497 0.500 2.000 0.001 0.001 0.001 -- 14* 95.497 0.500 4.000 0.001 0.001 0.001 --15 99.298 0.500 0.100 0.100 0.001 0.001 --16 98.398 0.500 0.100 1.000 0.001 0.001 -- 17* 97.398 0.500 0.100 2.000 0.001 0.001 --18 99.199 0.500 0.100 0.100 0.100 0.001 --19 98.299 0.500 0.100 0.100 1.000 0.001 -- 20* 97.299 0.500 0.100 0.100 2.000 0.001 --21 99.100 0.500 0.100 0.100 0.100 0.100 --22 98.200 0.500 0.100 0.100 0.100 1.000 -- 23* 97.200 0.500 0.100 0.100 0.100 2.000 --24 98.899 0.500 0.100 0.100 0.100 0.300 B.sub.2 O.sub.3 0.00125 98.899 0.500 0.100 0.100 0.100 0.300 NiO 0.00126 98.800 0.500 0.100 0.100 0.100 0.300 MoO.sub.3 0.10027 98.800 0.500 0.100 0.100 0.100 0.300 Fe.sub.2 O.sub.3 0.10028 97.900 0.500 0.100 0.100 0.100 0.300 Al.sub.2 O.sub.3 1.00029 97.900 0.500 0.100 0.100 0.100 0.300 Li.sub.2 O 1.00030 96.900 0.500 0.100 0.100 0.100 0.300 CaO 2.00031 96.900 0.500 0.100 0.100 0.100 0.300 TiO.sub.2 2.000 32* 94.900 0.500 0.100 0.100 0.100 0.300 B.sub.2 O.sub.3 4.00033 98.790 0.500 0.100 0.100 0.100 0.300 B.sub.2 O.sub.3 0.010 Fe.sub.2 O.sub.3 0.10034 98.645 0.500 0.100 0.100 0.100 0.300 Al.sub.2 O.sub.3 0.100 Li.sub.2 O 0.005 CaO 0.100 TiO.sub.2 0.05035 98.300 0.500 0.100 0.100 0.100 0.300 V.sub.2 O.sub.5 0.100 CaO 0.50036 98.350 0.500 0.100 0.100 0.100 0.300 Sb.sub.2 O.sub.3 0.050 TiO.sub.2 0.50037 98.100 0.500 0.100 0.100 0.100 0.300 NiO 0.300 Al.sub.2 O.sub.3 0.500 38* 96.795 0.500 0.100 0.100 0.100 0.300 BeO 0.005 Cr.sub.2 O.sub.3 1.100 CaO 1.000______________________________________ Marked * are comparison examples which are outside the claimed scope.
TABLE 14______________________________________SampleNo. V.sub.1 mA/mm (V) .alpha. .epsilon. tan.delta. (%)______________________________________ 1* 83.0 1.3 1.0 .times. 10.sup.6 94.0 2* 50.6 6.0 1.9 .times. 10.sup.4 7.4 3* 35.2 6.2 3.1 .times. 10.sup.4 6.0 4* 39.7 6.5 4.0 .times. 10.sup.4 5.4 5 48.1 7.5 4.9 .times. 10.sup.4 2.9 6 46.5 7.7 5.1 .times. 10.sup.4 2.8 7 43.8 7.8 5.2 .times. 10.sup.4 2.7 8 55.7 8.1 5.3 .times. 10.sup.4 2.9 9 73.6 8.4 4.3 .times. 10.sup.4 2.8 10* 181.0 9.8 1.0 .times. 10.sup.3 2.811 51.5 8.2 4.8 .times. 10.sup.4 2.812 45.3 8.2 5.1 .times. 10.sup.4 2.813 41.6 8.1 5.6 .times. 10.sup.4 2.9 14* 55.0 4.4 6.1 .times. 10.sup.4 11.515 52.2 7.7 4.2 .times. 10.sup.4 2.716 87.8 8.3 4.1 .times. 10.sup.4 2.5 17* 180.5 10.2 1.3 .times. 10.sup.3 0.718 58.3 8.1 4.2 .times. 10.sup.4 2.919 87.7 10.7 3.9 .times. 10.sup.4 2.9 20* 349.1 12.9 1.1 .times. 10.sup.3 0.921 50.5 7.2 5.7 .times. 10.sup.4 2.522 82.2 9.0 4.1 .times. 10.sup.4 2.4 23* 85.8 5.2 1.9 .times. 10.sup.4 11.924 54.1 9.2 3.9 .times. 10.sup.4 1.825 42.3 9.3 4.7 .times. 10.sup.4 1.426 47.8 9.4 4.9 .times. 10.sup.4 1.727 65.6 9.5 5.0 .times. 10.sup.4 1.828 80.5 10.0 4.2 .times. 10.sup.4 1.529 66.3 10.0 4.1 .times. 10.sup.4 1.730 93.4 10.1 4.1 .times. 10.sup.4 1.431 84.4 10.0 1.0 .times. 10.sup.4 1.4 32* 172.3 2.4 1.0 .times. 10.sup.3 9.533 57.2 9.0 4.1 .times. 10.sup.4 2.034 81.8 9.2 4.1 .times. 10.sup.4 1.735 55.3 10.2 4.4 .times. 10.sup.4 1.836 70.4 10.3 4.7 .times. 10.sup.4 1.437 78.5 10.5 4.3 .times. 10.sup.4 1.4 38* 241.9 11.7 1.1 .times. 10.sup.3 0.9______________________________________ Marked * are comparison examples which are outside the claimed scope.
<EXAMPLE 8>
After measuring SrCO.sub.3 and TiO.sub.2 in a manner that SrTiO.sub.3 having Sr/Ti atom ratio of 0.98 is obtained, and they are blended and ground for 12 hours in wet method in a ball-mill or the like and dried. Then, the mixture is again ground, and thereafter, the ground powder is press-formed into a disk of a size of 80 mm diameter and 50 mm thickness by a pressing force of 1.0 ton/cm.sup.2. The press-formed body then is calcinated at 1200.degree. C. for 4 hours, and further ground by a ball-mill or the like for about 20 hours, thereby to prepare a host material powder of SrTiO.sub.3.
Next, SrTiO.sub.3, Y.sub.2 O.sub.3, Co.sub.2 O.sub.3, CuO, Ag.sub.2 O and MnO.sub.2, and further, one of B.sub.2 O.sub.3, NiO, MoO.sub.3, BeO, Fe.sub.2 O.sub.3, Al.sub.2 O.sub.3, Li.sub.2 O, Cr.sub.2 O.sub.3, PbO, CaO, TiO.sub.2, P.sub.2 O.sub.5, Sb.sub.2 O.sub.3 and V.sub.2 O.sub.5 are measured in a composition ratio shown in Table 15, and press-formed and fired in the same manner as EXAMPLE 1. And the resultant element was measured in the similar conditions as those of EXAMPLE 1, and the results are shown in Table 16.
TABLE 15______________________________________Sam-ple Composition ratioNo. SrTiO.sub.3 Y.sub.2 O.sub.3 Co.sub.2 O.sub.3 CuO Ag.sub.2 O MnO.sub.2 Additive______________________________________ 1* 99.999 0.001 -- -- -- -- -- 2* 99.998 0.001 0.001 -- -- -- -- 3* 99.997 0.001 0.001 0.001 -- -- -- 4* 99.996 0.001 0.001 0.001 0.001 -- -- 5 99.995 0.001 0.001 0.001 0.001 0.001 -- 6 99.986 0.010 0.001 0.001 0.001 0.001 -- 7 99.896 0.100 0.001 0.001 0.001 0.001 -- 8 98.996 1.000 0.001 0.001 0.001 0.001 -- 9 97.996 2.000 0.001 0.001 0.001 0.001 -- 10* 95.996 4.000 0.001 0.001 0.001 0.001 --11 99.397 0.500 0.100 0.001 0.001 0.001 --12 98.497 0.500 1.000 0.001 0.001 0.001 --13 97.497 0.500 2.000 0.001 0.001 0.001 -- 14* 95.497 0.500 4.000 0.001 0.001 0.001 --15 99.298 0.500 0.100 0.100 0.001 0.001 --16 98.398 0.500 0.100 1.000 0.001 0.001 -- 17* 97.398 0.500 0.100 2.000 0.001 0.001 --18 99.199 0.500 0.100 0.100 0.100 0.001 --19 98.299 0.500 0.100 0.100 1.000 0.001 -- 20* 97.299 0.500 0.100 0.100 2.000 0.001 --21 99.100 0.500 0.100 0.100 0.100 0.100 --22 98.200 0.500 0.100 0.100 0.100 1.000 -- 23* 97.200 0.500 0.100 0.100 0.100 2.000 --24 98.899 0.500 0.100 0.100 0.100 0.300 B.sub.2 O.sub.3 0.00125 98.899 0.500 0.100 0.100 0.100 0.300 NiO 0.00126 98.800 0.500 0.100 0.100 0.100 0.300 MoO.sub.3 0.10027 98.800 0.500 0.100 0.100 0.100 0.300 Fe.sub.2 O.sub.3 0.10028 97.900 0.500 0.100 0.100 0.100 0.300 Al.sub.2 O.sub.3 1.00029 97.900 0.500 0.100 0.100 0.100 0.300 Li.sub.2 O 1.00030 96.900 0.500 0.100 0.100 0.100 0.300 CaO 2.00031 96.900 0.500 0.100 0.100 0.100 0.300 TiO.sub.2 2.000 32* 94.900 0.500 0.100 0.100 0.100 0.300 B.sub.2 O.sub.3 4.00033 98.790 0.500 0.100 0.100 0.100 0.300 B.sub.2 O.sub. 3 0.100 Fe.sub.2 O.sub.3 0.10034 98.645 0.500 0.100 0.100 0.100 0.300 Al.sub.2 O.sub.3 0.100 Li.sub.2 O 0.005 CaO 0.100 TiO.sub.2 0.05035 98.500 0.500 0.100 0.100 0.100 0.300 MoO.sub.3 0.100 CaO 0.30036 98.887 0.500 0.100 0.100 0.100 0.300 PbO 0.010 Al.sub.2 O.sub.3 0.30037 98.445 0.500 0.100 0.100 0.100 0.300 Fe.sub.2 O.sub.3 0.005 Cr.sub.2 O.sub.3 0.150 TiO.sub.2 0.300 38* 96.300 0.500 0.100 0.100 0.100 0.300 BeO 0.100 Li.sub.2 O 1.000 CaO 1.500______________________________________ Marked * are comparison examples which are outside the claimed scope.
TABLE 16______________________________________SampleNo. V.sub.1 mA/mm (V) .alpha. .epsilon. tan .delta. (%)______________________________________ 1* 83.0 1.3 1.0 .times. 10.sup.6 94.0 2* 50.6 6.0 1.9 .times. 10.sup.4 7.4 3* 35.2 6.2 3.1 .times. 10.sup.4 6.0 4* 39.7 6.5 4.0 .times. 10.sup.4 5.4 5 55.3 8.0 6.0 .times. 10.sup.4 3.5 6 53.9 8.7 6.1 .times. 10.sup.4 3.4 7 50.5 8.9 6.4 .times. 10.sup.4 3.6 8 64.2 9.1 5.6 .times. 10.sup.4 3.3 9 80.5 9.9 4.8 .times. 10.sup.4 3.2 10* 209.4 10.5 1.5 .times. 10.sup.3 3.111 59.0 9.1 5.2 .times. 10.sup.4 3.412 48.7 8.9 5.3 .times. 10.sup.4 3.513 48.8 8.5 5.9 .times. 10.sup.4 4.4 14* 55.9 5.5 7.5 .times. 10.sup.4 30.415 58.2 7.4 4.5 .times. 10.sup.4 3.016 100.0 8.9 3.9 .times. 10.sup.4 2.8 17* 341.3 12.0 1.7 .times. 10.sup.3 0.918 63.4 8.5 4.0 .times. 10.sup.4 3.319 100.9 11.3 3.8 .times. 10.sup.4 2.9 20* 814.4 14.8 1.2 .times. 10.sup.3 0.821 57.9 8.1 6.1 .times. 10.sup.4 3.122 92.4 9.5 4.4 .times. 10.sup.4 3.0 23* 95.9 6.5 3.1 .times. 10.sup.4 15.224 63.2 9.8 4.3 .times. 10.sup.4 3.325 51.8 9.5 5.0 .times. 10.sup.4 3.426 54.6 9.7 5.1 .times. 10.sup.4 3.527 75.3 9.5 4.3 .times. 10.sup.4 3.128 89.5 9.3 4.0 .times. 10.sup.4 3.029 83.4 9.2 4.0 .times. 10.sup.4 2.930 108.9 9.3 4.5 .times. 10.sup.4 2.831 99.0 9.6 3.4 .times. 10.sup.4 2.8 32* 354.1 4.0 1.0 .times. 10.sup.3 4.433 63.8 9.2 3.9 .times. 10.sup.4 2.534 81.5 9.6 4.0 .times. 10.sup.4 2.435 60.5 9.9 5.2 .times. 10.sup.4 2.336 45.4 9.0 5.6 .times. 10.sup.4 3.237 95.7 10.4 3.8 .times. 10.sup.4 3.0 38* 385.2 15.1 1.0 .times. 10.sup.3 0.9______________________________________ Marked * are comparison examples which are outside the claimed scope.
As shown by the EXAMPLES 1-3, addition of Y.sub.2 O.sub.3 accelerates semiconductorization of SrTiO.sub.3, Sr.sub.1-x Ba.sub.x TiO.sub.3 and Sr.sub.1-x Ca.sub.x TiO.sub.3, and thereby can decrease specific resistance when the reducing firing is made and shows varistor characteristic when it is reoxidized in the air. However, when the additive is only Y.sub.2 O.sub.3, the .alpha. is small and the tan .delta. is large, and the element is not suitable for actual use.
Additions of Co.sub.2 O.sub.3 and CuO induce increase of .alpha. and decrease of tan .delta..
Additions of Ag.sub.2 O or Al.sub.2 O.sub.3 improves varistor characteristics, keeping the capacitor characteristics.
The reason of the above-mentioned changes of characteristics by the additions is that these additives segregate at grain boundaries, thereby selectively increasing the resistance of the grain boundaries. The grain boundaries of high resistance formed in this way functions as capacitors with very short gap between electrodes, as well as as varistor. Therefore, the resultant element becomes a varistor having a large capacity.
As the additives to make the grain boundary selectively to a high resistance to give the characteristics of a capacitor and a varistor at the same time, ZrO.sub.2, BaO, SiO.sub.2, MgO, MnO.sub.2, B.sub.2 O.sub.3, NiO, MoO.sub.3, BeO, Fe.sub.2 O.sub.3, Li.sub.2 O, Cr.sub.2 O.sub.3, PbO, CaO, TiO.sub.2, P.sub.2 O.sub.5, Sb.sub.2 O.sub.3 and V.sub.2 O.sub.5 are especially effective.
These additives make effect when added in an amount of over 0.001 mol %, but when the amount exceeds 3.000 mol % the characteristic becomes poor. The reason of the characteristic becoming poor is due to increase of thickness of grain boundaries, hence decrease of capacitance thereof, which induces increase of varistor voltage and deterioration of varistor characteristic.
The average diameter of the grain of the element is about 100 .mu.m, and the larger the diameter becomes the more effective in lowering varistor voltage.
Besides, the additives mentioned in the above-mentioned EXAMPLES, other additives, such as two or more kinds of oxides selected from the group consisting of ZrO.sub.2, BaO, SiO.sub.2, MgO, MnO.sub.2, B.sub.2 O.sub.3, NiO, MoO.sub.3, BeO, Fe.sub.2 O.sub.3, LiO.sub.2, Cr.sub.2 O.sub.3, PbO, CaO, TiO.sub.2, P.sub.2 O.sub.5, Sb.sub.2 O.sub.3 and V.sub.2 O.sub.5 can be used, and in such case the similar good effect is obtainable.
With respect to the ratio of Sr/Ti is regarded to be effective on the dielectric characteristic of the dielectric substance of grain boundary type. For instance, the relation between Sr/Ti ratio and specific resistance .rho. and tan .delta. of the completed element are as shown in FIG. 6 and FIG. 7. As can be understood from these graphs, when the ratio Sr/Ti differs from 1 the specific resistance .rho. decreases and the semiconductorization is accelerated. Accordingly, the dielectric constant .epsilon. increases. On the other hand, as the ratio Sr/Ti differs from 1, the value tan .delta. increases. Accordingly, in actual element, the Sr/Ti ratio within a range of 1.05-0.95 is desirable in view of the harmoney between the specific resistance .rho. and tan .delta..
On an element manufactured in the above-mentioned process, electrodes were provided by, for instance, conductive paint containing conductive material such as Ag or the like, to complete a capacitor-varistor complex element to serve as a noise filter shown in FIG. 4. When noise A shown in FIG. 5 was impressed on the complex element, the output B of FIG. 5 was obtained. As is obvious from comparison of the curve A with the curve B, noise is satisfactorily removed for all range of frequency by this complex element filter. This is in contradistinction to the conventional filter shown by the curve C when noise elimination is not satisfactorily for all range, especially in the low frequency range. This filter is advantageous in comprising very few component parts and having no internal connection and hence, compactness of the configuration and size. The filter in accordance with the present invention is suitable for noise suppressing circuit in various kinds of electric and electronic appliances which is necessary for a protection of semiconductor devices in such appliances, and is very useful in industrial application.

Number	Date	Country
59-64014	Mar 1984	JPX
59-111171	May 1984	JPX
59-111172	May 1984	JPX
59-171987	Aug 1984	JPX
59-171988	Aug 1984	JPX
59-171989	Aug 1984	JPX
59-171990	Aug 1984	JPX
59-171991	Aug 1984	JPX

Number	Name	Date
4438214	Masuyama et al.	Mar 1984
4545929	Masuyama et al.	Oct 1985
4547314	Masuyama et al.	Oct 1985

Number	Date	Country
0040391	Nov 1981	EPX
0070540	Jan 1983	EPX
0101824	Mar 1984	EPX
0068899	Jun 1978	JPX
0078414	May 1983	JPX
2080789	Feb 1982	GBX

Voltage-dependent non-linear resistance ceramic composition

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