JPH0249525B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a voltage nonlinear resistor (hereinafter referred to as a varistor) used for absorbing abnormally high voltage in an electric circuit.

Conventional technology As an oxide varistor whose main component is ZnO,
ZnO with Bi ₂ O ₃ , CoO, MnO, Sb ₂ O ₃ , NiO and
For example, a varistor made by adding SiO ₂ was developed in 1973.
It is known from Publication No. -11076. Also, ZnO
Varistors made by adding SrO and CoO
6754), varistors made by adding BaO and CoO to ZnO (Special Publication No. 6755), ZnO
Varistors made by adding BaO and MnO ₂ (Special Publication 1973
-6756) are also known.

Problems to be Solved by the Invention However, the former varistor using bismuth has the advantage of a very large nonlinearity index α, but the nonlinearity in the large current region (approximately 10 to 100A) is Furthermore, it has the disadvantage that the biristor voltage changes greatly due to surges. On the other hand, the latter three types of varistors have a non-linearity index α of about 10 to 20, and in order to make the non-linearity index α about 30, it is necessary to use a sintered body made by adding SrO or BaO to ZnO. It has the disadvantage of having to be coated with CoO or MnO ₂ and fired again. Therefore, an object of the present invention is to provide a varistor that has relatively excellent nonlinearity in a large current region and excellent surge resistance.

Means for Solving the Problems The varistor of the present invention for achieving the above object contains zinc (Zn), bismuth (Bi), cobalt (Co), manganese (Mn), magnesium (Mg),
Calcium (Ca), strontium (Sr), barium (Ba), nickel (Ni), silicon (Si), tin (Sn), titanium (Ti), germanium (Ge), antimony (Sb), boron (B), Chromium (Cr), ytterbium (Yb), erbium (Er), yztrium (Y), lanthanum (La), praseodymium (Pr),
Neodymium (Nd), aluminum (Al), and lithium (Li) are combined with their typical oxides such as zinc oxide (ZnO), bismuth oxide (Bi ₂ O ₃ ), cobalt oxide (CoO), and manganese oxide (MnO). ), magnesium oxide (MgO), calcium oxide (CaO), strontium oxide (SrO), barium oxide (BaO), nickel oxide (NiO), silicon oxide (SiO ₂ ), tin oxide (SnO ₂ ), titanium oxide (TiO ₂ ), germanium oxide (GeO ₂ ), antimony oxide (Sb ₂ O ₃ ), boron oxide (B ₂ O ₃ ), chromium oxide (Cr ₂ O ₃ ), itterbium oxide (Yb ₂ O ₃ ), erbium oxide ( _{Er2O3 )} ,
Yttrium oxide (Y ₂ O ₃ ), lanthanum oxide (La ₂ O ₃ ), praseodymium oxide (Pr ₂ O ₃ ), neodymium oxide (Nd ₂ O ₃ ), aluminum oxide (Al ₂ O ₃ ), lithium oxide (Li ₂ O), with the composition converted to ZnO
(First component) 81.9 to 99.775 mol%, Bi ₂ O ₃ (second component) 0.1 to 3 mol%, CoO, MnO, MgO, CaO,
SrO, BaO, NiO, _SiO2 , _SnO2 , _TiO2 , _GeO2 ,
0.1 to 10 mol% of one or more of Sb ₂ O ₃ , B ₂ O ₃ and Cr ₂ O ₃ (third component), Yb ₂ O ₃ , Er ₂ O ₃ , Y ₂ O ₃ ,
One or more of La ₂ O ₃ , Pr ₂ O ₃ and Nd ₂ O ₃ (fourth component) 0.01 to 3 mol%, Al ₂ O ₃ (fifth component) 0.01 to 1
The sintered body contains Li ₂ O ₃ (sixth component) in an amount of 0.005 to 1.1 mol % (however, the molar ratio of Li ₂ O/Al ₂ O ₃ is 0.5 to 1.1).

Effect According to the above invention, due to the synergistic effect of each component,
It is possible to provide a varistor that has excellent voltage nonlinearity in a large current region and excellent surge resistance.

Embodiments Next, embodiments of the present invention will be described with reference to the drawings. In order to manufacture the oxide varistor of the present invention, first, ZnO was 81.9 to 99.775 mol% and Bi ₂ O ₃ was
0.1-3 mol%, CoO, MnO, MgO, CaO,
SrO, BaO, NiO, _SiO2 , _SnO2 , _TiO2 , _GeO2 ,
0.1 to 10 mol% of one or more of Sb ₂ O ₃ , B ₂ O ₃ and Cr ₂ O ₃ , Yb ₂ O ₃ , Er ₂ O ₃ , Y ₂ O ₃ , La ₂ O ₃ , Pr ₂ O ₃ and Nd 0.01 to 3 mol% of one or more types of ₂ O ₃ , Al ₂ O ₃
is 0.01 to 1 mol%, Li ₂ O is 0.005 to 1.1 mol%, and the oxide raw materials are weighed so that the total of these is 100 mol%, and after thoroughly mixing with a ball mill etc., It was granulated using an organic binder such as polyvinyl alcohol. Note that it is also possible to use hydroxides, carbonates, etc. instead of oxides as starting materials. Also, _MgTiO3 ,
Binary metal oxides such as CaTiO ₃ , Zn ₂ SnO ₄ and MgLa ₂ O ₄ may be added. 600~ if there is a problem with variations in dimensions or properties after molding or firing.
After calcining in air at 1000°C for 1 to 3 hours, it may be ground into fine powder and then granulated. The granulated powder of various compositions obtained in this way is
Pressure molded at a pressure of 2.0 ton/cm ² and finished into a disc shape with a diameter of 15.0 mm and a thickness of 2.0 mm.Furthermore, this molded product was fired in air at 1000 to 1400°C for 1 to 3 hours,
Finally, Ag paste was applied to both sides of this sintered body and electrodes were formed by baking to complete oxide varistor elements with various compositions.

FIG. 1 is a cross-sectional view of an oxide varistor manufactured by the method described above. It is considered that the varistor action of this oxide varistor is caused by the conductive microcrystal 1 and the high resistance layer 2 surrounding it. Therefore, by changing the material composition and firing conditions, the varistor voltage and nonlinear index can be controlled. As mentioned above, the varistor action occurs inside the sintered body, so there are no particular limitations on the material or formation method of the electrode 3, and electrodes such as those made by vapor deposition of Ag, In, Al, Sn, etc., or electrodes made from Ni plating, etc. also obtains similar results.

Varistor voltage V ₁ of various varistors manufactured by the above method, voltage ratio R showing nonlinearity,
When the voltage change rate ΔV ₁ indicating surge resistance was measured, the results shown in FIGS. 2 to 29 were obtained. In addition, in FIGS. 2 to 29, V ₁ , R, and ΔV ₁ values of typical compositions are marked with dots, circles, and triangles. Each drawing also shows the characteristics of a varistor whose composition is outside the scope of the present invention for comparison. Further, the amount (mol %) of each component on the horizontal axis of FIGS. 2 to 28 is shown on a logarithmic scale. Further, the varistor voltage _V1 was determined by measuring the terminal voltage when 1.0 mA was applied to the varistor having the structure shown in FIG. Voltage ratio R representing non-linearity
was determined by measuring the varistor terminal voltages V ₁ and V _5A at varistor currents of 1.0 mA and 5 A, and calculating V _5A /V ₁ . Therefore, the smaller the voltage ratio R, the better the voltage nonlinearity, and the larger the nonlinearity index α. The voltage change rate △V ₁ is a waveform of 8 × 20 μs.
This was determined by passing a surge current of 125 A through the varistor twice, measuring the varistor voltage V ₁ in the opposite direction before and after passing this current, and calculating the amount of change. Therefore, the smaller the voltage change rate ΔV ₁ (absolute value), the better the surge resistance and the better the stability against load.

Next, FIGS. 2 to 29 will be explained in detail.

Figure 2 shows the varistor voltage of a varistor with the following composition.
V ₁ , voltage ratio R, and voltage change rate ΔV ₁ are shown.

ZnO 93.31-98.26 mol% Bi ₂ O ₃ 0.05-5 mol% CoO 1 mol% constant Yb ₂ O ₃ 0.5 mol% constant Al ₂ O ₃ 0.1 mol% constant Li ₂ O 0.09 mol% constant Total 100 mol% i.e. Figure 2 shows the amount (mol%) and total amount of Bi ₂ O ₃
V ₁ , R, and ΔV ₁ of various varistors in which the amount of ZnO was changed to 100 mol % are shown. In addition,
In FIGS. 2 to 29, the amount of ZnO is naturally determined once the mole % of the component on the horizontal axis in each diagram is determined.

Figure 3 shows the varistor voltage of a varistor with the following composition.
V ₁ , voltage ratio R, and voltage change rate ΔV ₁ are shown.

ZnO 93.31-98.26 mol% Bi ₂ O ₃ 0.05-5 mol% SiO ₂ 1 mol% constant Yb ₂ O ₃ 0.5 mol% constant Al ₂ O ₃ 0.1 mol% constant Li ₂ O 0.09 mol% constant Total 100 mol% i.e. , FIG. 3 shows the characteristics of the composition shown in FIG. 2 in which CoO is replaced with SiO ₂ from the same group.

Figure 4 shows the varistor voltage of a varistor with the following composition.
V ₁ , voltage ratio R, and voltage change rate ΔV ₁ are shown.

ZnO 93.31-98.26 mol% Bi ₂ O ₃ 0.05-5 mol% Sb ₂ O ₃ 1 mol% constant Yb ₂ O ₃ 0.5 mol% constant Al ₂ O ₃ 0.1 mol% constant Li ₂ O 0.09 mol% constant Total 100 mol % That is, FIG. 4 shows the characteristics when CoO in the composition shown in FIG. 2 is replaced with Sb ₂ O ₃ from the same group.

Figure 5 shows the varistor voltage of a varistor with the following composition.
V ₁ , voltage ratio R, and voltage change rate ΔV ₁ are shown.

ZnO 78.31-98.26 mol% CoO 0.05-20 mol% Bi ₂ O ₃ 1 mol% constant Yb ₂ O ₃ 0.5 mol% constant Al ₂ O ₃ 0.1 mol% constant Li ₂ O 0.09 mol% constant Total 100 mol% i.e. Figure 5 shows the amount of CoO (mol%) and total
V ₁ , R, and ΔV ₁ of various varistors in which the amount of ZnO was changed to 100 mol % are shown.

Figure 6 shows the varistor voltage of a varistor with the following composition.
V ₁ , voltage ratio R, and voltage change rate ΔV ₁ are shown.

ZnO 78.31-98.26 mol% MnO 0.05-20 mol% Bi ₂ O ₃ 1 mol% constant Yb ₂ O ₃ 0.5 mol% constant Al ₂ O ₃ 0.1 mol% constant Li ₂ O 0.09 mol% constant Total 100 mol% i.e. Figure 6 shows the amount of MnO (mol%) and total
V ₁ , R, and ΔV ₁ of various varistors in which the amount of ZnO was changed to 100 mol % are shown.

Figure 7 shows the varistor voltage of a varistor with the following composition.
V ₁ , voltage ratio R, and voltage change rate ΔV ₁ are shown.

ZnO 78.31-98.26 mol% MgO 0.05-20 mol% Bi ₂ O ₃ 1 mol% constant Yb ₂ O ₃ 0.5 mol% constant Al ₂ O ₃ 0.1 mol% constant Li ₂ O 0.09 mol% constant Total 100 mol% i.e. Figure 7 shows the amount of MgO (mol%) and total
V ₁ , R, and ΔV ₁ of various varistors in which the amount of ZnO was changed to 100 mol % are shown.

Figure 8 shows the varistor voltage of a varistor with the following composition.
V ₁ , voltage ratio R, and voltage change rate ΔV ₁ are shown.

ZnO 78.31-98.26 mol% CaO 0.05-20 mol% Bi ₂ O ₃ 1 mol% constant Yb ₂ O ₃ 0.5 mol% constant Al ₂ O ₃ 0.1 mol% constant Li ₂ O 0.09 mol% constant Total 100 mol% i.e. Figure 8 shows the amount of CaO (mol%) and total
V ₁ , R, and ΔV ₁ of various varistors in which the amount of ZnO was changed to 100 mol % are shown.

Figure 9 shows the varistor voltage of a varistor with the following composition.
V ₁ , voltage ratio R, and voltage change rate ΔV ₁ are shown.

ZnO 78.31-98.26 mol% SrO 0.05-20 mol% Bi ₂ O ₃ 1 mol% constant Yb ₂ O ₃ 0.5 mol% constant Al ₂ O ₃ 0.1 mol% constant Li ₂ O 0.09 mol% constant Total 100 mol% i.e. Figure 9 shows the amount of SrO (mol%) and total
V ₁ , R, and ΔV ₁ of various varistors in which the amount of ZnO was changed to 100 mol % are shown.

Figure 10 shows the varistor voltage of a varistor with the following composition.
V ₁ , voltage ratio R, and voltage change rate ΔV ₁ are shown.

ZnO 78.31-98.26 mol% BaO 0.05-20 mol% Bi ₂ O ₃ 1 mol% constant Yb ₂ O ₃ 0.5 mol% constant Al ₂ O ₃ 0.1 mol% constant Li ₂ O 0.09 mol% constant Total 100 mol% i.e. FIG. 10 shows V ₁ , R, and ΔV ₁ of various varistors in which the amount of BaO (mol %) and the amount of ZnO were varied so that the total amount was 100 mol %.

Figure 11 shows the varistor voltage of a varistor with the following composition.
V ₁ , voltage ratio R, and voltage change rate ΔV ₁ are shown.

ZnO 78.31-98.26 mol% NiO 0.05-20 mol% Bi ₂ O ₃ 1 mol% constant Yb ₂ O ₃ 0.5 mol% constant Al ₂ O ₃ 0.1 mol% constant Li ₂ O 0.09 mol% constant Total 100 mol% i.e. Figure 11 shows the amount of NiO (mol%) and total
V ₁ , R, and ΔV ₁ of various varistors in which the amount of ZnO was changed to 100 mol % are shown.

Figure 12 shows the varistor voltage of a varistor with the following composition.
V ₁ , voltage ratio R, and voltage change rate ΔV ₁ are shown.

ZnO 78.31-98.26 mol% SiO ₂ 0.05-20 mol% Bi ₂ O ₃ 1 mol% constant Yb ₂ O ₃ 0.5 mol% constant Al ₂ O ₃ 0.1 mol% constant Li ₂ O 0.09 mol% constant Total 100 mol% i.e. , FIG. 12 shows V ₁ , R, and ΔV ₁ of various varistors in which the amount of SiO ₂ (mol %) and the amount of ZnO were varied so that the total amount was 100 mol %.

Figure 13 shows the varistor voltage of a varistor with the following composition.
V ₁ , voltage ratio R, and voltage change rate ΔV ₁ are shown.

ZnO 78.31-98.26 mol% SnO ₂ 0.05-20 mol% Bi ₂ O ₃ 1 mol% constant Yb ₂ O ₃ 0.5 mol% constant Al ₂ O ₃ 0.1 mol% constant Li ₂ O 0.09 mol% constant Total 100 mol% i.e. , FIG. 13 shows V ₁ , R, and ΔV ₁ of various varistors in which the amount of SnO ₂ (mol %) and the amount of ZnO were varied so that the total amount was 100 mol %.

Figure 14 shows the varistor voltage of a varistor with the following composition.
V ₁ , voltage ratio R, and voltage change rate ΔV ₁ are shown.

ZnO 78.31-98.26 mol% TiO ₂ 0.05-20 mol% Bi ₂ O ₃ 1 mol% constant Yb ₂ O ₃ 0.5 mol% constant Al ₂ O ₃ 0.1 mol% constant Li ₂ O 0.09 mol% constant Total 100 mol% i.e. , FIG. 14 shows various varistors V ₁ , R, ΔV ₁ in which the amount of TiO ₂ (mol %) and the amount of ZnO were varied so that the total amount was 100 mol %.

Figure 15 shows the varistor voltage of a varistor with the following composition.
V ₁ , voltage ratio R, and voltage change rate ΔV ₁ are shown.

ZnO 78.31-98.26 mol% GeO ₂ 0.05-20 mol% Bi ₂ O ₃ 1 mol% constant Yb ₂ O ₃ 0.5 mol% constant Al ₂ O ₃ 0.1 mol% constant Li ₂ O 0.09 mol% constant Total 100 mol% i.e. , FIG. 15 shows V ₁ , R, and ΔV ₁ of various varistors in which the amount of GeO ₂ (mol %) and the amount of ZnO were varied so that the total amount was 100 mol %.

Figure 16 shows the varistor voltage of a varistor with the following composition.
V ₁ , voltage ratio R, and voltage change rate ΔV ₁ are shown.

ZnO 78.31 to 98.26 mol% Sb ₂ O ₃ 0.05 to 20 mol% Bi ₂ O ₃ 1 mol% constant Yb ₂ O ₃ 0.5 mol% constant Al ₂ O ₃ 0.1 mol% constant Li ₂ O 0.09 mol% constant Total 100 mol % That is, FIG. 16 shows various varistors V ₁ , R, and ΔV ₁ in which the amount of Sb ₂ O ₃ (mol %) and the amount of ZnO were changed so that the total amount was 100 mol %.

Figure 17 shows the varistor voltage of a varistor with the following composition.
V ₁ , voltage ratio R, and voltage change rate ΔV ₁ are shown.

ZnO 78.31-98.26 mol% B ₂ O ₃ 0.05-20 mol% Bi ₂ O ₃ 1 mol% constant Yb ₂ O ₃ 0.5 mol% constant Al ₂ O ₃ 0.1 mol% constant Li ₂ O 0.09 mol% constant Total 100 mol % That is, FIG. 17 shows V ₁ , R, and ΔV ₁ of various varistors in which the amount of B ₂ O ₃ (mol %) and the amount of ZnO were changed so that the total amount was 100 mol %.

Figure 18 shows the varistor voltage of a varistor with the following composition.
V ₁ , voltage ratio R, and voltage change rate ΔV ₁ are shown.

ZnO 78.31 to 98.26 mol% Cr ₂ O ₃ 0.05 to 20 mol% Bi ₂ O ₃ 1 mol% constant Yb ₂ O ₃ 0.5 mol% constant Al ₂ O ₃ 0.1 mol% constant Li ₂ O 0.09 mol% constant Total 100 mol % That is, FIG. 18 shows V ₁ , R, and ΔV ₁ of various varistors in which the amount of Cr ₂ O ₃ (mol %) and the amount of ZnO were changed so that the total amount was 100 mol %.

Figure 19 shows the varistor voltage of a varistor with the following composition.
V ₁ , voltage ratio R, and voltage change rate ΔV ₁ are shown.

ZnO 78.31 to 98.26 mol% CoO + MnO 0.05 to 20 mol% Bi ₂ O ₃ 1 mol% constant Yb ₂ O ₃ 0.5 mol% constant Al ₂ O ₃ 0.1 mol% constant Li ₂ O 0.09 mol% constant Total 100 mol% i.e. Figure 19 shows the amount (mol%) of CoO + MnO (equimolar mixture) and the amount so that the total is 100 mol%.
V ₁ , R, of various varistors with varying amounts of ZnO,
Indicates △V ₁ .

Figure 20 shows the varistor voltage of a varistor with the following composition.
V ₁ , voltage ratio R, and voltage change rate ΔV ₁ are shown.

ZnO 78.31 to 98.26 mol% CoO + SiO ₂ + Sb ₂ O ₃ 0.05 to 20 mol% Bi ₂ O ₃ 1 mol% constant Yb ₂ O ₃ 0.5 mol% constant Al ₂ O ₃ 0.1 mol% constant Li ₂ O 0.09 mol% constant Total 100 mol% In other words, Figure 20 shows the amounts (mol%) of CoO + SiO ₂ + Sb ₂ O ₃ (equimolar mixture) and the amount of ZnO changed to a total of 100 mol% of various varistors.
V ₁ , R, and ΔV ₁ are shown.

Figure 21 shows the varistor voltage of a varistor with the following composition.
V ₁ , voltage ratio R, and voltage change rate ΔV ₁ are shown.

ZnO 77.81-97.76 mol% Yb ₂ O ₃ 0.05-20 mol% Bi ₂ O ₃ 1 mol% constant CoO 1 mol% constant Al ₂ O ₃ 0.1 mol% constant Li ₂ O 0.09 mol% constant Total 100 mol% i.e. FIG. 21 shows V ₁ , R, and ΔV ₁ of various varistors in which the amount of Yb ₂ O ₃ (mol %) and the amount of ZnO were varied so that the total amount was 100 mol %.

Figure 22 shows the varistor voltage of a varistor with the following composition.
V ₁ , voltage ratio R, and voltage change rate ΔV ₁ are shown.

ZnO 77.81-97.76 mol% Er ₂ O ₃ 0.05-20 mol% Bi ₂ O ₃ 1 mol% constant CoO 1 mol% constant Al ₂ O ₃ 0.1 mol% constant Li ₂ O 0.09 mol% constant Total 100 mol% i.e. FIG. 22 shows V ₁ , R, and ΔV ₁ of various varistors in which the amount of Er ₂ O ₃ (mol %) and the amount of ZnO were varied so that the total amount was 100 mol %.

Figure 23 shows the varistor voltage of a varistor with the following composition.
V ₁ , voltage ratio R, and voltage change rate ΔV ₁ are shown.

ZnO 77.81-97.76 mol% Y ₂ O ₃ 0.05-20 mol% Bi ₂ O ₃ 1 mol% constant CoO 1 mol% constant Al ₂ O ₃ 0.1 mol% constant Li ₂ O 0.09 mol% constant Total 100 mol% i.e. FIG. 23 shows various varistors V ₁ , R, and ΔV ₁ in which the amount of Y ₂ O ₃ (mol %) and the amount of ZnO were varied so that the total amount was 100 mol %.

Figure 24 shows the varistor voltage of a varistor with the following composition.
V ₁ , voltage ratio R, and voltage change rate ΔV ₁ are shown.

ZnO 77.81-97.76 mol% La ₂ O ₃ 0.05-20 mol% Bi ₂ O ₃ 1 mol% constant CoO 1 mol% constant Al ₂ O ₃ 0.1 mol% constant Li ₂ O 0.09 mol% constant Total 100 mol% i.e. FIG. 24 shows V ₁ , R, and ΔV ₁ of various varistors in which the amount of La ₂ O ₃ (mol %) and the amount of ZnO were varied so that the total amount was 100 mol %.

Figure 25 shows the varistor voltage of a varistor with the following composition.
V ₁ , voltage ratio R, and voltage change rate ΔV ₁ are shown.

ZnO 77.81-97.76 mol% Pr ₂ O ₃ 0.05-20 mol% Bi ₂ O ₃ 1 mol% constant CoO 1 mol% constant Al ₂ O ₃ 0.1 mol% constant Li ₂ O 0.09 mol% constant Total 100 mol% i.e. FIG. 25 shows V ₁ , R, and ΔV ₁ of various varistors in which the amount of Pr ₂ O ₃ (mol %) and the amount of ZnO were varied so that the total amount was 100 mol %.

Figure 26 shows the varistor voltage of a varistor with the following composition.
V ₁ , voltage ratio R, and voltage change rate ΔV ₁ are shown.

ZnO 77.81-97.76 mol% Nd ₂ O ₃ 0.05-20 mol% Bi ₂ O ₃ 1 mol% constant CoO 1 mol% constant Al ₂ O ₃ 0.1 mol% constant Li ₂ O 0.09 mol% constant Total 100 mol% i.e. FIG. 26 shows V ₁ , R, and ΔV ₁ of various varistors in which the amount of Nd ₂ O ₃ (mol %) and the amount of ZnO were varied so that the total amount was 100 mol %.

Figure 27 shows the varistor voltage of a varistor with the following composition.
V ₁ , voltage ratio R, and voltage change rate ΔV ₁ are shown.

ZnO 77.81 to 97.76 mol% Yb ₂ O ₃ +La ₂ O ₃ 0.05 to 20 mol% Bi ₂ O ₃ 1 mol% constant CoO 1 mol% constant Al ₂ O ₃ 0.1 mol% constant Li ₂ O 0.09 mol% constant Total 100 Mol% In other words, Figure 27 shows Yb ₂ O ₃ + La ₂ O ₃ (equimolar mixture)
amount (mol%) and total 100 mol%
V ₁ , R, of various varistors with varying amounts of ZnO,
Indicates △V ₁ .

Figure 28 shows the varistor voltage of a varistor with the following composition.
V ₁ , voltage ratio R, and voltage change rate ΔV ₁ are shown.

ZnO 91.8-97.4905 mol% Al ₂ O ₃ 0.005-3 mol% Bi ₂ O ₃ 1 mol% constant CoO 1 mol% constant Yb ₂ O ₃ 0.5 mol% constant Li ₂ O 0.0045-2.7 mol% Total 100 mol% i.e. , Figure 28 shows that the amount of Al ₂ O ₃ (mol%) and the amount of ZnO were changed so that the total was 100 mol%,
In addition, the V ₁ of various varistors in which the amount of Li ₂ O was changed so that the molar ratio of Li ₂ O / Al ₂ O ₃ was maintained at 0.9 as in the case of FIGS. 2 to 27, R, ΔV ₁ is shown.

In Figure 29, Bi ₂ O ₃ is fixed at 1 mol %, CoO is fixed at 1 mol %, Yb ₂ O ₃ is fixed at 0.5 mol %, Al ₂ O ₃ is fixed at 0.1 mol %, and Li ₂ O / Al ₂ O ₃ is V ₁ , R, and ΔV ₁ are shown when the molar ratio is varied in the range of 0.3 to 1.3, and the balance is ZnO, making the total 100 mol%.

Next, the reasons for limiting the composition of the present invention will be explained.

In Figures 2, 3, and 4, the second
When Bi ₂ O ₃ as a component exceeds 3 mol %, the voltage ratio R is large and the absolute value of the voltage change rate ΔV ₁ is also large. Furthermore, the elements adhere to each other, resulting in poor yield. On the other hand, when BiO ₂ is less than 0.1 mol%,
R is large, and the absolute value of △V ₁ is also large. On the other hand, when the second component is in the range of 0.1 to 3 mol %, R is 3 or less and the absolute value of ΔV ₁ is 10% or less. Therefore, the preferred range of the second component is 0.1 to
It is 3 mol%. Further, a more preferable range of the second component is that R is 2.5 or more and the absolute value of △V ₁ is 6.
The content is 0.2 to 2 mol%.

In FIGS. 5 to 20, the absolute values of R and ΔV ₁ are large for those containing more than 10 mol % of the third component and those containing less than 0.1 mol %. On the other hand, if the third component is in the range of 0.1 to 10 mol%,
R is 3 or less, and the absolute value of ΔV ₁ is 10% or less. Therefore, the preferred range of the third component is 0.1 to
It is 10 mol%. Further, when the third component is in the range of 0.5 to 5 mol%, the absolute values of R and _ΔV1 become even smaller, so 0.5 to 5 mol% is a more preferable range.

In FIGS. 21 to 27, those in which the fourth component exceeds 3 mol % and those in which it is less than 0.01 mol % have a large R and a large absolute value of ΔV ₁ . On the other hand, in the range of 0.01 to 3 mol%,
R is 3 or less, and the absolute value of △V ₁ is 10% or less.
Therefore, the preferred range of the fourth component is 0.01 to 3 mol%. Moreover, the more preferable range is R and Δ
It is 0.05 to 2 mol %, which further reduces the absolute value of V ₁ .

In FIG. 28, those in which the fifth component (Al ₂ O ₃ ) exceeds 1 mol % and those in which it is less than 0.01 mol % have a large R and a large absolute value of ΔV ₁ .
On the other hand, in the range of 0.01 to 1 mol%, R is 2
Below, the absolute value of △V ₁ becomes 10% or less. Therefore,
The preferred range of the fifth component is 0.01 to 1 mol%. Further, a more preferable range is R and △V ₁
The absolute value of is further reduced at 0.05 to 0.5 mol%.

In Figure 29, the molar ratio of Li ₂ O/Al ₂ O ₃ is
Anything over 1.1 and less than 0.5 is
It has a large R and a large absolute value of ΔV ₁ .
On the other hand, if the molar ratio is in the range of 0.5 to 1.1, R will be 3 or less and the absolute value of ΔV ₁ will be 10% or less. In FIG. 29, Al ₂ O ₃ is set at 0.1 mol %, but the same tendency occurs when Al ₂ O ₃ is set at 0.01 to 1 mol %. Therefore, the preferred molar ratio range is 0.5 to 1.1. In addition, a more preferable molar ratio range is 0.8, which further reduces the absolute values of R and △V ₁ .
~1.0, and the most preferred molar ratio is around 0.9. By determining the molar ratio range as described above, the range of Li ₂ O is 0.005 to 1.1 mol %.

As mentioned above, once the range of other components other than ZnO is determined, the amount (mol%) of ZnO is the remainder and is necessarily 81.9 to 99.775 mol%. In addition, in FIGS. 2 to 29, similar trends can be obtained even if the amount (mol %) of the fixed component is changed. Further, even if the types of oxides of the third and fourth components are changed, the same tendency will be exhibited since the oxides of the same group perform almost the same function.

Although the embodiments of the present invention have been described above, the present invention is not limited thereto and can be further modified. For example, other substances may be added in small amounts as long as the purpose of the present invention is not impaired.

Effects of the Invention As is clear from the above, according to the present invention, the voltage ratio R is about 1.45 to 3, and the absolute value of the voltage change rate △V ₁ is
It is possible to provide a varistor with a varistor voltage V ₁ of about 35 to 245 V, with a varistor voltage V 1 of 10% or less. In addition, the voltage ratio R
is determined by the voltage of the varistor current 1mA and 5A, so it is possible to know the nonlinearity in the large current region.In the present invention, since this is small, the voltage nonlinearity in the large current region can be determined. big. Furthermore, since the absolute value of the voltage change rate ΔV ₁ is small, it has excellent surge resistance.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view schematically showing the arrangement of sintered crystal particles of an oxide voltage nonlinear resistor according to the present invention;
Figure 2 is a characteristic curve diagram showing changes in varistor voltage _{V 1 ,} voltage ratio R, and voltage change rate △V ₁ with respect to changes in Bi ₂ O 3 (mol %), and Figure 3 also shows changes in Bi ₂ O ₃ (mol %). Figure 4 is also a characteristic curve diagram showing changes in varistor voltage V ₁ , voltage ratio R, and voltage change rate △V ₁ with respect to changes in .
Varistor voltage V ₁ for changes in Bi ₂ O ₃ (mol %),
Characteristic curve diagram showing changes in voltage ratio R and voltage change rate △V _1. Figure 5 shows characteristics showing changes in varistor voltage V ₁ , voltage ratio R, and voltage change rate △V ₁ with respect to changes in CoO (mol%). The curve diagram, Figure 6 is a characteristic curve diagram showing changes in varistor voltage V ₁ , voltage ratio R, and voltage change rate △V ₁ with respect to changes in MnO (mol%), and Figure 7 is
Varistor voltage V ₁ for changes in MgO (mol %),
A characteristic curve diagram showing changes in voltage ratio R and voltage change rate △V _1. Figure 8 shows characteristics showing changes in varistor voltage V ₁ , voltage ratio R, and voltage change rate △V ₁ with respect to changes in CaO (mol%). Curve diagram. Figure 9 is a characteristic curve diagram showing changes in varistor voltage V ₁ , voltage ratio R, and voltage change rate △V ₁ with respect to changes in SrO (mol%). Figure 10 is a characteristic curve diagram showing changes in BaO (mol%). varistor voltage
A characteristic curve diagram showing changes in V ₁ , voltage ratio R, and voltage change rate △V ₁ . Figure 11 shows the varistor voltage V ₁ , voltage ratio R, and voltage change rate △ with respect to changes in NiO (mol%).
A characteristic curve diagram showing changes in V ₁ , FIG. 12 is a characteristic curve diagram showing changes in varistor voltage V ₁ , voltage ratio R, and voltage change rate △V ₁ with respect to changes in SiO ₂ (mol%),
Figure 13 is a characteristic curve diagram showing changes in varistor voltage V ₁ , voltage ratio R, and voltage change rate △V 1 with respect to changes in SnO ₂ (mol%), and Figure 14 is a characteristic curve diagram showing changes in varistor voltage V 1 , voltage ratio R, and voltage change rate △V ₁ with respect to changes in SnO ₂ (mol%). Figure 15 is a characteristic curve diagram showing changes in voltage V ₁ , voltage ratio R, and voltage change rate △V ₁ .
Varistor voltage V ₁ for changes in GeO ₂ (mol %),
A characteristic curve diagram showing changes in voltage ratio R and voltage change rate △V _1. Figure 16 shows varistor voltage V ₁ , voltage ratio R, and voltage change rate △V ₁ with respect to changes in Sb ₂ O ₃ (mol%).
A characteristic curve diagram showing changes in B ₂ O ₃ (mol%), varistor voltage V ₁ , voltage ratio R,
Characteristic curve diagram showing changes in voltage change rate △V ₁ , 1st
Figure 8 is a characteristic curve diagram showing changes in varistor voltage V ₁ , voltage ratio R, and voltage change rate △V ₁ with respect to changes in Cr ₂ O ₃ (mol%), and Figure 19 is the total of CoO and MnO (mol%) A characteristic curve diagram showing changes in varistor voltage V ₁ , voltage ratio R, and voltage change rate △V ₁ with respect to changes in ,
Figure 20 shows the total of CoO, SiO ₂ and Sb ₂ O ₃ (mol%)
Characteristic curve diagram showing changes in varistor voltage V ₁ , voltage ratio R, and voltage change rate △V ₁ with respect to changes in , 21st
The figure is a characteristic curve diagram showing changes in varistor voltage V ₁ , voltage ratio _R , and voltage change rate △V ₁ with respect to changes in Yb ₂ O ₃ (mol %), and Figure 22 shows changes in Er ₂ O 3 (mol %). Figure 23 is a characteristic curve diagram showing changes in varistor voltage V ₁ , voltage ratio R, and voltage change rate △V ₁ with respect to
Varistor voltage V ₁ for changes in Y ₂ O ₃ (mol %),
A characteristic curve diagram showing changes in voltage ratio R and voltage change rate △V _1. Figure 24 shows varistor voltage V ₁ , voltage ratio R, and voltage change rate △V ₁ with respect to changes in La ₂ O ₃ (mol%).
FIG. 25 is a characteristic curve diagram showing changes in varistor voltage V ₁ , voltage ratio R, and voltage change rate △V ₁ with respect to changes in Pr ₂ O ₃ (mol %);
FIG. 26 is a characteristic curve diagram showing changes in varistor voltage V ₁ , voltage ratio R, and voltage change rate ΔV ₁ with respect to changes in Nd ₂ O _{3 (} mol% ₎ , and _FIG . Varistor voltage V ₁ for a change in the sum (mol%) of ₃ ,
A characteristic curve diagram showing changes in voltage ratio R and voltage change rate △V _1. Figure 28 shows varistor voltage V ₁ , voltage ratio R, and voltage change rate △V ₁ with respect to changes in Al ₂ O ₃ (mol%).
Figure 29 is a characteristic curve diagram showing the changes in Li ₂ O and
Varistor voltage V ₁ for changes in the molar ratio of Al ₂ O ₃ ,
It is a characteristic curve diagram showing changes in voltage ratio R and voltage change rate ΔV ₁ . 1...Crystal, 2...High resistance layer, 3...Electrode.

Claims (1)

[Claims] 1 Zn, Bi, Co, Mn, Mg, Ca, Sr, Ba, Ni,
Si, Sn, Ti, Ge, Sb, B, Cr, Yb, Er, Y,
La, Pr, Nd, Al, Li, these representative oxides ZnO, Bi ₂ O ₃ , CoO, MnO, MgO, CaO,
SrO, BaO, NiO, _SiO2 , _SnO2 , _TiO2 , _GeO2 ,
Sb ₂ O ₃ , B ₂ O ₃ , Cr ₂ O ₃ , Yb ₂ O ₃ , Er ₂ O ₃ , Y ₂ O ₃ ,
Composition calculated as La ₂ O ₃ , Pr ₂ O ₃ , Nd ₂ O ₃ , Al ₂ O ₃ , Li ₂ O, ZnO 81.9-99.775 mol%, Bi ₂ O ₃ 0.1-3 mol% CoO, MnO, MgO, CaO, SrO, BaO, NiO,
0.1 _to 10 mol% of oxide of one or more of _SiO2 , _{SnO2 , TiO2} , _{GeO2 , Sb2O3} , _{B2O3 and Cr2O3} , _Yb2O3 , _{Er2O3 ,} Y ₂ O ₃ , La ₂ O ₃ , Pr ₂ O ₃ and
0.01 to 3 mol% of one or more oxides of Nd ₂ O ₃ , 0.01 to 1 mol% of Al ₂ O ₃ , 0.005 to 1.1 mol% of Li ₂ O (however, the mol of Li ₂ O/Al ₂ O ₃ An oxide voltage nonlinear resistor made of a sintered body with a ratio of 0.5 to 1.1).