JPH04175259A - Voltage-nonlinear resistance ceramic composition - Google Patents

Abstract

PURPOSE:To obtain a voltage-nonlinear resistance ceramic composition for low-voltage use having excellent resistance to surge current by using zinc oxide as a main component, adding specific amounts of oxides of Bi, Co, Mn, Sb, etc., as subsidiary components and adding oxides of Th, Gd, Yb, etc., to the obtained composition. CONSTITUTION:The objective voltage-nonlinear resistance ceramic composition for low-voltage use is produced by including 0.01-3.00mol% of at least one kind of Th, Gd and Yb in terms of ThO2, Gd2O3 and Yb2O3 in a composition composed mainly of ZnO and containing at least Bi, Co, Mn and Sb as subsidiary components in amounts of 0.1-3.0mol% each of Bi2O3, Co2O3 and MnO2 in terms of Bi2O3, Co2O3 and MnO2, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a voltage nonlinear resistor ceramic composition that is applied to stabilize circuit voltage of various electronic devices, absorb surges, and noise, etc. .

Zinc oxide (
ZnO varistors whose main component is ZnO are generally known. This ZnO varistor has characteristics such as good voltage nonlinearity and large surge current withstand capacity. The manufacturing method involves adding a trace amount of B 1203. to ZnO. C
o2O3, MnO:.

Add and mix Sb2O3, 5i02, etc., and after molding, 10
It is obtained by sintering at 00 to 1300°C. Any desired varistor voltage can be obtained depending on the types and ratios of the trace components.

The varistor voltage of this ZnO varistor is proportional to the element thickness, and in order to obtain a high varistor voltage, the thickness may be increased. Therefore, in order to downsize the device, it is necessary to increase the varistor voltage per unit thickness (Vl-A/m). Among the trace components mentioned above, silicon oxide (SiC2) in particular suppresses grain growth of Zn○ and increases V+m
It is widely known as a component that increases A/nun.

Problems to be Solved by the Invention However, in the case of a composition using conventional 5i (h), its high specific gravity is extremely light compared to other components, and even if a sedimentary material is used, it is not sufficiently pulverized, and as a result, sintering The problem was that voids were generated in the body, reducing the ability to withstand surge currents.

The present invention solves these conventional problems, and provides a V lffi A with excellent surge current resistance.
The purpose of the present invention is to provide a high (200V or more) voltage nonlinear resistor of 1111.

Means for Solving the Problems In order to achieve this object, the voltage nonlinear resistor ceramic composition of the present invention is composed of Zn○, B 1203. Co2O3゜M
In the composition consisting of nO2, Sb2O3, ThO2, Gd2
At least one of O3 and Yb2O3 from 0.01 to 3
．． It contains 00 mol%.

Effect: As a result, Th02. By containing 0.01 to 3.00 mol% of at least one of Gd2O3 and YbpO3, the surge current withstand capacity is improved, and VIIIA
/1111 becomes high, so the device can be significantly downsized.

Example Hereinafter, the present invention will be explained in detail according to examples.

First, add Bi2O3, Co2O3, MnO2゜S to Zn○.
b203. S i 02. Th 02. G d2
03. Yb2o3 was blended in the ratios shown in Table 1 below.

This powder was wet mixed and pulverized using a ball mill, an organic binder was added and mixed, and granulation was performed using a spray dryer. The granulated powder was molded at a pressure of 1000 kg/'cnf, and the diameter was 13wffR and the thickness was 1.311111.
A molded body was obtained. After baking this at 1150°C for 3 hours, Ag electrodes were baked at 450 to 850°C on both end faces, and lead wires were soldered. Finally, it was coated with a thermosetting resin and used as a sample.

For the above samples, the varistor voltage (V
IIIA/wn) and the voltage nonlinear coefficient (α) were measured, and the results are also shown in Table 1. In Table 1, vl, A
/Wffl is the thickness I of the element when a current of 1 mA is applied.
Indicates the voltage between terminals per I. Also, α is 1mA and 100
It was calculated using the following formula from the varistor voltage when each μA current was applied.

However, the varistor voltage at I+, I:: measurement current v,, v, : I l+ I,, +:: Also, the 8/20 specified by JEC for each sample
A surge current of 3000 A was applied twice with a standard waveform of μs, and the varistor voltage was measured. Table 1 shows the varistor voltage and the rate of change of the initial value (ΔV11IIA) at that time.

(Left below) From the results in Table 1, Birch is 0.1 mo Q. If it is less than 3.0 mol %, ΔVl+*A becomes large, and if it exceeds 3.0 mol %, α becomes small and ΔVImA also becomes large. Also,
When the amount of Co2O3 and MnO2 is less than 0.1 mol 90 or more than 3.0 mol %, α decreases and Δv11I^ also increases. Furthermore, when Sb2O3 is less than 0.5 mol%, V111A/Ill! 1 is low, ΔV1mA also becomes large, and if it exceeds 3.0 mol%, α becomes worse. When ThO:, Gd2O3, yb, o3 is less than 0.01 mol%, V+mA/mm is low and ΔvleA is also large. Moreover, if it exceeds 3.00 mol%, α becomes worse,
Δv1□A also increases.

In addition, N i O, Cr203°5n02. A +203. By adding B2O5, MgO, etc., nonlinearity can be further improved.

Above and beyond the effects of the invention, Th02. Gdzo3. Yb:03
By containing 0.01 to 3.00 mol O9 of at least one of these, it is possible to provide an excellent surge current withstand capacity, a high varistor voltage per unit, and a small voltage nonlinear resistor.

Claims (1)

[Scope of Claims] Zinc oxide is the main component, and at least bismuth, cobalt, manganese, and antimony are added as subcomponents.
_2O_3, Co_2O_3, MnO_2, Sb_2O
In terms of _3, the composition consists of Bi_2O_3 0.1-3.0 mol% Co_2O_3 0.1-3.0 mol% MnO_2 0.1-3.0 mol% Sb_2O_3 0.5-3.0 mol% , at least one of thorium, gadolinium, and ytterbium as ThO_2 and Gd, respectively.
_2O_3, converted to Yb_2O_3, 0.01 to 3
．． A voltage nonlinear resistor ceramic composition characterized by containing 00 mol%.