JPS58194301A - Voltage non-linear resistor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a voltage nonlinear resistor, and particularly to a voltage nonlinear resistor that has excellent characteristics in a low voltage region and has uniform characteristics.

BACKGROUND ART Conventionally, SiC varistors, Si varistors, and the like have been widely used as voltage nonlinear resistors, so-called Neuristors.

SiC varistors utilize the voltage nonlinear characteristics based on the contact resistance of silicon carbide particles, and have a structure in which many silicon carbide particles are connected vertically and horizontally, and have the advantage of being able to withstand high voltages, but the nonlinearity index α is It has the disadvantage that it is small at a low varistor voltage of about IOV, less than 3.0, and is not very large, less than 7 even at a high voltage. on the other hand,
Si varistors utilize the forward characteristics of a PN junction, and have the advantage of having a large nonlinearity index σ, but the varistor voltage is limited to about O and SV, and a predetermined varistor voltage can be adjusted arbitrarily. The disadvantage is that it cannot be obtained.In recent years,
Zinc oxide varistors made of ceramics containing zinc oxide as a main ingredient have been developed to compensate for the drawbacks seen in SiC varistors and Si varistors, and various varistors with improved characteristics have been proposed. For example, Tokuko Sho 48-423
Publication No. 16 includes BiP3. Coo, MnO, Tie2
Converted to 0.1 to 3.0 mol of bismuth, Kohar) 0.
A voltage nonlinear resistor made of a zinc oxide sintered body containing 1 to 3.0 mol of manganese, 1 to 3.0 mol of manganese, and 0.1 to 30 mol of titanium is disclosed. Although this voltage nonlinear resistor has superior characteristics compared to SiC varistors and Si varistors, and is superior to SiC varistors in terms of productivity, bismuth and cobalt are easily evaporated during the manufacturing process, resulting in variations in characteristics. It has the disadvantage that it is large and the yield is poor.

The present invention has been made in view of such problems, and in particular, it is an object of the present invention to provide a voltage nonlinear resistor that has less variation in characteristics and is excellent in a low voltage region.

The voltage nonlinear resistor according to the present invention uses bismuth as Bi2O
0.1 to 1.0 molti in terms of MnO, manganese in O, 1 to 1.0 molti in terms of MnO, titanium in 0.81 to 1.0 molti in terms of T + 02, and 0.1 to 1.0 molt in tin in terms of S n O2.
It is characterized in that it contains 0.5 to 0.5 mole, and the remainder is essentially zinc oxide.

The reason why the composition of the voltage nonlinear resistor of the present invention is limited as described above is as follows. Bismuth, manganese, titanium, and tin all affect the varistor characteristics and threshold voltage, and since they are bismuth, they were set at 0.1 to 1.0 mol. For manganese, α is small if it is less than 0.1 molti in terms of M n 0, and it was set to 0.1 to 1.0 molti.

In addition, titanium has a high threshold voltage when it is less than O1 molti in terms of T i O3, and when it exceeds 1.0 molti, abnormal grain growth occurs and the characteristics deteriorate, especially α becomes small, so Q, 1 ~ It was made into 10 molti. 0.05 to 0.50 molti in terms of tin is converted to S n 02.
This is because α is small when it is less than 0.5 mol, and the threshold voltage becomes high when it exceeds 0.5 mol.

Examples will be described below.

Example: Bismuth oxide (Bi203) was added to zinc oxide (ZnO) powder.
), oxide 77 (MnO), titanium oxide 9 / (T i
o 2 ) and tin oxide (S n 02 ) in the composition ratios shown in Table 1, and after thoroughly mixing with the organic binder, the powder was heated to a diameter of 10.0 m under a pressure of ROOM/cd. It was molded into a disk with a thickness of 15 crystals. Next, it is fired in air at a temperature of 1100 to 1400°C,
A sample was prepared by baking silver electrodes on both sides of each disk.

For each sample obtained, the threshold voltage (vth),
Nonlinear index (α= l/” g (■l QmA/′v
1mA)) and their standard deviations (σ(Vth),
σ(ct)) was calculated. The results are shown in Table 1. In the table, the black mark indicates a voltage nonlinear resistor outside the scope of the present invention.

Table 1 Chiku 1 Table (Continued) Comparative example Bi2031,0 mole, MnO1,0 mo/L/%, C
O2O305molti, T t O2o, 5 mo/l/
%, Zn097.0 molti was mixed, a voltage nonlinear resistor was manufactured in the same manner as in the example, and its characteristics were measured. The threshold voltage was 26■, σ (Vth) = 06, α
= 18, σ(a) = 4.8.

As is clear from the results of Table 1 and the comparative examples, the voltage nonlinear resistor of the present invention has excellent characteristics in the low voltage region below the threshold voltage of 50V, and This patent is characterized by the excellent effect that the standard deviation of the linearity index is significantly smaller than that of the comparative example, and therefore the variation in characteristics is small and the product yield is high.Applicant: Agent, Murata Manufacturing Co., Ltd.
Patent attorney Aohaku Ao and 1 other person2)

Claims (1)

[Claims] (1) Bismuth is 0.1 to 1.0 molti in terms of old 203, manganese is 0.1 to 1.0 molti in terms of MnO,
A voltage nonlinear resistor containing 0.1 to 1.0 moltch of titanium in terms of 7102, 0.05 to 0.5 molt of tin in terms of SnO2, and the remainder being substantially zinc oxide. .