# US 4,397,773 A · Varistor with tetragonal antimony zinc oxide additive

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- Number: US 4,397,773 A
- Document ID: US4397773A
- Status: Granted
- Kind: A
- Application number: 06/191,314
- Filed: 1980-09-26
- Granted: 1983-08-09
- Earliest claimed: 1980-09-26
- Assignees: General Electric Company
- Inventors: John E. May
- Web page: https://patentgrep.com/patent/US4397773A

## CPC

- H01C 7/112: ZnO type
- Y10T 29/49082: Resistor making
- H01C: RESISTORS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A low varistor voltage, low leakage metal oxide varistor and especially a zinc oxide varistor is provided by adding a few percent of tetragonal antimony zinc oxide to the varistor mixture prior to sintering. A method for manufacturing the additive as well as a method for manufacturing a varistor including the additive are described.

## Claims

### Claim 1

An additive for reducing the varistor voltage and the leakage current of zinc oxide varistors consisting of particulate tetragonal-antimony-zinc-oxide of the form ZnSb.sub.2 O.sub.4.

### Claim 2 (depends on 1)

The additive of claim 1 wherein said particulate antimony zinc oxide has a particle size less than about 50 microns.

### Claim 3 (depends on 1)

The additive of claim 1 wherein said particulate antimony zinc oxide has a particle size between about 5 and about 20 microns.

### Claim 4

A method for making a metal oxide varistor having low voltage and low leakage comprising combining zinc oxide as a major constituent, bismuth oxide and one or more other metal oxides as minor constituents, and a varistor voltage-reducing additive of less than 10 weight percent of particulate tetragonal ZnSb.sub.2 O.sub.4 having a particle size of less than about 50 microns; pressing said combination to form a body; and sintering said body at a temperature of about 1300.degree. C.

### Claim 5

A metal oxide varistor having low varistor voltage and low leakage comprising zinc oxide as a major constituent, bismuth oxide and at least one other metal oxide as minor constituents, and a varistor voltage-reducing additive of from 0.1 to 10% by weight of particulate tetragonal ZnSb.sub.2 O.sub.4.