Process for fabricating ZNO-based varistors
The invention is a process for producing ZnO-based varistors incorporating a metal oxide dopant. In one form, the invention comprises providing a varistor powder mix of colloidal particles of ZnO and metal-oxide dopants including Bi/sub 2/O/sub 3/. The mix is hot-pressed to form a compact at temperatures below 850/sup 0/ C. and under conditions effecting reduction of the ZnO to sub-stoichiometric oxide. This promotes densification while restricting liquid formation and grain growth. The compact then is heated under conditions restoring the zinc oxide to stoichiometric composition, thus improving the varistor properties of the compact. The process produces fine-grain varistors characterized by a high actual breakdown voltage and a high average breakdown voltage per individual grain boundary.
- Assignee:
- The United States of America as represented by the Department of Energy
- Patent Number(s):
- US 4510112
- Application Number:
- TRN: 85-021193
- OSTI ID:
- 5272826
- Resource Relation:
- Patent File Date: Filed date 21 Jan 1983; Other Information: PAT-APPL-459922
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
BISMUTH OXIDES
HOT PRESSING
SEMICONDUCTOR RESISTORS
ZINC OXIDES
CRYSTAL DOPING
GRAIN SIZE
STOICHIOMETRY
BISMUTH COMPOUNDS
CHALCOGENIDES
CRYSTAL STRUCTURE
ELECTRICAL EQUIPMENT
EQUIPMENT
FABRICATION
MATERIALS WORKING
MICROSTRUCTURE
OXIDES
OXYGEN COMPOUNDS
PRESSING
RESISTORS
SEMICONDUCTOR DEVICES
SIZE
ZINC COMPOUNDS
420800* - Engineering- Electronic Circuits & Devices- (-1989)
360101 - Metals & Alloys- Preparation & Fabrication