Process for the chemical preparation of high-field ZNO varistors
This patent describes a process for the production of a varistor precursor by intimate mixing of zinc oxide, bismuth oxide, and at least one additional metal oxide dopant, the improvement comprising: mixing the oxides by (a) precipitating zinc or coprecipitating zinc and at least one additional metal from a solution of chloride salts by means of an inorganic hydroxide, (b) converting the precipitate to oxides by calcining at 400-600 degrees C, and (c) precipitating bismuth on the surface of the oxides by contacting with a solution of Bi dissolved in HNO/sub 3/; the additional oxide dopant is MnO, CoO, or a mixture thereof, and where the proportions of oxides in the resulting precursor are about: 93-98.5 mole% Zn, 0-1.0 mole% Co, 0-1.2 mole% Mn, 0.1-6.0 mole% Bi.
- Assignee:
- Dept. of Energy, Washington, DC
- Patent Number(s):
- US 4681717
- OSTI ID:
- 6254352
- Resource Relation:
- Patent File Date: Filed date 19 Feb 1986
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SEMICONDUCTOR RESISTORS
CHEMICAL PREPARATION
ZINC OXIDES
BISMUTH
BISMUTH OXIDES
CALCINATION
CHLORIDES
COBALT OXIDES
COPRECIPITATION
DISSOLUTION
DOPED MATERIALS
HIGH TEMPERATURE
HYDROXIDES
MANGANESE OXIDES
MIXING
NITRIC ACID
ZINC
BISMUTH COMPOUNDS
CHALCOGENIDES
CHEMICAL REACTIONS
CHLORINE COMPOUNDS
COBALT COMPOUNDS
DECOMPOSITION
ELECTRICAL EQUIPMENT
ELEMENTS
EQUIPMENT
HALIDES
HALOGEN COMPOUNDS
HYDROGEN COMPOUNDS
INORGANIC ACIDS
MANGANESE COMPOUNDS
MATERIALS
METALS
OXIDES
OXYGEN COMPOUNDS
PRECIPITATION
PYROLYSIS
RESISTORS
SEMICONDUCTOR DEVICES
SEPARATION PROCESSES
SYNTHESIS
THERMOCHEMICAL PROCESSES
TRANSITION ELEMENT COMPOUNDS
ZINC COMPOUNDS
360601* - Other Materials- Preparation & Manufacture