ZnO varistors made from powders produced utilizing a urea process
Small-grained oxide powders of uniform composition, ideally suited for varistor production, have been prepared as follows: ZnO and other components are dissolved in nitric acid. Urea is added and the mixture is heated to remove water and nitrates and to form solid melamine. The melamine is then calcined to burn off the organics and to produce fine oxide powders. Grain sizes, densities, and electrical characteristics have been measured for varistors fabricated from these powders by sintering or hot pressing. The densities and grain sizes increase with processing temperature, the nonlinearity coefficient depends primarily on composition, and the average voltage per barrier for sintered samples is approximately 2.5 eV. The breakdown field for hot-pressed samples is not uniform for different slices of the same varistor and depends on variables other than the grain size.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 5331308
- Report Number(s):
- ORNL/TM-9728; ON: DE85018076
- Country of Publication:
- United States
- Language:
- English
Similar Records
A process for the chemical preparation of high-field ZnO varistors
Process for the chemical preparation of high-field ZnO varistors
Related Subjects
SEMICONDUCTOR RESISTORS
PRODUCTION
ZINC OXIDES
CHEMICAL PREPARATION
DENSITY
GRAIN SIZE
HOT PRESSING
MELAMINE
POWDERS
SINTERED MATERIALS
UREA
AMIDES
AMINES
AZINES
CARBONIC ACID DERIVATIVES
CHALCOGENIDES
CRYSTAL STRUCTURE
ELECTRICAL EQUIPMENT
EQUIPMENT
FABRICATION
HETEROCYCLIC COMPOUNDS
MATERIALS
MATERIALS WORKING
MICROSTRUCTURE
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PRESSING
RESISTORS
SEMICONDUCTOR DEVICES
SIZE
SYNTHESIS
TRIAZINES
ZINC COMPOUNDS
420800* - Engineering- Electronic Circuits & Devices- (-1989)