Microstructure-property relationships of rare-earth--zinc-oxide varistors

Journal Article · Tue Jul 01 04:00:00 EDT 1980 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.328168· OSTI ID:5270666

Williams, P; Krivanek, O L; Thomas, G; Yodogawa, M

The microstructure and properties of ZnO varistors containing Ba, Co, and rare-earth--metal oxides, which give values of ..cap alpha.. (..cap alpha..=d(log I)/d(log V)) as high as 29, are examined. Mean ZnO grain size is 11 ..mu..m, and the grains are uniformly doped with Co. The barium and rare earth metals concentrate into 1.5-..mu..m-wide particles embedded in a matrix of ZnO grains. Within the grains and at grain boundaries, the barium and rare-earth--metal concentration is below the detection limit of the energy-dispersive spectrometer technique (about 0.5%). No intergranular films, amorphous or crystalline, are detected, to within 10 A resolution. These results are shown to be consistent with the grain boundary charge depletion model for the voltage barrier formation and breakdown.

• Research Organization: Department of Materials Science and Mineral Engineering, Materials and Molecular Research Division, Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720
• OSTI ID: 5270666
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 51:7; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
ALKALINE EARTH METALS
AMORPHOUS STATE
BARIUM
CHALCOGENIDES
COBALT
CRYSTAL STRUCTURE
DATA
ELECTRICAL EQUIPMENT
ELEMENTS
EQUIPMENT
FILMS
GRAIN BOUNDARIES
GRAIN SIZE
INFORMATION
METALS
MICROSTRUCTURE
OXIDES
OXYGEN COMPOUNDS
QUANTITY RATIO
RARE EARTHS
RESISTORS
RESOLUTION
SEMICONDUCTOR DEVICES
SEMICONDUCTOR RESISTORS
SIZE
TRANSITION ELEMENTS
ZINC COMPOUNDS
ZINC OXIDES