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X‐ray photoelectron spectroscopic studies on ZnO/Bi 2 O 3 varistors
Author(s) -
Sainkar S. R.,
Badrinarayanan S.,
Sinha A. P. B.,
Date S. K.
Publication year - 1981
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.740030308
Subject(s) - intergranular corrosion , x ray photoelectron spectroscopy , varistor , materials science , sintering , analytical chemistry (journal) , microstructure , phase (matter) , ceramic , layer (electronics) , metallurgy , voltage , chemistry , chemical engineering , composite material , electrical engineering , organic chemistry , chromatography , engineering
The intergranular layer and its microstructure, proposed earlier to behave non‐linearly in the ZnO/Bi 2 O 3 varistor ceramic system, has been studied by XPS. Our results clearly indicate the formation of an intergranular layer rich in Bi 2 O 3 separating the semiconducting ZnO grains. With increase in sintering temperature, XPS results show the enrichment of the intergranular layer (Bi 2 O 3 phase) without an additional phase being formed. The non‐linear coefficient (α) in the current–voltage characteristic increases smoothly up to 1300°C. Afterwards, there is a loss of Bi ions from the Bi 2 O 3 enriched intergranular phase resulting in the decrease of α, and in the characteristic XPS peak intensity.