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Degradation of Zinc Oxide Varistors

Published online by Cambridge University Press:  15 February 2011

Ken Takahashi
Affiliation:
Hitachi Research Laboratory, Hitachi Ltd., 4026 Kuji-cho, Hitachi-shi, Ibaraki-ken 319–12, Japan
T. Miyoshi
Affiliation:
Hitachi Research Laboratory, Hitachi Ltd., 4026 Kuji-cho, Hitachi-shi, Ibaraki-ken 319–12, Japan
K. Maeda
Affiliation:
Hitachi Research Laboratory, Hitachi Ltd., 4026 Kuji-cho, Hitachi-shi, Ibaraki-ken 319–12, Japan
T. Yamazaki
Affiliation:
Hitachi Research Laboratory, Hitachi Ltd., 4026 Kuji-cho, Hitachi-shi, Ibaraki-ken 319–12, Japan
S. Ohwada
Affiliation:
Kokubu Works, Hitachi Ltd., 1–1–1 Kokubu-cho, Hitachi-shi, Ibaraki-ken 316, Japan
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Abstract

The effect of ambient gases on degradation and rejuvenation of ZnO varistors was investigated from the viewpoint of voltage-current characteristics. Ambient oxygen gas suppressed increases in the leakage current during ac biasing, while it rejuvenated degraded samples. The time dependence of rejuvenation indicated that ion migrations, possibly the desorption and adsorption of oxygen ions at the grain boundaries, occur reversibly in degradation and rejuvenation. Moreover, a noticeable difference was observed between V–I curve shapes after ac biasing in nitrogen and in oxygen atmospheres.

Type
Research Article
Copyright
Copyright © Materials Research Society 1982

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References

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