Effects of Zr and Y Addition on the Electrical Degradation Characteristics of ZnO Varistors

Abstract:

The effects of the addition of Y or both Y and Zr to Bi-Mn-Co-Sb-Si-Cr-Ni-added ZnO varistors on the varistor voltage and the tolerance characteristics of electrical degradation were investigated. The deterioration of the tolerance characteristics of electrical degradation by the addition of Y was probably caused by an increase in the number of willemite (Zn2SiO4)-type particles or a decrease in the number of spinel (Zn2.33Sb0.67O4)-type particles, but this deterioration was reduced by adding Zr. Moreover, the reduction in the average ZnO grain size due to the addition of Y was a major factor in the increased varistor voltage, and the ZnO grain growth was inhibited by the formation of an un-known compound after adding Y. The varistor voltage of a varistor with 2 mol% added Y increased by approximately 50% compared to a varistor with no Y added.

• Periodical: Key Engineering Materials (Volume 445)
• Pages: 237-240
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.445.237
• Online since: July 2010
• Authors: Yuji Akiyama, Ai Fukumori, Masayuki Takada, Yuuki Sato, Shinzo Yoshikado
• Keywords: Electrical Degradation, Tolerance Characteristics of Electrical Degradation, Varistor Voltage, Y Addition, ZnO Varistor, Zr Additions

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