Premium
Effect of ZrO 2 addition on tolerance characteristics of the electrical degradation of ZnO varistors
Author(s) -
Akiyama Yuji,
Takada Masayuki,
Fukumori Ai,
Sato Yuuki,
Yoshikado Shinzo
Publication year - 2012
Publication title -
electrical engineering in japan
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.136
H-Index - 28
eISSN - 1520-6416
pISSN - 0424-7760
DOI - 10.1002/eej.21228
Subject(s) - materials science , varistor , scanning electron microscope , degradation (telecommunications) , tetragonal crystal system , monoclinic crystal system , non blocking i/o , wurtzite crystal structure , chemical engineering , composite material , metallurgy , zinc , electronic engineering , crystallography , crystal structure , voltage , electrical engineering , chemistry , biochemistry , engineering , catalysis
Abstract 3 ZnO varistors with excellent electrical degradation tolerance characteristics were made by addition of Bi 2 O 3 ‐MnO 2 ‐Co 3 O 4 ‐Cr 2 O 3 ‐SiO 2 ‐Sb 2 O 3 ‐NiO. The electrical degradation tolerance characteristics were evaluated by varying the amount of ZrO 2 . The evaluation methods were voltage–current ( V – I ) characteristics, X‐ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersion X‐ray spectroscopy (EDX). Monoclinic and tetragonal ZrO 2 and compounds derived from Zr were observed at both the grain boundaries and triple points. Moreover, the compounds derived from Zr with added Sb showed improved electrical degradation tolerance characteristics. On the other hand, monoclinic ZrO 2 in particular degraded the electrical degradation tolerance characteristics. One factor in the improvement of the electrical degradation tolerance characteristics is that the mobility of oxide ions or interstitial Zn 2+ ions might be hindered by the formation of compounds containing Zr, Sb, Si, and Bi atoms. The electrical degradation tolerance characteristics of ZnO varistors with added ZrO 2 were better than those of varistors without addition of ZrO 2 but subjected to heat treatment. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 179(2): 11–19, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21228