Effects of additives and secondary phases on the sintering behavior of zinc oxide-based varistors
Resource
Materials Chemistry and Physics 62 (2): 164-168
Journal
Materials Chemistry and Physics
Journal Volume
62
Journal Issue
2
Pages
164-168
Date Issued
2000
Date
2000
Author(s)
Abstract
The influence of additives and secondary phases on the sintering behavior of zinc oxide-based varistors has been investigated in this study. Addition of Bi2O3 and Sb2O3 to ZnO results in rapid shrinkage of the specimens at around 1000 °C. This rapid shrinkage is attributed to the reaction between the pyrochlore phase and ZnO. This reaction has been verified by investigating the system of ZnO and a synthesized pyrochlore phase ZnBi1.5Sb1.5O7. This pyrochlore phase has a cubic symmetry, with a lattice parameter ao = 10.4438 angstroms. ZnBi1.5Sb1.5O7 is found to react with ZnO at 1000 °C to lead to the formation of Bi2O3, which accelerates the sintering rate of ZnO through a liquid-phase sintering mechanism. On the other hand, the spinel phase α-Zn7Sb2O12 hinders the sintering process as well as the grain growth of ZnO.
Type
journal article
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