Effects of additives and secondary phases on the sintering behavior of zinc oxide-based varistors

Authors
Lui, CH Chyi, N Wong, HW Hwang, WJ
Citation
Ch. Lui et al., Effects of additives and secondary phases on the sintering behavior of zinc oxide-based varistors, MATER CH PH, 62(2), 2000, pp. 164-168
Citations number
13
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science","Material Science & Engineering
Journal title
MATERIALS CHEMISTRY AND PHYSICS
ISSN journal
02540584 → ACNP
Volume
62
Issue
2
Year of publication
2000
Pages
164 - 168
Database
ISI
SICI code
0254-0584(20000129)62:2<164:EOAASP>2.0.ZU;2-Y
Abstract
The influence of additives and secondary phases on the sintering behavior o f 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 ar ound 1000 degrees C. This rapid shrinkage is attributed to the reaction bet ween the pyrochlore phase and ZnO. This reaction has been verified by inves tigating the system of ZnO and a synthesized pyrochlore phase ZnBi1.5Sb1.5O 7. This pyrochlore phase has a cubic symmetry, with a lattice parameter a(o ) = 10.4438 Angstrom. ZnBi1.5Sb1.5O7 is found to react with ZnO at 1000 deg rees C to lead to the formation of Bi2O3, which accelerates the sintering r ate of ZnO through a liquid-phase sintering mechanism. On the other hand, t he spinel phase alpha-Zn7Sb2O12 hinders the sintering process as well as th e grain growth of ZnO. (C) 2000 Elsevier Science S.A. All rights reserved.