Abstract
The degree of phase formation was investigated by Sb2O3 behaviour in the calcination process, and the change of microstructure and breakdown properties due to the phases formation in ZnO varistor. The samples were calcined at several temperatures for 2 h and were sintered at 1150 to 1300 ° C, respectively, for 1 h. After that,V-I characteristics were investigated. Phase analysis by X-ray diffraction and microstructures observation by SEM were done. As a result, spinel phase was not formed and low nonlinear resistance was shown in the samples without Sb2O3. In the samples containing Sb2O3, it was shown that the pyrochlore and spinel phase are formed at the conventional calcination temperature or even below that temperature. This primary spinel phase and the spinel phase transformed from pyrochlore phase in sintering process inhibit ZnO grain growth, and so nonlinear resistances should be changed. Hence ZnO grain growth in ZnO-based varistor system is strongly dependent on the Sb2O3 behaviour in the calcination process.
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Mah, J.P., Choi, J.S. & Paek, S.H. On the phases formation in the calcination process of ZnO varistor. J Mater Sci 25, 3375–3379 (1990). https://doi.org/10.1007/BF00587700
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DOI: https://doi.org/10.1007/BF00587700