Electrical Properties and Microstructure of ZnO-Nb2O5-MnO Ceramics Sintered in the Liquid Phase
Effect of several additives to ZnO-Nb205-MnO system on varistor characteristics were investigated. BaO and Si02 improved the varistor characteristics, but Co0 decreased the nonlinear exponent. The specimens with Si02 fired below the eutectic temperature also showed the nonlinear characteristics. The concentration difference of some components between the ZnO grains and the intergranular phases, and the temperature dependence of these distribution coefficients are essential for the appearance of varistor characteristics. Liquid phase sintering and high wettability are very convenient to elevate the characteristics. The addition of CeO2 markedly decreased the electrical resistivity and did not show the nonlinear characteristic. The addition of Pr6011 did not change the electrical properties but improved the stability of current.
KeywordsZinc Oxide Nonlinear Characteristic Liquid Phase Sinter Varistor Characteristic Intergranular Phase
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