Effects of Aluminum Doping on the Microstructure and Electrical Properties of ZnO- Pr6O11-Co3O4-MnCO3-Y2O3 Varistor Ceramics
来源期刊：Journal Of Wuhan University Of Technology Materials Science Edition2014年第2期
论文作者：王茂华 ZHANG Bo LI Gang YAO Chao
文章页码：246 - 249
摘 要：The effect of Al2O3 doping on the microstructure and electrical properties of the ZnO-Pr6O11-Co3O4-MnCO3-Y2O3 system was investigated in the range of 0.0-0.1mol%. The results reveal that Al2O3 doping has slight influence on the densification process. The microstructure of the ceramics comprises of ZnO phase, ZnAl2O4 spine phase and Pr-rich phases. The addition of Al2O3 greatly affects the electrical properties. The varistor voltage（E1mA/cm2） of ZPCMYAl samples decreases over a wide range from 5 530 V/cm to 1 844 V/cm with the increasing Al2O3 content. The nonlinear exponent（α） increases with the increasing Al2O3 content to 0.01mol%, whereas it is decreased by the further doping. The ZPCMYAl-based varistor ceramics with 0.01mol% Al2O3 exhibit the best electrical properties, with the nonlinear exponent（α） attaining the highest value of 33.4 and the lowest leakage current of 2.7 μA. The capacitance-voltage（C-V） measurement shows that the donor density（N d） at the grain boundaries increase from 1.58×1018 to 3.15×1018 cm-3, the barrier height（j b） increases from 1.60 to 2.36 eV, and the depletion layer width（t） decreases from 24.9 to 21.6 nm.
王茂华1,2，ZHANG Bo1，LI Gang1，YAO Chao1
1. School of Chemistry and Chemical Engineering, Changzhou University
摘 要：The effect of Al2O3 doping on the microstructure and electrical properties of the ZnO-Pr6O11-Co3O4-MnCO3-Y2O3 system was investigated in the range of 0.0-0.1mol%. The results reveal that Al2O3 doping has slight influence on the densification process. The microstructure of the ceramics comprises of ZnO phase, ZnAl2O4 spine phase and Pr-rich phases. The addition of Al2O3 greatly affects the electrical properties. The varistor voltage（E1mA/cm2） of ZPCMYAl samples decreases over a wide range from 5 530 V/cm to 1 844 V/cm with the increasing Al2O3 content. The nonlinear exponent（α） increases with the increasing Al2O3 content to 0.01mol%, whereas it is decreased by the further doping. The ZPCMYAl-based varistor ceramics with 0.01mol% Al2O3 exhibit the best electrical properties, with the nonlinear exponent（α） attaining the highest value of 33.4 and the lowest leakage current of 2.7 μA. The capacitance-voltage（C-V） measurement shows that the donor density（N d） at the grain boundaries increase from 1.58×1018 to 3.15×1018 cm-3, the barrier height（j b） increases from 1.60 to 2.36 eV, and the depletion layer width（t） decreases from 24.9 to 21.6 nm.
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