Effects of Aluminum Doping on the Microstructure and Electrical Properties of ZnO- Pr_6O_(11)-Co_3O_4-MnCO_3-Y_2O_3 Varistor Ceramics

作     者：王茂华 ZHANG Bo LI Gang YAO Chao 

作者机构：School of Chemistry and Chemical Engineering Changzhou University Jiangsu Province Key Laboratory of Fine Petrochemical Industry 

出 版 物：《Journal of Wuhan University of Technology(Materials Science)》 (武汉理工大学学报（材料科学英文版）)

年 卷 期：2014年第29卷第2期

页      面：246-249页

核心收录：

学科分类：08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 

基　　金：Funded by the Changzhou Science and Technology Innovation Project(Nos.CC20110048 and CN20100051) 

主　　题：microstructure electrical properties Al_2O_3 doping varistors 

摘      要：Abstract： The effect of Al_2O_3 doping on the microstructure and electrical properties of the ZnO- Pr_6O11-CO_3O_4-MnCO_3-Y_2O_3 system was investigated in the range of 0.0-0. lmol%. The results reveal that Al_2O_3 doping has slight influence on the densification process. The microstructure of the ceramics comprises of ZnO phase, ZnAl_2O_4 spine phase and Pr-rich phases. The addition of Al_2O_3 greatly affects the electrical properties. The varistor voltage （E_1mA/cm^2） of ZPCMYAl samples decreases over a wide range from 5 530 V/cm to 1 844 V/cm with the increasing Al_2O_3 content. The nonlinear exponent（a） increases with the increasing Al_2O_3 content to 0.01mol%, whereas it is decreased by the further doping. The ZPCMYAI-based varistor ceramics with 0.01mol% Al_2O_3 exhibit the best electrical properties, with the nonlinear exponent （ct） 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 （Nd） at the grain boundaries increase from 1.58×10^18 to 3.15×10^18 cm^-3, the barrier height （Чb） increases from 1.60 to 2.36 eV, and the depletion layer width （t） decreases from 24.9 to 21.6 nm.