Effects of high-energy ball milling oxide-doped and varistor ceramic powder on ZnO varistor
(1. School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, China;
2. Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors,
Chinese Academy of Sciences, Beijing 100083, China;
3. State Key Laboratory of Electrical Insulation and Power Equipment,
Xi’an Jiaotong University, Xi’an 710049, China;
4. Changzhou Engineering Research Institute of Jiangsu University, Changzhou 213000, China;
5. State Key Laboratory of Inorganic Synthesis and Preparative Chemistry,
College of Chemistry, Jilin University, Changchun 130012, China)
2. Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors,
Chinese Academy of Sciences, Beijing 100083, China;
3. State Key Laboratory of Electrical Insulation and Power Equipment,
Xi’an Jiaotong University, Xi’an 710049, China;
4. Changzhou Engineering Research Institute of Jiangsu University, Changzhou 213000, China;
5. State Key Laboratory of Inorganic Synthesis and Preparative Chemistry,
College of Chemistry, Jilin University, Changchun 130012, China)
Abstract: ZnO varistor ceramics doped with Bi2O3, Sb2O3, Co2O3, Cr2O3, and MnO2 were prepared separately by two high-energy ball milling processes: oxide-doped and varistor ceramic powder. A comparison in the electrical and microstructural properties of the samples obtained by both methods was made. The best results on these characteristics were achieved through the high-energy ball milling varistor ceramic powder route, obtaining a nonlinear coefficient of 57 and a breakdown field of 617 V/mm at a sintering temperature of 1000 °C for 3 h. The samples synthesized by this technique show not only high density value, 95% of the theoretical density, but also a homogeneous microstructure, which compete with those obtained by the high-energy ball milling oxide-doped powder route. With the advantage that the high-energy ball milling varistor ceramic powder route can refine grain, increase the driving force of sintering, accelerate the sintering process, and reduce the sintering temperature.
Key words: varistor; ZnO; high-energy ball milling; electrical characteristic; microstructure