Research on Mechanism of Improving Electrical Properties of ZnO Varistor Ceramics by Laser Shock Processing
In order to improve electrical properties, annealed ZnO varistor ceramics have been treated by laser shock processing (LSP). Electrical parameters of the annealed ZnO varistor ceramics were measured by CJ1001 Varistor Tester. Morphology and microstructure of the annealed ZnO varistor ceramics were gained by XRD and SEM. The results indicate that compared with the electrical properties of the annealed ZnO varistor ceramics, the voltage gradient of the ZnO varistor ceramics treated by LSP remains the same, the nonlinear coefficient substantially increases by 31.6%, and the leakage current reduces by 33.3%. Meanwhile, the phase composition of the annealed ZnO varistor ceramics is mainly composed of ZnO main phase, Zn2.33Sb0.67O4, β-Bi2O3, and δ-Bi2O3 phase; while the phase composition of the ZnO varistor ceramics remains the above four phases in the compound state (anneal and then LSP), but the content of δ-Bi2O3 phase increases. The increase of δ-Bi2O3 phase content is the main reason for improving the electrical properties of the annealed ZnO varistor ceramics.
Yi-Min Deng, Aibing Yu, Weihua Li and Di Zheng
R. F. Chen et al., "Research on Mechanism of Improving Electrical Properties of ZnO Varistor Ceramics by Laser Shock Processing", Applied Mechanics and Materials, Vols. 37-38, pp. 1045-1049, 2010