Influence of soaking time on nonlinear electrical behavior and dielectric properties of TiO_2-based

• 作 者: MENG Fan-ming LU Fei XIAO Lei
• 机 构: School of Physics and Materials Science,State Key Laboratory of Materials Modification by Laser,Anhu
• 出 处: 中南大学学报（英文版）
• 发表日期: 2004年期
• 关键词: TiO_2 varistor ceramics breakdown voltage nonlinear coefficient dielectric const

The influence of soaking time on the nonlinear electrical behavior and dielectric properties of TiO_2-based varistor ceramics was investigated. Based on single sintering process, six disk samples of (Sr, Bi, Si, Ta)-doped TiO_2-based varistor ceramics were fabricated by sintering at 1 250℃ for 0.5-5.0 h. The samples were characterized by X-ray diffraction, voltage-current characteristics, energy spectra, metallographs, breakdown voltages, and apparent dielectric constant. It is found that the breakdown electrical field intensity at a current density of 10 mA/cm~2 decreases from 5.5 to 4.1 V/mm first and then increases to 7.0 V/mm, the nonlinear coefficient increases from 2.39 to 2.62 first and then decreases to 2.42, and the apparent dielectric constant increases from 98 200 to 115 049 first and then decreases to 73 865 with the soaking time increasing from 0.5 to 5.0 h. These indicate that the optimal soaking time is 2.0-3.0 h considering both nonlinear electrical behavior and dielectric properties.