Influence of soaking time on semi-conductivity and nonlinear electrical properties of TiO_2-based varistor ceramics

摘要

We investigated the influence of soaking time on the semi-conductivity and nonlinear electrical properties of TiO2-based varistor ceramic samples.We used a single sintering process and fabricated six disk samples of(Sr,Bi,Si,Ta)-doped TiO2-based varistor ceramics sintered at 1 250°C for 0.5 h,1.0 h,2.0 h,3.0 h,4.0 h,and 5.0 h,respectively.The samples were characterized by X-ray diffraction,breakdown voltage,and complex impedance.The results show that as the soaking time increases from 0.5 h to 5.0 h,the breakdown voltage drops before rising while the nonlinear coefficient increases and then decreases.We suggest that,considering both grain semi-conductivity and nonlinear electrical properties of the TiO2-based varistor ceramics,the optimal soaking time is between 2.0 h and 3.0 h.