The influence of soaking time on the nonlinear electrical behavior and dielectric properties of TiO2-based varistor ceramics was investigated. Based on single sintering process, six disk samples of （Sr, Bi, Si, Ta）-...The influence of soaking time on the nonlinear electrical behavior and dielectric properties of TiO2-based varistor ceramics was investigated. Based on single sintering process, six disk samples of （Sr, Bi, Si, Ta）-doped TiO2-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/cma 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 1l5 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.展开更多
In order to investigate the influence of sintering temperature on the Schottky barrier and bulk electron traps of ZnO varis- tors, ZnO-Bi2O3 based varistor ceramic samples were sintered at 1000, 1100, 1200 and 1300℃,...In order to investigate the influence of sintering temperature on the Schottky barrier and bulk electron traps of ZnO varis- tors, ZnO-Bi2O3 based varistor ceramic samples were sintered at 1000, 1100, 1200 and 1300℃, respectively. The measured results indicate that the sample sintered at 1300℃ possesses the lowest voltage gradient and nonlinear coefficient, compared with other samples. The barrier height of the samples decreased as the sintering temperature increased, which resulted in the deterioration of nonlinearity. Furthermore, two bulk electron traps determined by admittance spectroscopy were generally independent of sintering temperature, which indicated that these two traps might originate from the intrinsic defects in ZnO lattice.展开更多
基金Project(50872001) supported by the National Natural Science Foundation of ChinaProjects(KJ2007B132, KJ2009A006Z) supported by the Scientific Research Foundation of Education Department of Anhui Province, ChinaProject(XJ200907) supported by the Foundation of Construction of Quality Project of Anhui University, China
文摘The influence of soaking time on the nonlinear electrical behavior and dielectric properties of TiO2-based varistor ceramics was investigated. Based on single sintering process, six disk samples of （Sr, Bi, Si, Ta）-doped TiO2-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/cma 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 1l5 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.
基金supported by the National Natural Science Foundations of China(Grant Nos.50425721 and 50737001)
文摘In order to investigate the influence of sintering temperature on the Schottky barrier and bulk electron traps of ZnO varis- tors, ZnO-Bi2O3 based varistor ceramic samples were sintered at 1000, 1100, 1200 and 1300℃, respectively. The measured results indicate that the sample sintered at 1300℃ possesses the lowest voltage gradient and nonlinear coefficient, compared with other samples. The barrier height of the samples decreased as the sintering temperature increased, which resulted in the deterioration of nonlinearity. Furthermore, two bulk electron traps determined by admittance spectroscopy were generally independent of sintering temperature, which indicated that these two traps might originate from the intrinsic defects in ZnO lattice.
