探究两步烧结工艺下微米级粉料的氧化锌电阻片的微观结构及电性能

Microstructure and Electrical Properties of Two-Step Sintered ZnO Varistors with Micron-Sized Powders

笔者以微米级粉体为原料,采用两步烧结法制备氧化锌电阻片,系统地研究了各烧结条件下氧化锌电阻片的微观结构,致密化程度,基本电性能和介电性能,包括阻抗谱和介电损耗谱。结果表明,两步烧结能有效地减小晶粒尺寸,使晶粒分布均匀,增强致密化。在合适的两步烧结曲线下,其样品的电压梯度为402.26 V/mm,漏电流为0.98μA/cm2,非线性系数为60.88。两步烧结样品在低温下介电损耗的两个驰豫峰对应的活化能为0.22~0.24 eV和0.34~0.37 eV,传统烧结样品对应的活化能为0.24 eV和0.32 eV,二者均认为分别由电阻片内部的本征缺陷,锌间隙和氧空位引起的。

Zn O varistors were prepared by two-step sintering method using micron-sized powders. The microstructures,densification,basic electrical properties and dielectric properties,including impedance spectrum and dielectric loss spectrum,of ZnO varistors under various sintering conditions have been systematically studied. The results show that the two-step sintering can effectively reduce the grain size,make the grain distribution uniform and enhance densification. Under a suitable two-step sintering curve,the voltage gradient of the sample is 402. 26 V/mm,the leakage current is 0. 98 μA/cm2 and the nonlinear coefficient is 60. 88. The activation energies corresponding to two relaxation peaks of the dielectric loss of two-step sintered samples at low temperature are 0. 22-0. 24 eV and 0. 34-0. 37 eV. The activation energies corresponding to the traditional sintered samples are 0. 24 eV and 0. 32 eV. Both are considered to be caused by the intrinsic defects inside the varistor,zinc interstitial and oxygen vacancy.