Effect of capacitance on ZnO-Bi_2O_3-Yb_2O_3 based varistor for nanosecond transients  

电容对毫微秒瞬变用ZnO-Bi_2O_3-Yb_2O_3基压敏电阻的影响（英文）

作　　者：Kannadasan RAJU Valsalal PRASAD 

机构地区：[1]Department of Electrical & Electronics Engineering, CEG Campus, Anna University

出　　处：《Journal of Central South University》2018年第10期2332-2338,共7页中南大学学报（英文版）

摘　　要：The microstructure and electrical properties of ZnO-Bi2O3-Yb2O3 based varistor ceramics were investigated with various temperature effects from 900°C to 1050°C.From the results,it was observed that the increase of sintering temperature offers a reduced capacitive effect from 0.460 nF to 0.321 nF.Furthermore,the grain sizes of varistors were varied from 6.8μm to 9.8μm.The consequence of such smaller grain sizes provided a better voltage gradient of about 895 V/mm for the disc sintered at 900°C and fallen drastically to 410 V/mm for the sample sintered at 1050°C.In addition,there was an increase of non-linearity index to a maximum value of 36.0 and reduced leakage current of 0.026 mA/cm2.However,the density of the varistor decreased with an increase of temperature from 5.41 g/cm3 to 5.24 g/cm3.With this base,the influence of varistor capacitance and high voltage gradient were scrutinized and it led an improved transition speed of the varistor assembly from non-conduction to conduction mode during intruding nanosecond transients.研究了ZnO-Bi_2O_3-Yb_2O_3基压敏陶瓷在900°C至1050°C温度范围内的显微组织和电学性能变化。结果表明,随着烧结温度的升高,电容效应从0.460 nF降低到0.321 nF。此外,压敏电阻的晶粒大小从6.8μm增大到9.8μm。这种小的晶粒使样品在900°C烧结时获得更好的电压梯度,约为895 V/mm,而当烧结温度升高到1050°C时,电压梯度迅速下降到410 V/mm。另外,非线性指数增加到最大值36.0,泄漏电流减少到0.026 mA/cm^2。然而,随着温度的升高,压敏电阻的密度从5.41 g/cm^3降低到5.24g/cm^3。在此基础上,考察了压敏电阻电容和高压梯度的影响,从而提高了压敏电阻组件在侵入纳秒瞬态下从非导电态转变到导电态的转变速度。

关 键 词：CAPACITANCE metal oxide varistor nanosecond transient rare earth oxide transition delay ytterbium oxide 

分 类 号：TM855[电气工程—高电压与绝缘技术]