T-ZnOw/硅橡胶复合材料的非线性电导特性研究

Investigation on the Nonlinear Conductance Characteristics of Silicone RubberComposites

针对目前许多绝缘装置存在的电场分布不均问题,采用具有自适应非线性电导特性的材料进行均压是一种有效手段。本工作使用具备独特三维结构的四针状氧化锌晶须(T-ZnOw)为无机填料对硅橡胶基体进行填充,制备了不同体积分数的T-ZnOw/硅橡胶复合材料,并对其电导特性、介电性能、拉伸强度进行了测试。研究结果表明:复合材料的逾渗阈值较低,仅为5%(体积分数);当T-ZnOw的体积分数低于5%时,复合材料不具备非线性电导特性;当T-ZnOw的体积分数大于5%时,复合材料具有良好的非线性电导特性;当达到临界场强E 0时,复合材料的电导率呈指数增加,且随着T-ZnOw体积分数的增加,复合材料的临界场强E 0值逐渐减小。此外,随着T-ZnOw体积分数的增加,复合材料的介电常数增大。加入适当体积分数的T-ZnOw填料有助于改善复合材料的拉伸强度。

In view of the uneven distribution of electric fields in many insulating devices,it is effective to make use of nonlinear conducting materials as field grading materials.In this work we employed T-ZnOw as inorganic fillers,and the silicone rubber as matrix.T-ZnOw/silicone rubber composites with different volume fractions were prepared,and their electrical conductivity,dielectric properties and stretching strength were measured.The results show that the percolation threshold of the composite is about 5vol%.Only when the volume fraction of T-ZnOw is above 5%,the composite materials can exhibit excellent nonlinear conductance characteristics.When a certain field strength value(critical field strength E 0)is reached,the electrical conductivity can be rapidly increased,which shows an apparent nonlinear conductivity.As the increase of volume fraction of T-ZnOw,the E 0 of the nonlinear electrical conductivity of the composite decreases correspondingly.The dielectric constants of the composite increase with the volume fraction of T-ZnOw.The tensile strength of the composite materials can be improved with an appropriate volume fraction.