Effect Of Electric Field Induced Technology On Dielectric Properties Of SiC/Polyethylene Composites

The nonlinear resistive field grading composite is able to homogenize electric field distribution and to suppress space charge.Generally,a proper amount of nonlinear filler is filled in the polymer matrix to prepare resistive field grading composites,but the filler loading is usually very high,leading to the preparing difficulty and mechanical properties of the composite.The existing research results show that electric field induction technology can make resistive field grading composites have nonlinear conductivity characteristics at low filler loading,but the related influencing factors are still unclear.Therefore,it is necessary to study the influence of electric field-induced factors on the nonlinear conductivity of composites.Firstly,Si C/PE composites were prepared based on electric field induction technology.The distribution of Si C particles in PE matrix after electric field induction was observed by scanning electron microscope.At the same time,the effects of electric field induced amplitude,filler loading and hot-pressing temperature on the dielectric properties,conductivity properties and surface potential properties of the composites were studied.For the composites prepared under DC induced electric field,the fillers are arranged in gradient structure in the matrix.The increase of DC induced electric field amplitude and the hot-pressing temperature is beneficial to the orientation of Si C particles,which increases the relative dielectric constant,nonlinear coefficient and surface potential decay rate of the composite.With the increase of Si C content,the relative dielectric constant,current density and nonlinear coefficient of the composites increase,and the surface potential attenuation rate increases.For the composites prepared under AC induced electric field,the fillers are arranged in chain structure in the matrix gradually.With the increase of AC induced electric field amplitude,filler loading and hot-pressing temperature,the relative dielectric constant,current density and nonlinear coefficient of the composites increase,and the surface potential decay rate presents an increasing trend.Compared with the 40wt% composites without induced amplitude,the composites with 20wt%and 30wt% filler content have higher nonlinear coefficients under AC induced electric field of 1k V/mm,indicating that electric field induction technology can make the composites have better nonlinear conductivity characteristics at a lower filler loading.