纳米SiC/低密度聚乙烯复合材料的空间电荷与电导特性

利用熔融共混法制得不同纳米SiC质量分数（0.5%、2.0%、3.0%）的纳米SiC/低密度聚乙烯（LDPE）复合材料，研究了添加纳米SiC颗粒对LDPE介电性能的影响。利用SEM观测了纳米SiC颗粒的分散特性，利用电声脉冲（PEA）法测得40 kV/mm场强作用下纳米SiC/LDPE复合材料的空间电荷分布特性。利用热刺激电流（TSC）进一步验证纳米SiC添加能够提高LDPE的陷阱浓度。结果表明:纳米SiC颗粒能够均匀地分散在LDPE中，未出现较大的团聚现象。纳米SiC质量分数为0.5%、2.0%和3.0%的纳米SiC/LDPE复合材料空间电荷注入量明显低于LDPE。短路600 s后的残留空间电荷密度远小于LDPE。纳米SiC/LDPE复合材料的空间电荷注入量与电导率均随着纳米SiC的增加而减少。纳米SiC质量分数为3.0%的纳米SiC/LDPE复合材料场强非线性系数为2.6，远小于LDPE的4.3。TSC曲线表明纳米SiC/LDPE复合材料内部制造了大量的陷阱，抑制了载流子在材料内部的输运，从而阻碍了空间电荷的迁移和积聚。 

Space charge and conductive characteristics of nano-SiC/low density polythylene composites

Nano-SiC/low density polyethylene (LDPE)composites with different nano SiC mass fractions (0.5%, 2.0%,3.0%)were prepared by melt blending method.Effects of nano-SiC particles on dielectric properties of LDPE were studied.Dispersion character of nano-SiC particles was observed by SEM.Space charge distribution character of nano-SiC/LDPE composites under 40 kV/mm field strength was obtained by using pulse electro-acousitc (PEA)method.Thermal simulated current (TSC)was also employed to further identify that nano-SiC can increase the trap density of LDPE.The results show that nano-SiC particles disperse uniformly in LDPE and there is no lar-ger agglomeration.The quantity of inj ected space charge of nano-SiC/LDPE composites with nano SiC mass fraction of 0.5%,2.0% and 3.0% are much lower than that of LDPE.After short circuit 600 s,the residual space charge density is much smaller than that of LDPE.The quantity of inj ected space charge and conductivity of nano-SiC/LDPE composites both reduce with the increase of nano-SiC particles.The nonlinear coefficient of electric field of nano-SiC/LDPE composites with nano SiC mass fraction of 3.0% is 2.6,which is much smaller than that of LDPE of 4.3.TSC curves show that a large number of traps appear in nano-SiC/LDPE composites,which inhibit the transportation of carriers in material,thus hinder the migration and accumulation of space charge.