中文摘要：

为探讨碳化硅（SiC）／低密度聚乙烯（LDPE）复合材料的电导非线性特性，结合扫描电镜观察和X射线衍射分析研究了SiC的掺量、种类、晶型及粒径对SiC／LDPE复合材料直流伏安特性的影响。研究结果表明：SiC掺量增加可导致SiC／LDPE复合材料电导率增大和电导非线性系数发生改变的临界场强值降低；当外施电场强度相等时，在相同的SiC掺量下，纳米α-SiC、绿β—SiC、黑α—SiC复合材料的电导率分别大于微米α—SiC、绿α-SiC、绿α-SiC复合材料的电导率，且前者的电导非线性特性明显优于后者；当黑α—SiC的掺量达到37．5wt％时，SiC粒径的增大可导致双对数坐标下的电导率与场强关系曲线的拐点向低场强方向移动。

英文摘要：

In order to investigate the non-linear conductivity characteristic of the silicon carbide （SiC）/low density polyethylene （LDPE） composites, eombined with scanning eleetron microscopic observation and X-ray diffraction, the DC current- voltage characteristic of LDPE/SiC composites with different types, contents, crystal forms and sizes of SiC was studied. The experimental results show that the increase of the SiC content will cause the increase of the conductivity of SiC/LDPE composite and the decrease of the critical eleetrie field under which the nonlinearity coefficient of conductivity changed; under the same electric field and with the same content of SiC, the conductivities of the composites filled with β-erystal SiC are higher than those filled with α-erystal SiC for nano-meter SiC, green and black SiC, and the nonlinearities of the composites filled with β- crystal SiC are stronger; when the filling content of the black α-crystal SiC up to 37.5 wt%, the increase of the size of SiC filler can cause the decrease of the critieal eleetric field at which the relationship curve in loglog coordination presents the turn point.