DC current-voltage characteristic of silicon carbide/low density polyethylene composites

In order to investigate the non-linear conductivity characteristic of the silicon carbide (SiC)/low density polyethylene (LDPE) composites，combined with scanning electron 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 electric 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-crystal SiC are higher than those filled with α-crystal 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 37.5wt%，the increase of the size of SiC filler can cause the decrease of the critical electric field at which the relationship curve in loglog coordination presents the turn point.