Plasma modification promotes self-alignment of SiC particles for enhanced nonlinear conductivity of epoxy composites

Electric field-assisted fabrication technology can enhance the nonlinear conductivity of composites along the alignment direction by driving the self-assembly of fillers. However, it is difficult to form a significant filler orientation network at low filler loading, resulting in limited improvement in nonlinear conductive performance. In this work, SiC treated by dielectric barrier discharge (DBD) is utilized as the filler, and the influence of the DBD treated SiC (TSiC) on the construction of the oriented network is investigated by characterizing the dielectric constant, x-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy (FTIR). Then, the TSiC/epoxy composite is prepared with assisted electric field application, and the DC conductivity, as well as partial discharge characteristics, is measured. The results show that the -OH group can be introduced on the SiC surface by DBD treatment, thereby enhancing the dipole polarization of particles under the assisted electric field. Therefore, the TSiC can be driven more easily by the assisted electric field, promoting the formation of particle chains at a lower filler loading. Moreover, the nonlinear conductive performance of the prepared sample can be enhanced along the direction of the particle chains with a significant reduction in the nonlinear threshold, effectively suppressing the partial discharge at DC voltage.