Electrical and Mechanical Properties of SiR/Nano-silica/Micro-SiC Composites

SiR/nano-silica/micro-SiC composites were prepared in order to develop high voltage direct current (HVDC) insulation materials, and their HVDC insulating breakdown strength and tensile strength were carried out. Nano-silica content was fixed to 20 wt% and micro-SiC content varied from 0 to 30 wt%, and the micro-SiC was pretreated with hexamethyldisilazane before use. Positive HVDC insulation breakdown strength for SiR/nano-silica (20 wt%)/micro-SiC (10 wt%) composite was 72.08 kV/mm which was 18.2% higher than that of SiR/nano-silica (20 wt%) nanocomposite without SiC (60.99 kV/mm), which meant that properly dispersed micro-SiC enhanced the insulation breakdown strength. The maximum tensile strength was also shown in the SiR composites with nano-silica (20 wt%)/micro-SiC (10 wt%).