High corona‐resistant and low‐dielectric nanoepoxy resin composites

To address the issue that the insulation systems of inverter‐fed motors and transformers suffer from rapid degradation or even failure due to corona discharge under high‐frequency pulses and high‐temperature conditions, this paper aims to develop a composite material with both low dielectric properties and excellent corona resistance. In this study, SBRNO composite oxides were synthesized via hydrothermal synthesis and surface modification using phenyltriethoxysilane, tributyl borate, zirconium n ‐propoxide, and zinc oxide as raw materials. SBRNEP nanocomposites with different filler loadings were then prepared by ultrasonic dispersion and thermal crosslinking. The effects of SBRNO on the dielectric properties and corona resistance of epoxy resin were systematically investigated. The results show that the optimal performance was achieved at a doping content of 10 wt%. At 50 Hz, the corona‐resistant lifetime was increased by approximately 980%, and at 10 kHz, by about 780%. Meanwhile, the dielectric constant was reduced to 2.50 and the dielectric loss was controlled below 0.010, which are significantly superior to those of conventional epoxy resin materials.