Improvements of dielectric and space charge accumulation in epoxy resin nanocomposites by magnetic field directional distribution of boron nitride nanosheets using γ-Fe₂O₃ surface modification

Space charge accumulation at the electrode/insulation interface indicates a significant challenge to composite insulation in high-power electric and electronic devices. The present study implements an external magnetic field to fabricate the non-uniform distribution of γ-Fe₂O₃@BNNS (boron nitride nanosheets) nanoparticles at the electrode/epoxy nanocomposite interface. The pulsed electro-acoustic method (PEA) technique was utilized to evaluate the space charge accumulation under DC and square-wave voltages. Furthermore, the dielectric and trap parameters of the nanocomposites were explored by wide-band dielectric spectrum and thermally stimulated current (TSC) technique, respectively. The findings indicate that the incorporation of γ-Fe₂O₃@BNNS markedly diminished both the average charge density and the maximum electric field. The modified γ-Fe₂O₃@BNNS effectively mitigated space charge accumulation at the electrode/sample interface under square-wave voltages. Specifically, the 0.5 wt% modified γ-Fe₂O₃@BNNS yields a 53 % decrease in charge accumulation at a frequency of 500 Hz. While, the 0.1 wt% sample demonstrates a 30 % reduction in electric field distortion compared to the neat epoxy at 500 Hz. Hetero-charge accumulation is detected in epoxy nanocomposites. The modified γ-Fe₂O₃@BNNS fillers at interface introduced additional deep traps, contributing to reduction in charge injection and increase in charge recombination. Consequently, it improves the space charge characteristics of epoxy resin composites for high-power electrical and electronic applications.