Design of hBN/nano Al₂O₃ epoxy composites with enhanced thermally conductive and dielectric properties

The overall performance of 3D printed epoxy resin falls short of meeting the demands for the production and advancement of insulating components in electrified transportation equipment. This article introduces an approach for enhancing the dielectric characteristics of a composite epoxy resin oriented with hexagonal boron nitride by incorporating nano-alumina. Consequently, a 3D printed composite epoxy resin comprising nano-alumina and hexagonal boron nitride is successfully fabricated, demonstrating exceptional physical, chemical, and dielectric properties. The research findings unveil that, when the filler content reaches 3 wt% for nano-alumina and 27 wt% for hexagonal boron nitride, the micro-nano composite epoxy resin exhibits impressive mechanical characteristics while maintaining a significant degree of thermally conductive anisotropy. Specifically, at this precise filler content, the interlayer compatibility within the micro-nano composite epoxy resin experiences a substantial improvement, ultimately resulting in outstanding dielectric performance with a maximum volume resistivity of 5.5 × 10¹⁵ Ω∙cm and a surface resistivity of approximately 6.2 × 10¹⁴ Ω. Furthermore, the micro-nano composite epoxy resin, with in-plane-oriented hBN, exhibits the highest dielectric strength, achieving a peak value of 35.7 kV∙mm⁻¹ at the mentioned filler content. This investigation offers valuable insights into the development of high-performance 3D printed insulation components.