Preparation of thermally conductive and anti-corrosion coating by the insulation modification on graphite

Graphite (GR) is a commonly used two-dimensional filler with abundant sources and low cost. Its excellent electrical conductivity makes it widely used to prepare various conductive materials. However, its utilization in anti-corrosion materials is hindered by its extremely high conductivity, which pose significant challenges in material application. Nevertheless, its two-dimensional laminate structure serves as an effective filler for anticorrosion applications. If the insulation properties of graphite can be enhanced, it will significantly broaden its applications in anti-corrosion coatings. The hydrolysis and condensation of tetraethyl orthosilicate (TEOS) and gamma-methacryloxy propyl trimethoxy silane (MPS) were used to modify GR to improve its insulation. Additionally, this modification improved the compatibility between the filler and resin, reducing interfacial thermal resistance and thereby enhancing the thermal conductivity of the coating. The modified GR filler (SiO@GR) was added to epoxy resin (EPR) to prepare the composite coating (SiO@GR/EPR). When the SiO@GR content is 18 wt %, thermal conductivity can reach 0.67 W m- 1K- 1, and after soaking in 3.5 wt% NaCl solution for 7 days, the impedance modulus remains above 1.06 x 1011 Omega cm2. The synergistic effect of the physical barrier provided by two-dimensional fillers and the capacity enhancement of siloxane is thoroughly examined in relation to heat conduction and anticorrosive mechanisms. This study provides a simple approach to fabricating composite coatings with anti-corrosion and thermal conductivity performances.