Thermal Conductivity of Silicone Rubber Composites: Effects of Ceramic Fillers, Pressure, and Temperature

This study investigates the influence of ceramic fillers—aluminum oxide (Al₂O₃), boron nitride (BN), and a combination of aluminum oxide and zinc oxide (ZnO)—with different particle sizes, on the thermal conductivity of solid silicone rubber. Additionally, the impact of potential synergistic interactions from the simultaneous addition of selected fillers is explored to identify pathways for enhancing thermal conductivity. Replacing 10 vol% of Al₂O₃ with hexagonal BN (h-BN) in a silicone rubber composite containing 50 vol% Al₂O₃ increases thermal conductivity by 32%, from 1.56 to 2.07 W m−1 K−1. Furthermore, the thermal conductivity of the silicone compounds is examined under various pressure and temperature conditions to better understand its behavior under realistic application conditions. The results reveal that the influence of pressure and temperature on thermal conductivity is linear within pressure ranges from 10 to 200 bar and temperatures from 30 to 200 °C.