Enhanced irradiation resistance and thermal conductivity of SiC induced by the addition of carbon under Au²⁺ ion irradiation

A significant decrease in the thermal conductivity of SiC after irradiation has hindered its practical applications. To solve this problem, polymer-derived pure SiC and C-SiC composites were irradiated under 4 MeV Au²⁺ ions, and their thermal conductivity was evaluated. The time-domain thermoreflectance method was found to be effective and sensitive to obtain the thermal conductivity of the irradiated layer. In pure SiC, irradiation-induced complete amorphous SiC significantly decreased the thermal conductivity. However, in C-SiC composites, the heterogeneous interface between C and SiC probably increased the irradiation resistance, leaving residual crystallinity in both C and SiC phases and resulting in a higher thermal conductivity. The thermal conductivity of C-SiC composites was dominated by SiC matrix. The optimal thermal conductivity of SiC related composites after irradiation can be designed by controlling the distribution, size, content, interface, and degree of crystallinity of the two phases in the future.