Low-temperature synthesizing SiC on diamond surface and its improving effects on thermal conductivity and stability of diamond/Al composites

SiC is an ideal interface layer between diamond and matrix because it possesses high thermal conductivity and good interfacial matching with diamond. In this paper, a novel approach of synthesizing SiC on diamond surface at low temperature was proposed, and then the SiC-coated diamond particles were used as reinforcement to fabricate diamond/Al composites by a vacuum pressure infiltration method. The results showed that the synthesizing temperature of SiC could be as low as 750 °C. Al4C3 was the indispensable intermediate phase for synthesizing SiC at low temperature. Furthermore, the SiC coating layer was beneficial to enhance the thermal conductivity and stability of diamond/Al composites. Thermal conductivity of the composites increased from 590 to 666 W⋅m−1⋅K−1 with a 12.9% increase after diamond surface was covered by the SiC interface layer. It’s worth noting that the SiC-coated diamond/Al composites exhibited good long-term stability of thermal conductivity in a wet environment. The decreasing percentage of thermal conductivity was only 6.31% for the SiC-coated diamond/Al composites, which was much lower than that of the raw diamond/Al composites (22.54%) after 500 h soaking water treatment.