Effect of Nano-SiC coating on the thermal properties and microstructure of diamond/Al composites

A 20 nm SiC nanocoating was prepared on the surface of crushed diamond particles using a combination of sol -gel and in situ reaction methods. 50 vol% SiC-coated diamond particles reinforced 6061Al composites were fabricated by vacuum hot pressing method. Part of the SiC, with a crystallographic orientation relationship of (-11-1)Diamond//(-11-1)SiC and [-110]Diamond//[-110]SiC between SiC and diamond, remains at the interface, which reduces the mismatch of phonon vibration modes between the diamond and Al matrix. Thus, the inter-facial thermal conductance of the composite was greatly improved compared to that of composite prepared by diamond without coating. The thermal conductivity of the composite is 485 W/mK, which is the highest among the crushed diamond/Al composites and similar to that composite fabricated by single-crystal diamond. It is significant for the industrial application of diamond/Al composites that obtain a composite with well machin-ability and TC using the crushed diamond with nano-SiC coating.