Effect of interface structure on thermal conductivity and stability of diamond/aluminum composites

Diamond/aluminum composites were fabricated by gas pressure infiltration with pure aluminum and pristine diamond, nanoscale W or WC coated diamond as raw materials. The influence of interfacial phase type and size on the thermal conductivity of the composites was investigated. The evolution of microstructure and properties of composites under temperature shock environment was also analyzed. The introduction of W and WC coatings inhibits the formation of interfacial phase Al4C3, while the generation of amorphous carbon in WC-coated diamond/aluminum composite causes a weak interface bonding and huge acoustic impedance difference with diamond, leading to a decrease in thermal conductivity. The W-coated diamond/aluminum composite shows the optimal thermal properties after 1000 cycles of temperature shock treatment. The introduction of W coating can improve performance stability while maintaining high thermal conductivity, making them promising thermal management composites.