Effects of different element coatings on the interface characteristics and thermal conductivity of vacuum-sintered diamond/Cu composites

The interface structure holds paramount significance in enhancing the thermal conductivity (TC) of diamond/Cu composites, positioning them as a promising candidate for thermal management applications. Diamond/Cu composites (55% volume fraction) with three distinct interfacial carbides were fabricated via sintering at 950 °C using Cu and diamond powder coated with Ti, Cr, and W. During the sintering process, interfacial layers of TiC, Cr3C2, and W2C carbides formed at the composite interfaces. The findings reveal that the interfacial bonding strength among these three composites adheres to the following hierarchy: Ti-D/Cu exceeds Cr-D/Cu, which surpasses W-D/Cu. This hierarchy stems from the varying degrees of carbide coating integrity attained at 950 °C. Furthermore, the coating morphology differs on the diamond-{100} and -{111} crystal planes. Notably, among the interfacial carbides, TiC coating exhibits the most compact and contiguous structure postsintering. Consequently, Ti-D/Cu composites boast the highest density, reaching 95.49%, along with a remarkable TC of 317.66 W/mK. A comparative analysis of the fracture morphology of these composites reveals that Ti-D/Cu, characterized by the most robust interfacial bonding, exhibits a intransgranular fracture mechanism. This study offers profound insights and theoretical implications for the interface design of diamond/Cu composites, paving the way for their effective utilization in heat dissipation materials.