Effect of carbide interface layer construction on the interface structure and thermal conductivity of diamond/copper composites

The intrinsic mismatch between copper and diamond creates a trade-off between interfacial bonding and heat transfer in diamond/Cu composites, limiting their thermal potential. In this study, tungsten (W) and chromium (Cr) coatings were deposited on the surface of diamond particles via magnetron sputtering and electroless plating, respectively. Subsequently, W@diamond/Cu and Cr@diamond/Cu composites (with a diamond content of 33 vol.%) were fabricated by Spark Plasma Sintering (SPS). The thermal conductivity of the two composites and the temperature gain were tested, and the influence mechanisms of the thermal conductivity and temperature gain performance were finally explored. The results show that both coatings form continuous, uniformly distributed carbide layers (W₂C, Cr₃C₂, Cr₂₃C₆) at the interface. The thermal conductivity of the W@diamond/Cu composite reaches 720 W m⁻¹ K⁻¹, which is higher than that of the Cr@diamond/Cu composite (679 W m⁻¹ K⁻¹). In the temperature gain test, the W@diamond/Cu composite exhibits a lower steady-state temperature and higher cooling efficiency. Microstructural analysis reveals that the W₂C layer maintains a semi-coherent orientation relationship with diamond, while the chromium carbides are incoherent. This interfacial crystallographic difference fundamentally governs the thermal performance disparity. Through the interface engineering strategy, this study achieves an effective and synergistic optimization of the interfacial bonding and heat transfer performance of diamond/Cu composites. It provides experimental evidence and theoretical references for the design and preparation of high-performance thermal management materials.