Enhanced thermal conductivity of diamond/copper composite fabricated through doping with rare-earth oxide Sc2O3

Diamond/copper composite has been considered as one of the next generation thermal management materials. Interfacial modification is an essential means of ameliorating interface wettability and bonding of diamond/copper composite for improving its thermal conductivity. In the present work, Diamond/copper composite was manufactured by using spark plasma sintering (SPS) technology with 60% volume fraction of diamond mixed with 40% volume fraction of copper power, chromium powder (0.7 wt%) and scandium oxide powder (0.21 wt%). A series of material analysis methods were used to characterize the microstructure, interfacial layer, phase compositions and distributions of Diamond/copper composite. The total and partial electron density of states (DOS) for Diamond-Cr-Sc2O3 interfacial model was investigated by means of first-principles calculations from CASTEP modules. The results showed Sc2O3 made a 5–20 nm well-arranged and uniformly distributed interfacial chromium carbide layer in the interface region, which played a critical role in increasing the amount of reactive interfacial bonding and decreasing defect. The addition of Sc2O3 brought the increasing number of heat transfer carriers at the interface and made the interface energy system more stable. The obtained diamond/copper composite exhibited that the wettability between diamond particles and copper was effectively improved. The thermal conductivity of diamond/copper is 872 W/(m·K) and the possible reasons for doping rare-earths Sc2O3 to improve the thermal conductivity were discussed.