Enhancement of thermal conductivity in diamond/Al composites through vacuum-pressure thermal diffusion sintering

Improving the thermal conductivity (TC) of diamond–metal composites has always been a significant challenge in the field of thermal management. In this paper, diamond/Al composites are systematically studied, and the influence of the holding time (10–120 min) on interface structure and TC is discussed. The results of this research show that long-term thermal diffusion sintering can achieve dense interfacial bonding in diamond/Al composites, enhancing their TC. Diamond/Al composites with 50 vol% of 900 μm diamond attain the highest TC value of 888.73 W⋅m⁻¹⋅K⁻¹ under sintering conditions of 650 °C, 50 MPa, and 120 min — nearly 92% of the theoretical value predicted by the Maxwell model. This study establishes that high TC can be achieved through long-term thermal diffusion alone, without the need for complex diamond surface coating or substrate alloying.