Ultrahigh thermal conductivity fine-diamond/copper composites fabricated by pressure-assisted infiltration: process optimization

Fine-diamond/copper composites were prepared by pressure-assisted infiltration (PAI), and the infiltration temperature and time in the PAI process were optimized to get high thermal conductivity. Interface micro-structures, interface phase composition, wetting angle, and its effect on the thermal properties of the composites were investigated. The results show that the infiltration temperature and time are key parameters to get high thermal conductivity of the composites. Precise control of the infiltration temperature and time effectively regulated interfacial bonding and suppressed graphitization on the diamond surfaces, achieving high interfacial thermal conductance. The composites with 100 μm and 63 vol.% diamond particles infiltrated at 1150°C for 30 min under a pressure of 3 MPa exhibit thermal conductivity of 811 W·m⁻¹·K⁻¹, over 95% of the theoretical predictions by the differential effective medium (DEM) scheme. The high thermal conductivity is attributed to the favorable interfacial thermal conductance and nano-tungsten coating engineering.