Metal Injection Moulding Process for Copper / Diamond Composites with High Thermal Conductivity by Using Nanopowder

PM2010 Powder Metallurgy World Congress & Exhibition

ABSTRACT:This study aims to develop the MIM process for manufacturing the micro heat sinks made of copper/diamond composites with high thermal conductivity. Diamond powder was added into the feedstock composed of copper powder and polyathetal-based binder. The compound feedstock was moulded into a sacrificial plastic mould (SP-mould), and the green compacts with micro-pillars were obtained and the SP-mould was removed by means of solvent extraction. The green compacts were then oxidized in air, followed by sinteringin a reducing gas atmosphere. Nano-sized copper powder wasused for drastically decreasing the sintering temperatureto prevent from thermal damage on the surfaces of diamond particles. The sintered parts were also prepared by spark plasma sintering in contrast to conventional thermal furnace sintering, and they were evaluated by densityandthermal conductivitymeasurements. The experimental resultsshow thatusing nanopowder cangive sufficiently high sintered density at low sintering temperature.However, the thermal conductivity of sinterd parts cannot reach the high values to be expected from the rule of mixture.