The formation of atomic-level interfacial layer and its effect on thermal conductivity of W-coated diamond particles reinforced Al matrix composites

Abstract Diamond particles coated with a 45 nm-thick W layer were used to produce diamond particles reinforced Al matrix composites (Al/diamond(W)) by a gas pressure infiltration method. The results show that W atoms have diffused into Al matrix and replaced Al atoms during infiltration. As a result, a uniform 0.5 nm-thick Al 5 W interfacial layer is formed in the composite produced with 20 min infiltration time. The generation of the Al 5 W layer strengthens not only the interfacial bonding but also impedes the formation of hydrolysable Al 4 C 3 phase. With increasing infiltration time from 10 to 60 min, the thermal conductivity increases from 520 to 620 W/m K, which manifests the influence of interfacial layer thickness on thermal properties of the Al/diamond(W) composite. The study provides a new strategy to modifying the interfacial structure of Al/diamond composites on the aspects of both enhancing the thermal conductivity and preventing the formation of hydrolysable Al 4 C 3 phase.