Regulating interface adhesion and enhancing thermal conductivity of diamond/copper composites by ion beam bombardment and following surface metallization pretreatment

A new pretreatment process, namely, Ar+ ion beam bombardment and following deposition of a tungsten coating layer on diamond particles for fabricating diamond/copper composites is proposed in this paper. The composites are fabricated by infiltration method, and exhibited excellent thermal properties. Composition of the tungsten coated diamond particles is characterized by the Micro-XRD to investigate the effect of ion beam bombardment on the selectivity of interfacial reaction between the diamond planes and the coating layer. Scanning electron microscopy (SEM) is used to investigate the effect of the ion beam bombardment on interface structure and composition of the composites. A good interfacial adhesion without micro-gaps or cracks in the interfacial region is obtained. In addition to that, the phenomenon of selective interfacial reaction in the composite is no longer taking place, and the metal matrix uniformly adheres to all diamond planes. Therefore, the further enhancing thermal conductivity of the composites reach up to 896 W m−1 K−1, and coefficient of thermal expansion is only 5.9 × 10−6 K−1. The excellent performance can be attributed to the regulated interfacial adhesion and the optimized effective interfacial thermal conductance.