The Effect of B Coating in Enhancing Properties of Al/Diamond Composites

Al/diamond composites are considered a new generation of potential thermal management materials. In this study, the uniform B coating on the surface of diamond particles was prepared by the vacuum thermal diffusion method. Subsequently, Al matrix composites reinforced with B-coated diamond particles were produced by the gas pressure infiltration method. The plating time was varied from 0 to 120 min to investigate the effect of B coating on the thermal conductivity and thermal expansion of the Al/B-diamond composites. The thermal conductivity for the Al/B-diamond composites increased from 422 W/m·K to 562 W/m·K with prolonged plating time from 0 to 90 min. Correspondingly, the coefficient of thermal expansion was tailored from 7.0 × 10^-6/K to 5.8 × 10^-6/K. The enhanced thermal conductivity and decreased coefficient of thermal expansion were attributed to strong interfacial bonding in Al/B-diamond composites. The results indicate that the appropriate thickness of B coating is a viable method to improve interfacial bonding between the Al matrix and B-coated diamond particles.