Atmospheric plasma sprayed Cu coating on Cu–B/diamond composite for electronic packaging application

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Although Cu/diamond composites have high thermal conductivity, the limited processibility and weldability of the hard and inert diamond reinforcement limit their applications for electronic packaging. Therefore, there is a necessity for surface metallization of the Cu/diamond composites. Here, a Cu coating with a thickness of 170 μm is sprayed onto a Cu–B/diamond composite using a rapid deposition technique of atmospheric plasma spraying. The adhesion strength between the Cu coating and the composite is measured to be 13.1 MPa. The Cu-coated composite demonstrated a significantly enhanced wettability, as evidenced by the reduction of the contact angle between the solder and the Cu–B/diamond composite from 96° to 10°. Surface roughness and composition determine the wettability between the solder and the substrate. However, the thermal conductivity of the Cu–B/diamond composite is somewhat decreased from 839 to 738 W/mK after depositing the Cu coating, which is ascribed to the low thermal conductivity of Cu coating. The findings provide an effective way for metalizing Cu/diamond composites for the integration of electronic devices in thermal management.