Shape, microstructure and properties of diamond/copper composites prepared by binder jet additive manufacturing

In this work, in order to achieve the net near forming of diamond/copper composites, the binder jet 3D printing (BJ3DP) was employed to prepare and the printing parameters and sintering temperature were optimized. Subsequently, in order to further improve the relative density and thermal conductivity of the printed parts, tungsten metallization of diamond was carried out and its effects on the interfacial bonding between diamond and copper were discussed. The experimental results showed that the green parts with best quality was obtained when the print layer thickness and binder saturation were 100 μm and 50 %, respectively. After sintering at 1250 °C, the diamond/copper composites prepared by BJ3DP achieved the highest relative density of 92.16 % along with the most excellent heat dissipation performance, in detail, a thermal conductivity of 229 W·m⁻¹·K⁻¹. After tungsten plating on the diamond surface, the relative density and thermal conductivity of the samples were improved and reached to 94.95 % and 343 W·m⁻¹·K⁻¹, respectively. This may be attributed to that the interfacial bonding between diamond and copper was enhanced by formation of WC and W₂C phase during sintering. This work provides a process basis and data reference for the preparation of diamond/copper composites by BJ3DP.