Preparation of the gradient Mo layers on diamond grits by spark plasma sintering and their effect on Fe-based matrix diamond composites

The functionally graded material in micro-scale, surface treatment of particles, was successfully prepared by spark plasma sintering. In this study, coating the diamond grit with gradient Mo layer was carried out by treating the mixture of diamond grits and molybdenum powders in the SPS system. A MoMo2C gradient coating with a thickness of 750 nm was prepared on the diamond grit at 870 °C for 60min. With the action of the gradient Mo layers, the compressive fracture strength and toughness impact of the diamond grits were improved by 20.7% and 5.9%, respectively. The gradient Mo layers improved the transverse rupture strength of Fe-based matrix diamond composites, and the interface combination strength between diamond grits and Fe-based matrix was increased by 349 MPa.