Mo2C interface layer: effect on the interface strength and cutting performance of diamond/Fe-Ni-WC composites

The weak interfacial strength between Fe-based matrix and diamonds causes diamond particles to fall off prematurely, significantly affecting the cutting efficiency of diamond composites. This work aimed to optimize the interfacial microstructure and mechanical properties of the diamond/Fe-Ni-WC composites by coating a Mo 2 C layer on the diamond particles. The Mo 2 C-coated diamonds were prepared via the molten salt method. Diamond/Fe-Ni-WC composites were sintered by the hot-pressing process under a vacuum. The bending strength of composites with Mo 2 C-coated diamonds was improved from 804 to 996 MPa with the increased coating time. The energy dispersive spectroscopy scanning indicated that the Mo 2 C coating layer changed the interfacial composition between the matrix and the diamonds from Fe–C alloy to Mo 2 C, improving the interface strength. Moreover, the diamond protrusion heights of composites were raised by adding a Mo 2 C interface, resulting in an improvement in the cutting efficiency of impregnated diamond tools.