Effect of Mo2B5 coating on diamond graphitization and cutting performance of Fe-based diamond composites

The bottleneck of iron-based diamond composites lies in the fact that iron is highly susceptible to catalyzing diamond graphitization, which leads to premature diamond detachment, thus affecting work efficiency. In this paper, a transition metal boride (Mo₂B₅) is coated on the diamond surface. During the sintering process of the composites, the Mo₂B₅ coating and Fe undergo a series of chemical reactions to build up an interfacial layer for inhibiting diamond graphitization. The wear performance of the Fe-based matrix diamond composites was examined by wear tests with grinding wheels. The results show that introducing the interfacial layer greatly reduces the degree of interfacial amorphous carbon by isolating the direct contact between the diamond and the Fe-based matrix. The decrease in the degree of interface graphitization promotes the interfacial bonding of diamond with the matrix, resulting in a 59 % increase in the abrasive ratio of the composites. This study introduces a novel coating and method for interfacial modification of metal matrix diamond composites, and the mechanism of its influence on the amorphous carbon content of the interface and wear performance of the composites is thoroughly investigated.