Structure-property optimization in Fe-based diamond composites through biomimetic “brick-mud” interface mediated by Mo-B-C coating

Fe-based diamond -composites exhibit considerable potential for applications owing to their excellent mechanical and wear properties. However, the weak interfacial bonding between the Fe-based matrix and diamond particles has consistently limited their overall performance, adversely affecting the working efficiency of diamond tools. In this study, a Mo-B-C coating was pre-coated on the diamond surface. During the sintering process, the in-situ gradient chemical reaction between Fe and Mo-B-C coating resulted in the formation of a biomimetic ‘brick-mud’ interfacial structure consisting of Mo 2 FeB 2 , Mo 2 BC, and amorphous carbon layers. The “brick-mud” structure, combining soft and hard phases, enhanced the interfacial toughness by effectively deflecting, branching, and prolonging interfacial cracks. Additionally, the transitional diffusion of Fe within the interface layer helpd alleviate the interfacial stress concentration and suppress diamond graphitization. As a result, the optimization of interface bonding contributed to a 26.1 % increase in bending strength and a 156 % enhancement in abrasive ratio of the Fe-based diamond composites, offering a novel strategy for interfacial modification in Fe-based diamond tools.