Mechanical and tribological properties of (Ti,Zr,Nb,Mo) (C,N)/(Ti,Zr,Nb) (C,N) composite ceramics via spark plasma sintering

To address the insufficient strength, toughness, and wear resistance of conventional Ti(C,N) ceramics, novel (Ti,Zr,Nb,Mo) (C,N)/(Ti,Zr,Nb) (C,N) composite ceramics were prepared via spark plasma sintering (SPS). Systematic friction and wear experiments, combined with multiscale microscopic characterization, were conducted to elucidate the friction-reducing and anti-wear mechanisms of the as-prepared materials. The results demonstrate that the design of the novel composite ceramics enables synergistic improvements in both mechanical and tribological properties. Through the Zener pinning effect and subsequent fine-grain strengthening, the (Ti,Zr,Nb) (C,N) second phase effectively refines the grains and enhances the mechanical performance of the composite ceramics. Under identical testing conditions, the composite ceramics exhibit lower friction coefficients and wear rates than their conventional counterparts. During sliding, the residual compressive stress within the second phase raises the critical load for plastic deformation and improves fracture resistance, thereby inhibiting crack initiation and propagation. In addition, a stable surface oxide film acts as a barrier that prevents direct contact between the ceramic counterbody and the Ti(C,N) composite. This barrier effect, together with the grain boundary pinning effect and the wear-resistant framework, contributes to a marked improvement in both wear resistance and friction reduction.