Microstructure and Oxidation Behavior of Carbide-Metal Cermet Material with Hybrid Binder

To address the limitations of cobalt-based cermet in oxidative and high-temperature environments, this study investigates a (W,Ti)C-based cermet system incorporating a hybrid binder composed of nickel (Ni) and 304 stainless steel (304ss). A series of cermets with varying Ni/304ss binder metal ratios were fabricated via vacuum sintering at 1440 °C. The introduction of 304ss into the Ni matrix enhanced interfacial diffusion and phase stability, effectively suppressing core–rim structures and promoting a uniform microstructure. Notably, the cermet with 8%Ni–8%304ss composition achieved a Vickers hardness of 15.6 GPa and fracture toughness of 9.21 MPa·m1/2, balancing mechanical strength and toughness. Isothermal oxidation testing at 450 °C showed that the hybrid binder substantially suppressed specific mass gain compared to monolithic Ni or 304ss systems. These improvements are attributed to the interplay between Ni-enhanced densification, which limits oxygen transport, and Cr-facilitated surface passivation, which stabilizes the oxide layer. The results highlight the potential of Ni-304ss hybrid binders as cobalt-free alternatives for high-performance tooling and wear-resistant applications in oxidative environments.