Effect of cobalt content and nickel interlayer on the bonding strength and properties of LCS\WC–Co via PM technique

Abstract The fabrication of cost-effective LCS\WC–Co layered composites with high mechanical reliability remains a significant challenge. In this study, bilayer composites were fabricated by powder metallurgy at a compaction pressure of 313 MPa and a sintering temperature of 1300 °C, and the effect of a Ni interlayer combined with varying Co contents was systematically investigated. Microstructural analyses showed that the LCS\Ni\WC–Co composites exhibited defect-free interfaces with minimal porosity and relative densities exceeding 93.2%, indicating strong metallurgical bonding. XRD results revealed that the Ni interlayer effectively suppressed the formation of the brittle η-phase (Fe 3 W 3 C) compared with directly bonded LCS\WC–Co composites by modifying interfacial diffusion and promoting the formation of (Ni,Co)-based solid solutions. Consequently, the Ni-containing composites exhibited improved wear resistance and lower coefficients of friction. Among the investigated compositions, LCS\Ni\WC–12Co achieved the highest performance, with a bonding strength of 240 MPa, fracture toughness of 28 MPa m 1/2 , hardness of 700 HV, and a coefficient of friction of 0.38. These findings demonstrate that Ni interlayer engineering effectively enhances interfacial stability, suppresses detrimental phase formation, and promotes a favorable balance between hardness, toughness, and tribological performance.