WC Reinforced Surface Metal Matrix Composite Produced By Plasma Melt Injection

Technologies for producing surface metal matrix composites have the virtual of coating and composites, and can be used to produce composites with metallurgical bonding to the substrate and good wear-resistance with low cost, according to different requirements of the parts.Plasma melt injection was used to produce WC-17Co reinforced surface metal matrix composite on Q235 substrate in this thesis. The plasma melt injection process was analyzed theoretically. The microstructure and composition were tested with SEM, TEM, XRD and EDS. Wear-resistance of the composite and the substrate were tested. The results showed that, with plasma melt injection, good WC-17Co reinforced surface metal matrix composite could be produced on Q235 substrate. The main factors affected the process included size of the particle, injection speed, melting and cooling conditions, density of the particle and the liquid metal, and wettability of the particle. There were many phases in the composite, like Fe₃W₃C, Co₃W₃C, WC, γ -Fe, Co₃O₄, γ-Co, FeW₃C, Fe₂W, W₂C and so on. The reinforced phases were distributed uniformly. Pre-heating slowed down the cooling rate of the melt pool, and increased the tendency of falling down of WC. The friction coefficient of the surface metal matrix composite was far lower than that of the substrate, and the wear-resistance of it was increased greatly.