The effect of bonding method between WC-Cr3C2–Ni and multiwall carbon nanotubes powders on the properties of composite coatings

Abstract

The WC-20Cr3C2–7Ni/multiwall carbon nanotubes (WCN/MWCNTs) composite powders were prepared by mechanical bonding and surface modification, respectively. In the process of mechanical bonding method (M1), the dispersion of MWCNTs and maintained structural of composite powder (WCN1) were achieved by slurry-based dispersion. On the basis of the M1, a novel, simple and environment-friendly composite powder preparation method was proposed (M2). The surface of the composite powder (WCN2) was modified, leading to the transformation of interfacial bonding between WCN and MWCNTs from mechanical bonding to mechanical bonding accompanied by hydrogen bonding. The distribution of MWCNTs on the surface of WCN2 powder was more uniform than that of WCN1 power. The coatings (WCN, WCN1, WCN2) were prepared by high-velocity oxygen-fuel (HVOF) spraying. Compared with the WCN coating, the homogeneous distribution of MWCNTs not only increased the hardness, elastic modulus and corrosion resistance of the WCN2 coating, but also decreased the brittleness of the WCN2 coating.