Sliding wear behaviour of laser clad coatings based upon a nickel-based self-fluxing alloy co-deposited with conventional and nanostructured tungsten carbide-cobalt hardmetals

Nickel-based self-fluxing alloys (SFA) have been widely used as coatings in the light of their high levels of wear and corrosion resistance. However, their resistance to wear can be substantially improved by reinforcement with tungsten carbide-cobalt hardmetals. In this work, a range of coatings based on a nickel-based self-fluxing alloy has been produced by laser cladding. The coatings have been reinforced with both conventional and nanostructured WC-Co at a single level of 30 wt.%. The effect of ceria as a grain refiner has also been examined. The sliding wear behaviour of the coatings was examined in a block on ring apparatus and the temperature of the samples measured during the wear tests. In all cases, the addition of WC-Co to the base alloy resulted in a significant increase in wear resistance, with wear rates of the reinforced deposits being less than 10% of that of the unreinforced deposit. The coating reinforced with a mixture of conventional and nanostructured WC-Co exhibited the lowest rates of wear. The addition of ceria was shown to significantly refine the microstructure of the deposit; however, little change was observed in the wear behaviour of the resulting material.