Wear behavior of HVOF sprayed cobalt-based composite coatings reinforced with Cr3C2

Metal matrix composites are widely used to improve the wear resistance of materials, and, among these composites, WC-Co and Cr3C2-NiCr (metallic binders) are the most common systems used for thermally sprayed applications. On the other hand, metallic coatings such as cobalt-based alloys are also used for high temperature and wear resistant applications. Among the cobalt-based alloys, Stellite-6 shows a transition from severe to mild wear at high temperatures due to a formation of an oxide layer on the surface. However, the reinforcement of cobalt-based alloys (such as Stellite-6) with Cr3C2 particles has not been widely explored. In this research, coatings of Stellite-6 reinforced with Cr3C2 were deposited on steel substrate by high velocity oxygen fuel (HVOF) technology. The tribological behavior of the composite coatings was evaluated at room temperature and 300 °C using reciprocating dry sliding wear tests. A comparative study of microstructure and chemical composition using scanning electron microscopy (SEM) and Raman spectroscopy, as well as wear and hardness testing, were performed to evaluate the effect of carbide content on the tribological behavior of coatings. Based on these results, the wear mechanisms of the coatings are proposed, focusing on the influence of the reinforcement to improve the wear performance of the coatings.