Improvements in Mechanical Properties and Wear Resistance of Thermally Sprayed WC-Co Nanocomposite Coatings

Tungsten carbide WC-based composites are widely used in various wear applications requiring a combination of high toughness, high hardness, and good strength. Some researchers have demonstrated that WC-Co coatings with WC particles in the nanoscale range offer improved properties over their conventional counterparts. This work examines the performance of such conventional and nanostructured materials in the form of coatings deposited by high velocity oxy-fuel (HVOF) thermal spraying. The optimal deposition parameters of nanocomposite powders of WC-12%Co were previously determined. The performance of the coatings was examined under abrasion and sliding conditions. Improvements in mechanical properties and wear resistance were obtained from the nanocomposite coating and the results were attributed to more retained WC and consequently a lower amount of non-WC phases whose presence is detrimental to wear resistance. Also was found that the hardness and fracture toughness of the coatings depend on WC-binder adhesion and adhesion between splats.