High Velocity Spray Deposition of WC Cermets by an Air-Oxygen Controlled Combustion Process

An air-oxygen controlled high velocity combustion spraying process has been developed that uses a special HVOF gun and a broad range of fuel-oxidant ratios. Extremely low flame temperatures can be achieved while maintaining a supersonic flow of combustion products, thus allowing the solid state deposition of almost all industrially relevant alloys. This work deals with the development of superhard cermet coatings using conventional and fine WC-Co(Cr) powders, optimized spray parameters, and different nozzle geometries. Results are compared based on coating microhardness, toughness, and sliding wear resistance.