Thermal spraying of nanostructured cermet coatings

A nanostructured WC–12Co powder was sprayed using three different HVOF gun-fuel combinations in which the fuels were kerosene, hydrogen and propylene. Using particle diagnostics, significant differences were observed in the particle temperatures and velocities generated using these various combinations. Important differences were identified when comparing various aspects of coatings produced using either hydrogen or propylene as the fuel. When using hydrogen, deposition efficiencies were higher, the coatings were harder and the extent of carbide degradation was less than when propylene was employed as the fuel.