A Comparative study for wear resistant of Stellite 6 coatings on nickel alloy substrate produced by laser cladding, HVOF and plasma spraying techniques

Stellite 6 coatings were deposited using laser cladding, high velocity oxygen fuel (HVOF) thermal spraying and plasma spraying techniques on a nickel alloy substrate. The surface roughness, chemical composition and microstructure of these coatings were characterised by a surface profilometer, optical microscopy (OM) and scanning electron microscopy (SEM). The microhardness of the coatings was measured and the wear behaviour of the coatings was examined under controlled test conditions in a pin-on-plate (reciprocating) tribometer. The results showed that fully dense and crack-free laser clad Stellite 6 coatings can be formed on a high nickel steel substrate. Average microhardness values of the matrix for the coatings were in the range 350-520 HV and the pin-on-plate (reciprocating) wear tests showed the laser cladding coating performed the highest wear resistance compared to the other two coatings.