Effect of laser melting on plasma sprayed WC-12wt.%Co coatings

Tungsten carbide powder with 12% Co was deposited on AISI 321 stainless steel substrate by air plasma spraying. The coating was produced at 130mm standoff distance. The coated samples were melted using a CO2 laser with an inert gas shroud. Four different laser speeds from 100mm/min to 250mm/min were used to melt the coatings. After laser melting the treated surfaces were characterized and compared with as sprayed surfaces. It was observed that the laser melting process produced defect free surfaces. The results showed that the thicknesses of the melted surfaces and wear resistance varied as a function of laser speed. •The surface of WC-12%Co cermet sprayed by APS technique has been modified by using CO2-laser.•All the inherent coating defects have been vanished and good surface properties were achieved during modification.•New phases were observed after the re-melting of surfaces which are discussed in detail.