Effect of laser melting on plasma sprayed WC-12Â wt.%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 130 mm standoff distance. The coated samples were melted using a CO2 laser with an inert gas shroud. Four different laser speeds from 100 mm/min to 250 mm/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.