LAUSR

ABSTRACT The life of a machine part limited by high wear rate can be prolonged by HVOF thermal spray coatings followed by laser treatment. The main hindrance of the HVOF spraying is the porosity of the coatings, which can disturb its performance in particularly erosion/corrosion environments. In the present paper, three coating materials have been arranged. Tungsten carbide cobalt (WC-12Co) of both conventional micro-sized Diamalloy 2004 and superfine nanostructured InfralloyTM S7412, mixed with Inconel 625 (Ni-Cr alloy) Diamalloy 1005, were used to produce hard coatings applied by HVOF thermally sprayed process onto carbon steel 4041 substrates. The substrates were laser treated by changing laser power and scanning speed. The present work investigates the effect of laser power and scan speed on the melt profile and microhardness on the laser-treated HVOF thermally sprayed coatings. This study of laser treatment and melt profile gives physical insight into the process and provides useful information on the effect of laser power and scan speed. Laser treatment of thermally sprayed coatings could considerably improve the hardness of the laser-treated zone and minimise the porosity of coatings.