Effects of the ambient oxygen concentration on WC-12Co cermet coatings fabricated by laser cladding

[Display omitted] •Effects of oxygen concentration during the laser cladding of WC-Co were investigated.•WC-Co clad beads with few pores were obtained under the optimum conditions.•Reduced oxygen concentration and laser power effectively prevented pores.•The temperature measurement made it possible to predict the pore frequency. Surface coatings of tungsten carbide-cobalt (WC-Co) cermet materials on mechanical components are useful for wear-resistant applications. Laser cladding has recently been widely adopted as a surface modification process offering advantages over other conventional techniques. Thus far, however, the laser cladding of WC-Co cermet coatings has been compromised by the appearance of abundant defects (pores and cracks). In this study we investigated the effect of the ambient oxygen concentration on the laser cladding of WC-Co within an oxygen-control chamber designed for laser cladding. From our results, balancing of a lower oxygen concentration and an optimum heat input was effective in preventing the pores and the decarburization caused by the reaction of carbon and oxygen during the laser cladding.