LASER CLADDING OF NICKEL BASED POWDERS

Nowadays, the laser cladding process is used for improving or reconditioning ferrous and non-ferrous surfaces. The variety of alloyed powders that can be used for achieving high density laser cladded layers with enhanced corrosion and wear resistances represents one of the main advantages of this coating process. The good bonding with the substrate make this process suitable for a wide variety of industrial applications where high hardness and low cracking susceptibility of coatings are mandatory.

This paper addresses to the laser cladding of Ni based powders on a low carbon steel substrate using a TRUMPH pulsed laser and a PRECITEC YC50 coaxial cladding head. Cracks free cladded layers are obtained by optimising the main process parameters: laser power and cladding speed. The geometrical profile of the coatings is investigated as well as the dilution percent with the base materials. Optical and SEM microscopy reveals the formation of large dendritic structures near at the coating-substrate interface and the formation of complex carbides and borides in a nickel based matrix. The mechanical behaviour of the cladding layer is analysed by micro-hardness testing.