Effect of Bond Coat Diffusion on Adhesion Behaviour of Hard Alloy Powder NiCrBCSi (Fe) Coatings Thermally Sprayed on 60CrMn4 Steel

The object of the present work is to study the spraying of poly-powders nickel bases containing Cr, Si, C and B elements addition with variable percentage of iron, deposited on a steel substrate by oxy fuel thermal spraying. The substrate surface was previously treated by Al–Ni bond coat and post–annealing at 650°C. The spraying powder and coating micro structure were investigated by combination of X-ray diffraction, electron microprobe and scanning electron microscope coupled to an analyzer energy dispersive x-ray. The adherence to substrate was determined by using shear test for adhesion. The result of this study was to investigate to compare potentials of HVOF sprayed NiCrBCSi and satellite 6 coating for a possible to replacement of hard chromium plating. A good adherence of coating NiCrBCSi (Fe) on steel substrate is explained by formation of large diffusion zone in interface after annealing and by the nature of the structure deposit duplexes.