Bond strength and wear performance of plasma sprayed and arc sprayed Ni-Cr-Al coatings

Morphology, bond strength, residual stress and wear resistance of plasma sprayed and arc sprayed Ni-Cr-Al coatings were investigated by means of SEM, fensile test, Almen method and wearing tests. The relationships between the coating thickness and bonding strength and deflection of the Alwen strips were examined.Both coatings exhibit typical characteristic layered structure with good bonding interface. The bond strength and deflection of the coated samples decrease with the increase of coating thickness. When the thickness of coating is greater than 0.5 mm,the decline range of bonding strength and deflection of plasma-sprayed coating is higher than that of arc-sprayed coating with the increase of thickness. The bonding strength of plasma-sprayed coating is 21.57 MPa and deflection is 10.9 × 10^-3 in(l in=25.4 mm) with the max thickness of 1.3 mm. For the arc-sprayed coating, the bonding strength is 22.79 MPa and deflection is 10.9 × 10^-3 in when the coating thickness is 2.2 mm. Weight loss increases with the increasing of wearing time and load while the relative weight loss decreases when the wearing time increases.