In the current study, effects of sealing treatment by electroplating process on the corrosion and wear resistance of Ni-based NiCrBSi coatings deposited by flame spraying were investigated. Flame sprayed coatings produced had high porosity and low adhesion to substrate. Thus, these coatings were remelted by using oxyacetylene torch at 1100 °C. In order to seal flame sprayed NiCrBSi coatings, electroplating process in nickel chloride bath at 60 °C and pH=4 was performed. Microstructural characterization was carried out using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction pattern (XRD). The amount of porosity of these coatings were determined by image analyser software (Clemex). Also hardness test, wear test and corrosion test were carried out. Cyclic polarization test was done in order to investigation corrosion resistance of coatings. Wear test was carried out at two temperatures, 25 and 400 °C. Results showed that remelting process decreased the amounts of porosities and surface roughness, eliminated splat boundaries and improved metallurgical bonding between the coating and substrate. Microstructure of coatings consisted of solid solution Ni-rich matrix with Ni-Ni 3 B eutectic, hard boride and carbide precipitates. In the remelted coatings, microstructure was similar to the as-sprayed samples but with coarser precipitated particles. Results of X-ray diffraction patterns revealed some phases such as ?-Ni, Ni 3 B, CrB and Cr 7 C 3 in the as-sprayed and remelted coatings. Remelting process decreased the coating porosity and microhardness. Cyclic polarization results showed that by sealing the pitting corrosion resistance is increased. However no difference was observed between the wear resistance of sealed and unsealed coatings. It was also observed that the oxid layer is created on the surface during high temperature wear test. Keywords: Flame spray, NiCrBSi coating, microstructure, porosity, wear resistance, corrosion
