Effects of Crystallization on the Corrosion Resistance of Arc-Sprayed FeBSiNb Coatings

FeBSiNb coatings with a primarily glassy structure were prepared by arc spray processing. The as-sprayed coating was devitrified at various annealing temperatures to form different portions of crystalline phase. The effect of crystallization on the corrosion resistance of the coatings was systematically studied by potentiodynamic polarization and electrochemical impedance spectroscopy analysis in 3.5 wt.% NaCl solution. The results indicate that the as-sprayed coatings exhibit a superior corrosion resistance to the crystallized coatings with high polarization resistance, and the corrosion resistance of the coating deteriorates with the increase in the amount of crystalline phase. The corrosion resistance of both as-sprayed and devitrified coatings is explained in terms of chemical and structural characteristics of the alloys.