Effect of inhibitors on the electrochemical corrosion of heat-resistant ceramic coatings deposited on non-alloy steel

• A.V. Efimov, E.V. Kharanzhevskiy, S.M. Reshetnikov, T.A. Pisarevа and M.G. Gotsuk

Udmurt State University, ul. Universitetskaya, 1, 426034 Izhevsk, Russian Federation

Abstract: The corrosion resistance and electrochemical behavior of heat-resistant metal-matrix composites (MMCs) obtained by high-speed laser synthesis and deposited on the surface of non-alloy steel have been studied. It has been shown that the corrosion resistance of the coatings thus obtained can be improved by applying some corrosion inhibitors prior to coating. Four variants of the original powder mixture were studied, which were subjected to high-speed pulsed laser irradiation after applying on the surface of non-alloy steel. The original powder mixture contained various concentrations of finely dispersed zirconium dioxide, boron carbide, silicon carbide, and boron nitride combined with nickel powder. Depending on the concentration of these components, an MMC layer up to 20 μm thick was produced in the course of laser treatment. The coatings thus obtained have high strength and wear resistance, low friction coefficient, and high level of adhesion to the substrate. The phase composition of the coatings was studied by X-ray single crystal analysis. The corrosion resistance and electrochemical behavior of samples were studied by anodic polarization under potentiodynamic conditions in a neutral buffer solution. It has been shown that the corrosion resistance of some samples should be enhanced. The effect of various inhibitors preliminarily deposited on the surface of samples on their corrosion resistance and electrochemical behavior was studied. The results of this study reveal a special effect of various inhibitors, which is related with the specific features of the coating composition, structure, and characteristics. The following inhibitors exhibited high efficiency: benzotriazole (BTA), potassium dichromate, and perhydropolysilazane. The technique of impregnating samples with solutions of the above inhibitors was used. Perhydropolysilazane was applied on sample surfaces with a brush.

Keywords: ceramic coating, boron and silicon carbides, boron nitride, zirconium borides, zirconium oxides, inhibitor treatment

Int. J. Corros. Scale Inhib., 2021, 10, no. 2, 838-850
doi: 10.17675/2305-6894-2021-10-2-22

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