Influence of Hydrogen Sulfide on the Corrosion-Electrochemical Properties of 20 Steel with Coatings Based on Zinc and Aluminum

We study the corrosion of a hot-dip zinc coating and arc-sprayed aluminum and zinc coatings in chloride- acetate solutions and model seawater saturated with hydrogen sulfide. It is shown that, in chloride–acetate solutions, hydrogen sulfide promotes an increase in the corrosion rate of 20 steel by more than an order of magnitude. For the hot-dip zinc coatings, hydrogen sulfide does not change the corrosion rate, whereas for the arc-sprayed coatings, it decreases the corrosion rate by a factor of ∼ 5. The saturation of model seawater with hydrogen sulfide decreases the corrosion rate of 20 steel by a factor of ∼ 7 and the corrosion rate of the hot-dip zinc coating by a factor of ∼ 1.4 but does not affect the corrosion rate of the arc-sprayed coating. The insoluble corrosion product of zinc, namely, its sulfide, does not passivate these coatings. Hydrogen sulfide leads to an insignificant increase in the corrosion rate of the arc-sprayed aluminum coating both in a chloride–acetate solution and in model seawater. Its values are 3–7 times lower than for 20 steel, which indicates the possibility of application of the coatings based on aluminum for the corrosion protection of steels in hydrogen-sulfide-containing media.