Selection of Zinc Coatings Based on Corrosion Behavior and Environmental Impact Assessment

This paper presents a novel and effective approach for the rational selection of zinc coatings in industrial applications. The corrosion behaviors of three types of zinc coatings were investigated through salt spray testing in the laboratory. Corrosion failure characteristics of the coatings were analyzed using corrosion morphology observation, electrochemical analysis, corrosion product identification, and weight loss measurements. Additionally, the environmental impacts of the production processes for the three coatings were evaluated. Among the three coatings, the thermally sprayed zinc–aluminum coating exhibited the best corrosion resistance in the salt spray test, while the hot-dip zinc coating showed the poorest performance. The electrochemical characteristics of the coatings at various stages of corrosion were examined using polarization curves, revealing the changes in corrosion current and corrosion potential that corresponded to the failure progression of the coatings. The corrosion products of the thermally sprayed zinc–aluminum coating primarily included ZnO, Al2O3, Zn(OH)2, and ZnAl2O4 phases. In contrast, the corrosion products of the thermally sprayed zinc coating and the hot-dip zinc coating predominantly consisted of ZnO and Zn(OH)2 phases. Finally, the environmental impact indicators of the three coatings were assessed using the IMPACT2002+ method.