Protective conversion coatings based on rare-earth compounds for passivation of galvanized steel

Abstract

The publication deals with the development of a process for applying protective conversion coatings containing rare earth metals (REMs) on the surface of galvanized steel to replace environmentally hazardous chromating processes. The compositions of solutions for the deposition of individual protective/decorative or adhesive coatings have been optimized, and the physicochemical and mechanical properties of coatings that might be potential alternatives to toxic chromate coatings have been studied. The addition of rare-earth metal (REM) compounds and citric acid to the solutions increases the protective ability, abrasion resistance, frost and heat resistance of the coatings being formed, and improves the appearance and thickness uniformity.