Study of forming process and corrosion kinetics of non-nickel single-layer glass enamels

This work presents the results of researches of a new kind of non-nickel low-melting enamels for flexible direct-on enameling technology of steel pipes, working in corrosion-active medium. Starting glasses for enamel coatings belong to the system SiO₂-RO₂-B₂O₃-Al₂O₃-RO-R₂O. Based on the requirements of competitiveness we have developed the new composition of special complex adherence promoter, containing different transition metal oxides such as cobalt and copper that facilitate adhesion to steel. The coating forming mechanism on steel substrate and the role of CoO and CuO oxides were explained. The relationship of the corrosion activity of melted glass frits and the coating adhesion at glass/steel interface is investigated. The results of measuring adherence strength and chemical durability of single-layer enamels are provided. The corrosion kinetics of glass enamels was examined by the statistical analysis method. Competitive fluorine- and nickel-free one-coat protective enamels meet the requirements of standards for enameled steel pipes. (author)