Chemical Resistance of Vitreous Enameled Cast Iron

This study investigates the chemical resistance of vitreous enamel coatings applied to cast iron substrates under water environments. Two SiO2-Na2O-B2O3-CaO-Al2O3-based frits (ground G1 and G2) were developed to investigate the influence of chemical composition, heat-treatment temperature, and titanium glaze top-layer application on elemental release behaviour. The coatings were heat-treated at different temperatures (740 ◦C and 780 ◦C). They were subjected to distilled water leaching tests to assess their durability through inductively coupled plasma (ICP). The results show that the G2 coating exhibited significantly lower elemental release compared to G1 due to the incorporation of Li2O and TiO2. Furthermore, the heat-treatment temperature had no prominent influence on the performance of G2. For G1 and G2, the application of a glaze top layer effectively reduced the release of hazardous elements such as Co, Mn, and Cr. However, incomplete surface coverage of the glaze top-layer left localized areas susceptible to leaching and resulted in localized attack. In summary, compositional optimization and glaze top-layer proved to be the most effective approach for enhancing the chemical resistance of vitreous enamel coatings on cast iron.