Simulating sulfuric acid dew point corrosion of enamels with different contents of silica

Corrosion of three bulk enamels with different silica contents in sulfuric acid was studied. Catastrophic corrosion happened for enamel with 54.6 wt% silica. Its weight loss reached 36.90 mg/cm2 after seven-day corrosion. A porous leached layer with tremendous cracks formed at surface during corrosion, which favored acid invading and further corrosion. On the contrary, the durability of enamels with silica content over 60 wt% was guaranteed by their highly connected silicate network and a developed dense gel layer that clogged corrosion pits. Their weight losses were less than 0.2 mg/cm2 after seven-day corrosion.