This paper presents the development of a new hot water tank enamel designed for high durability in boiling water and alkaline environments. The enamel shows strong resistance to both water and alkali attack, tested under ISO 28706-1 (boiling water resistance) and SANS (alkali resistance using sodium bicarbonate) standards.
In the lab, several formulations were tested to improve long-term performance. Adjustments were made to the frit composition, mill additives, and water to solid ratio in the slurry to find the best-performing combination. The optimized enamel was applied on hot-rolled, enamel-grade steel in one side - one coat   application and fired at 860°C.
The paper also discusses key process parameters such as suspension properties and firing behavior, as well as common application defects and how to avoid them. To ensure suitability for domestic water contact, the enamel was tested against health-related migration limits using the UBA 85°C test method. The results confirmed that the enamel meets current regulations for food and drinking water contact.
Overall, this study offers new  durable porcelain enamel coatings for hot water tanks and similar systems, helping manufacturers achieve better corrosion resistance, longer service life, and compliance with safety standards along with enameling methods