The Korean Society of Surface Science and Engineering

The global transition toward decarbonization has accelerated renewable-energy adoption, increasing operational variability in thermal power plants and driving a greater demand for flexible operation. Under such conditions, flue-gas temperatures frequently fall below the sulfuric-acid dew point, accelerating dew-point corrosion and shortening component life. This study systematically evaluated ceramic and perfluoroalkoxy alkane (PFA) coatings deposited on S-Ten2 and enamel-steel substrates under simulated dew-point-corrosion conditions. We characterized surface morphology, microindentation hardness, electrochemical behavior, and microscratch resistance. Compared with PFA, ceramic coatings exhibited higher hardness, superior interfacial adhesion, and improved electrochemical stability. Ceramic-coated S-Ten2 delivered the highest overall performance, likely associated with stable interfacial oxides from alloying elements (Cr, Ti) that enhance coating adhesion. In contrast, PFA showed lower hardness, pronounced load-induced creep, and severe delamination in scratch tests, particularly on enamel-steel. Collectively, the data indicate that ceramic coatings on S-Ten2 are a promising approach for mitigating dew-point corrosion in air-preheater applications, with the potential to extend component lifetime and reduce maintenance in flexible power-plant operations.

Keywords Dew-Point Corrosion, Flexible Operation, S-Ten2 Steel, Ceramic Coating, PFA Coating