Study on the Microstructures and Corrosion Behavior of Plasma Sprayed Dicalcium Silicate Coatings

In this study, dicalcium silicate (Ca₂SiO₄) coatings were deposited on stainless steel substrates by atmospheric plasma spraying. Salt spray and immersion tests were carried out to evaluate corrosion performance and XRD, SEM, and EDS were used to analyze phase composition and microstructure. During corrosion testing, calcium carbonate crystals appeared on coating surfaces and the pores were filled with hydration products, producing denser coatings. Potentiodynamic polarization curves and electrochemical impedance spectroscopy plots indicated that the corrosion resistance of the coatings increased after immersion in saltwater and artificial seawater, and in the latter case, a silica-rich layer was observed between the coating and the calcium carbonate crystals.