Investigation on the Corrosion Behavior of the Bilayered Ceramic Coatings Deposited Using Atmospheric Plasma Spraying

Atmospheric plasma spraying (APS) was employed to deposit Al2O3, ZrO2, Al2O3/ZrO2and ZrO2/Al2O3 coatings on the stainless steel substrate. Microstructural analysis of the as-sprayed coatings was carried out using scanning electron microscope (SEM). Elemental analysis of the coatings was performed using Energy-dispersive X-ray Spectroscopy (EDS) attached with SEM. The corrosion behaviors of the coatings were performed using both the potentiostat and salt spray test in 5 wt% NaCl solution. The results show that the bilayered ZrO2/Al2O3 coating possesses improved corrosion resistance when compared to the other three coatings.