High-Temperature Oxidation Behavior of Solution Precursor Plasma Sprayed Nanoceria Coating on Martensitic Steels

Solution precursor plasma spray (SPPS) is used to deposit nanoceria coating on a 410 martensitic stainless steel. The process of pyrolysis in converting the cerium nitrate solution to cerium oxide, the microstructure and the surface chemistry is confirmed by thermodynamic calculations, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction. Subsequent exposure of the coated steel in atmospheric air to cyclic oxidation at 1000 degrees C revealed excellent corrosion resistance of the steel in presence of the SPPS-processed nanoceria coating. The formation of the nanostructured (10-100 nm) ceria coating is studied using transmission electron microscopy. Relative Ce4+ and Ce3+ concentration in the coating was determined from XPS high-resolution spectrum. Cross-section scanning electron microscopy showed the presence of an impervious nature of the protective layer with reduced scale thickness in the coated-oxidized sample. After a pre-oxidation treatment at 1273 K of the coated specimen, the oxidation kinetics showed a significant decrease as compared with the uncoated martensitic steel.