Applied Surface Science, Vol.477, 166-171, 2019
Thermal stability, wettability and corrosion resistance of sputtered ceria films on 316 stainless steel
In this study, ceria films were prepared on 316 stainless steel (SS) substrates by magnetron sputtering technique. Thermal stability of ceria films was evaluated by annealing as-deposited films at temperatures between 400 degrees C and 1000 degrees C for 1 h in ambient air. Surface morphology, microstructure, wettability and chemical composition were studied by atomic force microscope (AFM), scanning electron microscope (SEM), X-ray diffraction (XRD), contact angle goniometer and X-ray photoelectron spectroscopy (XPS), respectively. In addition, corrosion behaviors of ceria films were investigated by potentiodynamic polarization tests in 3.5 wt.% NaCl solution. The results revealed the good thermal stability of sputtered ceria films, the morphological, structural and wetting properties can be sustained under the temperature up to 700 degrees C. Water contact angle measurements showed that the film surfaces became hydrophilic immediately after annealing, but the hydrophobic character was recovered after exposure in ambient air. From the polarization test results, ceria films improved the corrosion resistance of steel substrates significantly and the lowest corrosion current density (similar to 23.81 nA/cm(2)) was obtained for the sample annealed at 400 degrees C, which was one order of magnitude lower than that of bare 316 SS. (c) 2017 Elsevier B.V. All rights reserved.
Keywords:Ceria films;Thermal stability;Wettability;Microstructure;Corrosion resistance;Magnetron sputtering