The influence of deposition temperature on microstructure and corrosion resistance of ZrOxNy/ZrO2 coatings deposited using RF sputtering

This paper reports the influence of substrate temperature on the structure, morphology and corrosion resistance of ZrOxNy/ZrO2 thin films deposited on 304 stainless steel using radio frequency sputtering (RF sputtering). Structural analysis was carried out by X-ray diffraction (XRD); morphological analysis was performed using scanning electron microscopy (SEM) and atomic force microscopy (AFM) and surface chemical analysis was determined using X-ray photoelectron spectroscopy (XPS). XRD data showed that the films deposited at 300 °C (573 K) and 350 °C (623 K) result in the growth of a monoclinic zirconium oxynitride phase with preferential orientation along the (−1 1 1) plane, while at 14 °C (287 K) the predominant phase is of polycrystalline ZrO2. The corrosion results indicate that the coatings provide good resistance to corrosion in chloride-containing media, being better in the film deposited at 350 °C (623 K). SEM analysis demonstrated the homogeneity of the films deposited at the three temperatures; AFM studies established the average roughness of the films to be 4.25 nm. The binding energies of the Zr 3d, N 1s, and O 1s core levels determined by XPS were all compatible with the formation of a zirconium oxynitride and zirconium oxide in the surface of the film. ZrOxNy/ZrO2 thin films are promising candidates for increasing the corrosion resistance of the steels in chloride-rich environments.