Synthesis and characterization of zirconium oxynitride ZrOxNy coatings deposited via unbalanced DC magnetron sputtering

• ZrO0.8N0.2 coatings were deposited by DC sputtering using air as the reactive gas.
• The ZrO0.8N0.2 films grew in the cubic phase and preferentially oriented in plane (222).
• A thin film of ZrO2 (c) promotes the growth of ZrO0.8N0.2.
• The coating of ZrO2/ZrO0.8N0.2 increases the corrosion resistance of steel.

A study of structure, morphology, and corrosion resistance was performed on zirconium oxynitride thin films deposited on 304 and 316 stainless steels by the DC sputtering magnetron unbalance technique. Structural analysis was carried out using X-ray diffraction (XRD), while morphological analysis was performed by scanning electron microscopy (SEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM). These studies were performed as a function of deposition time via DC sputtering at room temperature (287 K) with an Ar/air flow ratio of 3.0 and a total deposition time of 30 min. The oxynitride films were grown with cubic crystalline structures Zr2ON2 and preferentially oriented along the (222) plane. Chemical analysis determined that in the last 5.0 nm, the Zr coatings present the following spectral lines: Zr3d3/2 (184.6 eV) and 3d5/2 (181.7 eV), O1s (531.3 eV), and N1s (398.5 eV).The zirconium oxynitride films enhance the stainless steel's resistance to corrosion. The protective efficacy has been evaluated using electrochemical techniques based on linear polarizations (LP). The results indicate that the layer provides good resistance to corrosion in chloride-containing media. SEM analysis presented the homogeneity of the films. AFM studies indicated that the average roughness of the film is 20.2 nm in the two steels and a particle size ranging between 150 and 208 nm in ZrOxNy-AISI 316 and 115–180 in ZrOxNy-AISI 316. TEM analysis indicated columnar growth.