Structural and electrochemical characterization of ZrO2?Al2O3 un?stabilized nanocomposite thin films as a function of Al2O3 content on the 316L SS substrate

Zirconia?alumina (ZrO2?Al2O3) nanocomposite thin films containing 0?50 mol% alumina (Al2O3) were deposited on 316L stainless steel (316L SS) substrates by a sol?gel dipping route. In this research, we used zirconium acetate hydroxide and aluminum isopropoxide as ZrO2 and Al2O3 precursors, respectively. The effect of Al2O3 content on the structural evolution of the nanocomposite was investigated using thermogravimetric/ differential thermal analysis (TG/DTA) and X?ray diffractometry (XRD). The results confirmed the crystallization of tetragonal (t?ZrO2) and monoclinic (m?ZrO2) as zirconia phases and corundum (α?Al2O3) as an alumina phase in ZrO2?m mol % Al2O3 (m = 20?50) films. Furthermore, the increase in Al2O3 content was accompanied by disappearing of the t?ZrO2 phase. Scanning electron microscopy (SEM) images showed that the morphology and phase distribution in the films also depend upon the Al2O3 content. Influence of Al2O3 on corrosion resistance of coated 316L SS substrate were examined by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in 1?M H2SO4 solution at 80 °C. The results demonstrated ZmA nanocomposite thin films improved anti?corrosion behaviour of substrates.