E Nouri - Master Student
M Shahmiri - Assistant Professor
H.R Rezaie - Professor, Department of Materials and Metallurgical Engineering
F Talayian - Master Student, Department of Material Engineering, Sahand University of Technology, Tabriz

In this paper, zirconia -10 mol% alumina nanocomposite thin films produced by a sol-gel dip coating technique on the 316L stainless steel substrates were investigated at different temperatures. The results showed that this route led to the formation of a surface tetragonal zirconia (t-ZrO2) + corundum (α- Al2O3) phase free of cracks thin film with high crystallinity at 900 ºC. Electrochemical tests were carried out in NaCl 3.5% solution in heat treated samples. The experiments also showed most enhanced corrosion prevention in the samples due to these thin films at (600-700) ºC. Microstructures and phase changes of the synthesized thin films were characterized by thermogravimetric/ differential thermal analysis (TG/DTA), Fourier transform-infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM). AFM and SEM images showed that a uniform and free of cracks film on the surface is obtained in this process. Moreover, microstructural characterization by AFM analyses indicated that the average roughness at first decreases with increasing the temperature until 700 ºC and then increases. The SEM micrographs depicted that the morphology of the synthesized zirconia-10 mol% alumina nanocomposite thin films have changed according to the heat treatment history.

Zirconia-10 mol% alumina, nanocomposite thin films, sol-gel, heat treatment, 316Lstainless steel