Corrosion characteristics of Ti and Al2O3/Ti thin films sputtered on 316LSS

In this work, two thin films (Ti and Al2O3/Ti) were deposited on 316LSS substrates by the physical vapor deposition (PVD) sputtering technique. Heat treatment was applied for thin films at 400 degrees C for 2 h. Thin films were divided into two groups, The First group cooled in the air (normalized), and the second cooled in the furnace (annealed). The electrochemical characteristics were investigated by potentiodynamic polarization (POT) and impedance spectroscopy (EIS) tests. The corrosion resistance (CRST) for all thin films before and after heat treatment was determined in 3.5% NaCl at room temperature (RT). Scanning electron microscope (SEM), and surface topography were studied for all thin films before and after heat treatment and corrosion tests. At asdeposited conditions, superior CRST belonged to Ti thin film. Meanwhile, after heat treatment, the annealed 316LSS/ Al2O3/Ti had the lowest corrosion rate 0.17 mm/y, and the highest CRST of about 3655 ohm.cm2.