Improvement of the corrosion characteristics of 1.4713 ferritic steel in 0.1 M sulfuric acid by heat treatment and Al2O3-TiO2 coating

Abstract

This study addresses the influence of heat treatment and alumina coating on the corrosion of EN 1.4713 steel in 0.1 mol dm(-3) sulfuric acid. The corrosion characteristics of three different samples are examined using the open circuit potential measurements, Tafel extrapolation, linear polarization resistance, weight-loss method, and electrochemical impedance spectroscopy. The results showed that the application of the weight-loss method yielded similar values to the electrochemical method in the first 24 h. A decrease in corrosion rate, in a similar manner, was observed for all three samples. The largest deacceleration was obtained for the alumina/titania-coated sample. It was obtained that the heat treatment significantly increased the corrosion resistance, but only in the first 24 h. The alumina/titania coating decreases the corrosion rate by approximately 30 times at the beginning of the corrosion exposure and by nearly 300 times after 240 h. This coating could have a significant influence on construction design, which uses ferritic stainless steel as the material.