Influence of chloride and bromide anions on localized corrosion of 15%Cr ferritic stainless steel

The influence of Cl− (919 ppm) and a mixture of Cl− (919 ppm) and Br− (51 ppm) on the corrosion behavior of 15%Cr ferritic stainless steel was investigated. Potentiodynamic and immersion tests were performed to examine the corrosion behavior. The size and the shape of pits were observed by optical microscope and scanning electron microscope. The oxide films formed on stainless steel were investigated by X-ray photoelectron spectroscopy (XPS). During the immersion test at 93 °C for 600 h, Fe and Cr were mostly corroded to iron and chromium oxides. The results of depth profiling indicate higher corrosion rate of solution containing chloride than the mixture solution. It was clear that the addition of Br− to the solution containing Cl− inhibited the localized corrosion of 15%Cr ferritic stainless steel.