General Corrosion Behaviors of Austenitic Stainless Steels in Zinc Containing PWR Primary Water

General corrosion of 304 and 316L stainless steels was studied in simulated pressurized water reactor (PWR) primary water environment containing 10 μg/kg zinc. After exposion for 1 000 h, the oxide films formed on the surface of specimens were analyzed by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results showed that the corrosion weight gain of 304 stainless steel was higher than that of 316L, and the oxide film on 304 was looser than that on 316L. The oxide film was a double layer structure, in which the outer layer was thin and rich in Fe and Zn, while the inner layer was rich in Cr. The chemical composition analysis showed that the outer layer was mainly made up of (Zn,Fe,Ni)(Fe,Cr)2O4, the inner layer was ZnCr2O4, and the transition layer between oxide film and matrix metal was mainly Cr2O3.