Corrosion Behavior of Austenitic Steel 304 in Nearcritical Aqueous Solutions

摘要

In this paper, the corrosion characteristics of Austenitic steel 304 in nearcritical aqueous solutions containing 1000 ppm chlorides, and chemical oxygen demand (COD) of 2000 ppm, was investigated. The samples surface were examined using scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The results indicated that the most serious corrosion issues occurred at 360°C among three temperatures: 350°C, 360°C and 400°C. The water density and ion products play key roles in influencing the corrosion resistance of alloys under nearcritical aqueous solutions, while effects of temperatures on the stability of the scales are relatively minor. The corrosion resistance of 304 Steel in alkalescent solutions was better than that in other solutions. Generally, ～7.5 - 9 was an appropriate pH range.