Comprehending the role of the S-phase on the corrosion behavior of austenitic stainless steel exposed to H2S/CO2-saturated liquid and vapor environments. (28th May 2021)

• Record Type: Journal Article
• Authors: Li, Longyi; Yan, Jing; Wang, Feng; Qin, Bingchao; Chen, Guang; Tang, Zhenghua; Zhang, Hongtao; Liao, Li; Wang, Jun
• Is Part Of: International journal of hydrogen energy. Volume 46:Number 37(2021)
• Page Start: 19508
• Page End: 19522
• Publication Date: 2021-05-28
• Subjects: H2S/CO2 corrosion -- S-phase -- Austenitic stainless steel -- XPS; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2021.03.078
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: The corrosion behavior of austenitic stainless steel after low-temperature liquid oxy-nitriding (LON) was investigated by exposing in H2 S/CO2 -saturated liquid and vapor environments up to 720 h at 60 °C. The corrosion rates before and after LON were compared by the weightlessness method, and the microstructure as well as the corrosion scales were characterized using surface analysis methods. The results indicated that the composite S-phase layer with the outer Fe3 O4 layer and the inner nitrogen-rich sublayer could improve the corrosion performance in H2 S/CO2 -saturated environment. The base material (BM) suffered local corrosion first, which then transformed into uniform corrosion. As a comparison, The LON sample, covered with a thin corrosion product layer, indicated slight local corrosion. The excellent corrosion resistance of the S-phase should be attributed to the blocking effect of the continuous Fe3 O4 film as well as the suppression of the atomic mobility by the nitrogen-containing supersaturated solid solution. Highlights: The difference in the corrosion behavior of austenitic stainless steel in the vapor and liquid phases is analyzed. In the H2 S/CO2 -saturated liquid/vapor phase, the corrosion rate of the LON sample is 93.1% lower than that of the BM. The nitrogen atoms in the S-phase can increase the local pH value and accelerate the passivation in acidic environments. The continuous Fe3 O4 layer can effectively block offensive ions. Supersaturated nitrogen could suppress the atomic mobility thereby reducing the dissolution of metal atoms.