Date:

2025-04-30

Title of Paper:

Early Corrosion Characterization of 316 Stainless Steel (Passivated in Supercritical Water with Na3PO4) in Subcritical Water Containing Oxygen and NaCl

Journal:

Journal of Materials Engineering and Performance

Summary:

Corrosion has severely hindered the development and application of high-temperature hydrothermal
oxidation technologies for disposing of chloride-containing organic wastewater. This study explored the
early corrosion behaviors of 316 stainless steel (316 SS) (UNS S31600), passivated by sodium phosphate
(Na3PO4) in supercritical water in advance, in subcritical water (at 100, 160, 230, and 300 C and 25 MPa)
having high contents of oxygen (O2) and sodium chloride (NaCl) for 50 h. The results show that the
corrosion rate of the phosphate-passivated 316 SS was approximately half of that of the passivated 316 SS
(pretreated in supercritical water without Na3PO4) under the same conditions. The surface oxides of the
phosphate-passivated 316 SS consisted of Cr2O3, Fe2O3, CrPO4, FePO4, and Ni3(PO4)2. The passivation
pretreatment of 316 SS in supercritical water with Na3PO4 could form a stable and protective oxide film
containing phosphates. These phosphates significantly improved the corrosion resistance of 316 SS in
subcritical water (containing oxygen and chloride) by preventing corrosive substances from contacting the
alloy substrate.

Co-author:

Shuwei Guo, Donghai Xu, Zhijiang Ma, Jianqiao Yang, Yanmeng Gong, Yuzhen Wa

Translation or Not:

No

Date of Publication:

2020-03-03