Corrosion Behaviour of 316L Stainless Steel in Hot Dilute Sulphuric Acid Solution with Sulphate and NaCl

• Published in: Protection of metals and physical chemistry of surfaces Vol. 55; no. 1; pp. 148 - 156
• Main Authors: Jian Zhang, Ju, Pengfei, Wang, Chaoli, Dun, Yuchao, Zhao, Xuhui, Zuo, Yu, Tang, Yuming
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 2019; Springer Nature B.V
• Subjects: Austenitic stainless steels; Characterization and Evaluation of Materials; Chemistry and Materials Science; Chloride ions; Corrosion and Coatings; Corrosion products; Corrosion rate; Corrosion tests; Immersion tests (corrosion); Industrial Chemistry/Chemical Engineering; Inorganic Chemistry; Materials Science; Metallic Materials; Physicochemical Problems of Materials Protection; Sodium chloride; Sodium sulfate; Stainless steel; Sulfates; Sulfuric acid; Tribology; Uniform attack (corrosion); X ray photoelectron spectroscopy; hot dilute sulphuric acid; corrosion; sodium sulphate; 316L SS; corrosion products; sodium chloride
• ISSN: 2070-2051; 2070-206X
• DOI: 10.1134/S207020511901026X

The corrosion behaviour of 316L stainless steel (316L SS) in 10% H
2
SO
4
solution (94°C) with various concentrations of NaCl (0–0.085 mol/L) was studied by immersion corrosion test and polarization methods, combined with SEM/EDS, XPS and XRD tests. The influence of NaCl on the corrosion of 316L SS was investigated. The results showed that at lower NaCl contents (0–0.0085 mol/L), the steel presented a general corrosion characteristic with a higher corrosion speed and the corrosion rate increased with the NaCl content. At higher NaCl contents (≥0.017 mol/L), the corrosion rate decreased remarkably due to the protective corrosion products precipitation which contained metallic sulphates and NaHSO
4
. However, the higher concentration of chloride ions caused micron pitting-like local dissolution on the surface. The addition of Na
2
SO
4
effectively inhibited general corrosion of the steel because of a dense and continuous products layer enriched with more NaHSO
4
and metallic sulphates formed.