TY - JOUR
T1 - Corrosion of Stainless Steels S31603, S31655, and S32101 in Sulfuric Acid Solutions
T2 - Effects of Concentration, Chlorides, and Temperature
AU - Huttunen-Saarivirta, E.
AU - Isotahdon, E.
AU - Lindgren, M.
AU - Mardoukhi, A.
AU - Mocnik, P.
AU - Kosec, T.
AU - Jorcin, J. B.
AU - Mameng, S. Hägg
AU - El Ouazari, Y.
AU - Wegrelius, L.
N1 - Funding Information:
The financial support by EIT Raw Materials and the partner organizations: VTT Technical Research Centre of Finland Ltd., Metso Outotec Finland Oy, ZAG Slovenian National Building, and Civil Engineering Institute, Tecnalia, Outokumpu Stainless AB, Boliden Harjavalta Oy, Ferritico AB, and Data Measuring Systems DMS, for the CORTOOLS project under the acceleration program (Project No. 18158) is gratefully acknowledged.
Publisher Copyright:
© 2022 AMPP.
PY - 2022/10
Y1 - 2022/10
N2 - This study investigates the corrosion behavior of three stainless steel grades at two H2SO4 concentrations, namely 1 wt% and 10 wt%, with varying NaCl concentrations in the range from 500 mg/L to 10,000 mg/L. Dissociation of sulfuric acid yields the hydrogen (H+) and sulfate (SO24-) ions, the former of which lowers the pH value of a solution while the latter increases the concentration of sulfate ions that act as a corrosion inhibitor. The equilibrium chemistry of the solutions was defined at the test temperatures of 22°C, 50°C, 90°C, and 130°C, and correlated with the observations on the electrochemical and microstructural examination of the materials. The results showed clear differences in the main corrosion form between the two H2SO4 concentrations. In 1 wt% H2SO4, pitting was the major form of corrosion attack in the presence of chlorides, whereas uniform corrosion dominated in 10 wt% H2SO4. The pitting corrosion tendency for the three stainless steel grades under various test conditions was consistent, but there were differences in their resistance to uniform corrosion. The chloride-to-sulfate activity ratio, a(Cl-)=a(SO24-), was found to be the key parameter in defining the occurrence of pitting corrosion for all three alloys. In H2SO4-NaCl systems, no pitting occurred at the activity ratio a(Cl-)=a(SO24-) below 10, with higher values inducing pitting attack, particularly in 1 wt% H2SO4. The described novel results are presented and discussed in this paper.
AB - This study investigates the corrosion behavior of three stainless steel grades at two H2SO4 concentrations, namely 1 wt% and 10 wt%, with varying NaCl concentrations in the range from 500 mg/L to 10,000 mg/L. Dissociation of sulfuric acid yields the hydrogen (H+) and sulfate (SO24-) ions, the former of which lowers the pH value of a solution while the latter increases the concentration of sulfate ions that act as a corrosion inhibitor. The equilibrium chemistry of the solutions was defined at the test temperatures of 22°C, 50°C, 90°C, and 130°C, and correlated with the observations on the electrochemical and microstructural examination of the materials. The results showed clear differences in the main corrosion form between the two H2SO4 concentrations. In 1 wt% H2SO4, pitting was the major form of corrosion attack in the presence of chlorides, whereas uniform corrosion dominated in 10 wt% H2SO4. The pitting corrosion tendency for the three stainless steel grades under various test conditions was consistent, but there were differences in their resistance to uniform corrosion. The chloride-to-sulfate activity ratio, a(Cl-)=a(SO24-), was found to be the key parameter in defining the occurrence of pitting corrosion for all three alloys. In H2SO4-NaCl systems, no pitting occurred at the activity ratio a(Cl-)=a(SO24-) below 10, with higher values inducing pitting attack, particularly in 1 wt% H2SO4. The described novel results are presented and discussed in this paper.
KW - chloride
KW - pitting
KW - stainless steel
KW - sulfate
KW - sulfuric acid
KW - uniform corrosion
UR - http://www.scopus.com/inward/record.url?scp=85143665934&partnerID=8YFLogxK
U2 - 10.5006/4122
DO - 10.5006/4122
M3 - Article
AN - SCOPUS:85143665934
SN - 0010-9312
VL - 78
SP - 943
EP - 962
JO - Corrosion
JF - Corrosion
IS - 10
ER -