Effect of Specific Magnetic Susceptibility of AISI 304 and 08Kh18N10 Steels on Their Limiting Potentials in Chloride-Containing Environments

• Published in: Materials science (New York, N.Y.) Vol. 59; no. 6; pp. 649 - 657
• Main Authors: Narivskyi, O. E., Snizhnoi, G. V., Pulina, T. V., Snizhnoi, V. L., Solidor, N. A.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.05.2024; Springer Nature B.V
• Subjects: Austenite; Austenitic stainless steels; Characterization and Evaluation of Materials; Chemistry and Materials Science; Chloride resistance; Corrosion effects; Corrosion potential; Corrosion resistance; Corrosion resistant steels; Crevice corrosion; Criteria; Damage; Heat exchangers; Hysteresis loops; Magnetic permeability; Materials Science; Parameters; Solid Mechanics; Solid solutions; Structural Materials; specific magnetic susceptibility; austenite; limiting potentials; crevice corrosion; chloride-containing media; structural heterogeneity
• ISSN: 1068-820X; 1573-885X
• DOI: 10.1007/s11003-024-00824-4

The resistance of AISI 304 and 08Kh18N10 steels to crevice corrosion in chloride-containing media was studied using potential-dynamic methods. The preset gap width of 0.3 mm between the sample and the counter body simulates the gap between adjacent plates of plate-like heat exchangers. The area of the hysteresis loop of the constructed anode potential-dynamic curves of the forward and reverse stroke was used to compare the volume of local damage caused by crevice corrosion of the studied steels. The maximum areas of the steel hysteresis loop and the volume of local corrosion damage in the ingots with the lowest (2.23×10 –8 and 2.24×10 –8 m 3 /kg) and highest (2.31×10 –8 m 3 /kg) values of the specific paramagnetic susceptibility χ 0 of austenite were established. The free corrosion potential E corr of steels intensively shifts in the negative direction (from –0.28 up to –0.41), and the repassivation E rp and crevice corrosion E crev – in the positive direction from –0.38 up to –0.29 and from –0.1 to 0.1 V, respectively, with an increase in the parameter χ 0 from 2.23×10 –8 up to 2.25×10 –8 m 3 /kg, which contributes to an increase in their ∆ E -criterion from 0.02 up to 0.69 V and resistance to crevice corrosion. This is because, in this range of values, the change in the χ 0 parameter is determined by deviations in the content of C, N, S, P, and Cr in the solid solution of austenite in steels. With an increase in the parameter χ 0 of steels to 2.31×10 –8 m 3 /kg, their potential E corr shifts in the positive direction from –0.41 up to –0.32, and E rp , E crev – in the negative direction from 0.29 up to 0.15 and from 0.10 up to –0.02 V, respectively, which contributes to a decrease in the ∆ E criterion of steels from 0.65 up to 0.14 V and their resistance to crevice corrosion. The χ 0 parameter of steels is an integral characteristic of the paramagnetic state of austenite and can be used to assess their resistance to crevice corrosion in chloride-containing media.