Effect of sulfate on the pitting potential of austenitic stainless steels 18Cr8Ni and 17Cr6Mn5Ni in chloride media

Abstract

Pitting corrosion resistance of two austenitic stainless steels, 18Cr8Ni (Type 304L or UNS S30403 stainless steel) and 17Cr6Mn5Ni, was evaluated in three electrolytic solutions containing a fixed concentration of 0.6M sodium chloride and different additions of sodium sulfate, 0.06M, 0.15M or 0.6M. Cyclic potentiodynamic polarization tests were performed on as-received samples and on specimens annealed at 1010°C, 1040°C, 1070°C or 1100°C. The best pitting corrosion resistance was presented by the 17Cr6Mn5Ni steel annealed at 1070°C or 1100°C, with lower delta ferrite contents, in the electrolyte with the highest sulfate concentration. It can be found that the addition of sodium sulfate inhibits pitting corrosion and has a better inhibitor effect in the high manganese steel.

Preliminary investigation on the effect of irradiation on tribocorrosion behavior of 316L stainless steel alloy

“…In the electrolyte with the sulfate concentration. It can be found that the addition of sodium sulfate inhibits pitting corrosion and has a better inhibitor effect in SS (Calderón-Hernández, Hincapíe-Ladino, Magnabosco, & Alonso-Falleiros, 2019;Vazquez-Arenas & Pritzker, 2010). In the steels used in the present investigation, there is not expected a considerable occurrence of MnS due to low S content.…”

“…The charge transfer resistance (reaction resistance) of the corrosion reaction increased as a result of increasing the diameter of the semicircle which increases with increasing the exposure time. The impedance plots that have not appeared as a semicircle at different times for the samples that have not been exposed to irradiation may be assigned for the frequency dispersion in addition to the inhomogeneity of the surface (Calderón-Hernández et al, 2019).…”

Plasma Electrolytic Polishing—An Ecological Way for Increased Corrosion Resistance in Austenitic Stainless Steels

“…According to the authors [43,44], the passivation effect of sulfate ions plays an important role in the formation of a highly resistant passive film. The authors [45] explain the increase in The use of (NH 4 ) 2 SO 4 solution as an electrolyte for the plasma polishing process may have contributed to the high corrosion resistance of both PEP and PPEP surfaces. According to the authors [43,44], the passivation effect of sulfate ions plays an important role in the formation of a highly resistant passive film.…”

“…According to the authors [43,44], the passivation effect of sulfate ions plays an important role in the formation of a highly resistant passive film. The authors [45] explain the increase in resistance of the austenitic stainless steel to the pitting by an adsorption of sulfate anions on the passive film surface.…”