Effect of polishing on electrochemical behavior and passive layer composition of different stainless steels

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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2020-08
Major/Subject
Mcode
Degree programme
Language
en
Pages
12
1-12
Series
Materials, Volume 13, issue 15
Abstract
In the present paper, the effect of different polishingmethods (mechanical and electrochemical) on passive layer chemistry and the corrosion behavior of stainless steels is investigated. It was found that CrNiMo austenites have a substantially better corrosion behavior than CrMnN ones. The nickel is enriched underneath the passive layer, while manganese tends to be enriched in the passive layer. It was also noted that immersion of manganese into an electrolyte preferentially causes its dissolution. It was found that high amounts of chromium (27.4%), molybdenum (3.3%), nickel (29.4%), with the addition of manganese (2.8%) after mechanical grinding, generates a better corrosion resistance than after electrochemical polishing. This ismost likely because of the introduction of phosphates and sulfates into its structure, which is known for steels with a high amount of manganese. For highly alloyed CrNiMo steels, which do not contain a high amount of manganese, the addition of phosphates and/or sulphates via the electropolishing process results in a decrease in pitting corrosion resistance, which is also observed for highmanganese steels. Electropolished samples show detrimental corrosion properties when compared to mechanically polished samples. This is attributed to substantial amounts of sulfate and phosphate from the electropolishing electrolyte present in the surface of the passive layer.
Description
Keywords
Electrochemical behavior, Electropolishing, Mechanical polishing, Passivity, Stainless steels, XPS
Other note
Citation
Rokosz , K , Solecki , G , Mori , G , Fluch , R , Kapp , M & Lahtinen , J 2020 , ' Effect of polishing on electrochemical behavior and passive layer composition of different stainless steels ' , Materials , vol. 13 , no. 15 , 3402 , pp. 1-12 . https://doi.org/10.3390/ma13153402