Effects of H2S and pH on Tafel slopes in electrochemical corrosion of high strength carbon steel S-135 in alkaline brines

R. Feng, J. Beck, M. Ziomek-Moroz, S. N. Lvov

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Effects of H2S and pH on electrochemical corrosion of high-strength low-alloy carbon steel, Grade S-135, were investigated through Tafel slopes. Linear sweep voltammetry (LSV) was conducted in 5 %wt. NaCl solutions of pH 7.9, 10.7, and 12.4 with four H2S partial pressures (pH2S) ranging from 0 to 69 kPa at 85 oC after 60 hours of exposure. Anodic limiting current was observed without H2S, but disappeared at higher pH2S. Cathodic LSV plots did not show limiting currents, suggesting that H2O was the main reactant for the hydrogen evolution reaction at high pH. Both anodic and cathodic currents increased at 69 kPa pH2S compared to 0 kPa. Electrochemical reaction mechanisms were discussed based on anodic and cathodic Tafel slopes. The Tafel slopes from LSV were generally larger than those obtained from electrochemical frequency modulation. Different Tafel slopes could result in a discrepancy in corrosion rate by a factor of 5.

Original languageEnglish (US)
Title of host publicationCorrosion General Session
EditorsR. G. Buchheit, S. Virtanen
PublisherElectrochemical Society Inc.
Pages59-71
Number of pages13
Edition17
ISBN (Electronic)9781607685395
DOIs
StatePublished - Jan 1 2016
EventCorrosion General Session - 229th ECS Meeting - San Diego, United States
Duration: May 29 2016Jun 2 2016

Publication series

NameECS Transactions
Number17
Volume72
ISSN (Print)1938-5862
ISSN (Electronic)1938-6737

Other

OtherCorrosion General Session - 229th ECS Meeting
CountryUnited States
CitySan Diego
Period5/29/166/2/16

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All Science Journal Classification (ASJC) codes

  • Engineering(all)

Cite this

Feng, R., Beck, J., Ziomek-Moroz, M., & Lvov, S. N. (2016). Effects of H2S and pH on Tafel slopes in electrochemical corrosion of high strength carbon steel S-135 in alkaline brines. In R. G. Buchheit, & S. Virtanen (Eds.), Corrosion General Session (17 ed., pp. 59-71). (ECS Transactions; Vol. 72, No. 17). Electrochemical Society Inc.. https://doi.org/10.1149/07217.0059ecst