Effects of Leptothrix discophora on the potential behavior of stainless steels

Leena Carpen, Laura Raaska, Kirsi Kujanpää, Tero Hakkarainen

    Research output: Contribution to journalArticleScientificpeer-review

    4 Citations (Scopus)

    Abstract

    Biofilm formation and electrochemical behavior of stainless steel have been studied in well water, in tap water and in water taken from fire extinguishing system. Some of the waters have been modified by adding manganese ions as well as in some cases acetate and yeast extract as a nutrient. Manganese oxidizing bacteria Leptothrix discophora has been used in these studies. To eliminate crevices in the specimen holder and to simulate reasonably well the conditions in fire‐extinguishing systems where the water is stagnant most of the time, a tape test arrangement with very slow flowing rate has been used in most of these studies. Also specimens with heat tint areas produced by heating inductively a small section of the specimen under flowing argon shielding gas were used in these studies. The results of these tape tests show that manganese oxidizing bacteria are able to increase the potential of both the base material (stainless steel UNS S30400) and of specimens with heat tint areas in well water, in tap water and in water taken from fire extinguishing system. Manganese oxidizing bacteria are also able to increase the cathodic reaction and thus enhance the initiation of corrosion. However, the increase of potential is not alone enough to start the corrosion. In these tests corrosion was initiated only in the specimens with heat tint areas in one of the waters taken from fire extinguishing system. No corrosion was detected in the specimens exposed to the well water or to the tap water used in these tests.
    Original languageEnglish
    Pages (from-to)515-519
    JournalMaterials and Corrosion
    Volume54
    Issue number7
    DOIs
    Publication statusPublished - 2003
    MoE publication typeA1 Journal article-refereed

    Keywords

    • stainless steel
    • potential behaviour
    • Leptothrix discophora
    • biofilm formation
    • manganese oxidizing bacteria

    Fingerprint Dive into the research topics of 'Effects of Leptothrix discophora on the potential behavior of stainless steels'. Together they form a unique fingerprint.

  • Cite this