Biofilm development during ennoblement of stainless steel in Baltic Sea water: A microscopic study

Microbial Degradation of Materials: General Processes

“…A correlation between microbial activity and deposition of MnO x has been established by Dickinson et al [146], and similar observations have also been reported [147]. Specific mechanisms of corrosion are discussed previously [148] and also in Chapter 39 of this book.…”

Rainbow fringes around crevice corrosion formed on stainless steel AISI 316 after ennoblement in seawater

“…To date, the mechanism of ennoblement is still poorly understood. The increase in OCP of stainless steel AISI 316 by about 500 mV was observed after microbial colonization on passive metals surface [8]. Theoretically, E corr ennoblement should increase the probability for pitting and crevice corrosion initiation and propagation of some passive alloys [14].…”

“…The modification of microbial, physical, and chemical micro-environment at biofilm-metal interface is generally believed to be the reason [1][2][3][4][5][6][7][8][9][10][11][12]. Beech et al discussed the impacts of biomineralization process, enzymes, and extracellular polymeric substances (EPS) on electrochemical reactions at the biofilm-metal interface [13].…”

Electrochemical techniques used in MIC studies

“…Influence of biofilm on the ennoblement has been ascribed to very different mechanisms, such as electrochemical reduction of manganic oxide biofouling formed on surfaces by the activity of manganese oxidizing bacteria [1][2][3]; effects of changes of H 2 O 2 concentration in biofilms [4]; pH decrease in biofilm/metal surfaces [5]; catalytic effects of enzymes entrapped in the EPS [6,7]. Mittila et al studied the development of biofilm on stainless steel during the increase of open circuit potential in natural seawater [8]. The cathodic and anodic reactions are related to semi-conducting properties of passive films, then the interaction between bacteria and p-type or n-type semiconductors may be involved in the ennoblement [9].…”