On the bacterial communities associated with the corrosion product layer during the early stages of marine corrosion of carbon steel

Scale-fragment formation impairing geothermal energy production: interacting H2S corrosion and CaCO3 crystal growth

“…Next to these corrosive constituents, the high thermal fluid temperatures (reaching 141 °C in the aquifer) and high fluid discharges (up to 135 l/s) promote efficient and rapid steel corrosion. In the carbonate scales, we find no distinct evidence (e.g., dendritic filaments) of microbially influenced Fe corrosion and/or CaCO 3 precipitation (Fan et al 2013;Lanneluc et al 2015) likely precluded by the hostile high fluid temperatures (Takai et al 2008;Lerm et al 2013). An origin of the sulfide layers from steel corrosion is further supported by the relatively low dissolved metal concentrations of the respective thermal waters (e.g., Fe ≤380 µg/l, Cu ≤2, Zn ≤17, Ni ≤26 µg/l; Seibt 2010).…”

“…Reducing conditions in aquifers and geothermal wells typically result in H 2 S-based corrosion and formation of various metal sulfides, while (intermittent) oxidizing conditions support the occurrence of iron-(oxy) hydroxides (Valdez et al 2009;Bai et al 2014). Steel corrosion and scaling processes may further be affected (e.g., catalyzed) by diverse microbial communities, i.e., playing an active (e.g., changing hydrochemistry) or passive (e.g., being a substrate) role for corrosion/scale mineral crystallization (Lanneluc et al 2015;Würdemann et al 2016).…”

Localized corrosion of carbon steel in marine media: Galvanic coupling and heterogeneity of the corrosion product layer

“…The inner stratum is in this case covered by an outer stratum mainly made of FeOOH compounds which shows that O 2 reacts with the Fe(II)-based compounds constituting the inner stratum. O 2 is also consumed by the aerobic micro-organisms that colonize the corrosion product layer [36]. As a result, the layer covering the anodic zones of the metal hinders strongly the transport of dissolved oxygen from seawater to metal surface.…”

“…It was previously shown that SRB were always present and active in the inner black stratum of the corrosion product layer [21] which explains why a large proportion of FeS is formed in any case [21][22][23]. The formation of FeS begins in the first deaerated zones of the steel surface and is associated with the development of SRB [36]. The outer stratum was also analyzed (results not shown).…”

A Novel Approach for the Evaluation of Under Deposit Corrosion in Marine Environments Using Combined Analysis by Electrochemical Impedance Spectroscopy and Electrochemical Noise

“…As exposure times elapsed, the accumulation of formed corrosion products (mainly composed of oxides and hydroxides of iron i.e. Fe(II,III) oxides such as magnetite (Fe3O4), goethite (α-FeOOH), lepidocrocite (γ-FeOOH) [63,64]) occurs that results in an increasing force on the deposited layer [10]. Accordingly, detachment of nearby deposits takes place and the barrier characteristics will be faded gradually, i.e.…”