Titre : Aluminium accumulation in mussel Mytilus edulis: laboratory investigation
Année : 2009
Auteur(s) : Mao A. Caplat Ch. Mahaut ML. Pineau S. Barillier D.
Abstract : Non disponible
SETAC Europe 19th Annual Meeting, 31 May – 4 June 2009, Götegorg, Sweden
Titre : Comportement des aciers inoxydables exposés en milieu marin
Année : 2009
Auteur(s) : Antony H.
Abstract : Non disponible
lundi de la mécanique - CETIM
Titre : Installation véhiculant ou stockant de l'eau - Matériaux & Corrosion
Année : 2009
Auteur(s) : Antony H.
Abstract : Non disponible
USIDO
Titre : Formation of the Fe(II-III) hydroxysulphate green rust during marine corrosion of steel associated to molecular detection of dissimilatory sulfite-reductase
Année : 2008
Auteur(s) : Pineau S. Sabot R. Quillet L. Jeannin M. Caplat Ch. Dupont-Morral I. Refait Ph.
Titre : Process and Efficiency of In Situ Experimentation for Accelerated Corrosion Studies, in French Marine Ports
Année : 2008
Auteur(s) : Pineau S. Lefèvre Y. Dupont-Morral I. Marsset B. Scherrer P. Auzeby C. Bénaïssa B.
Abstract : Non disponible
Material Performance, October 2008, p. 2-6
Titre : The study of relationship between diversity of bacterial biofilms and marine corrosion of carbon steel in harbour environments
Année : 2008
Auteur(s) : Pineau S. Ghiglione JF. Quillet L. Caplat Ch. Refait Ph.
Abstract : Here is reported investigation aimed to elucidate relationship between accelerated marine corrosion of carbon steel and community structure of bacterial biofilms associated with corrosion products. The study was conducted in three different French coastal regions (English Channel, Atlantic Ocean and Mediterranean Sea). SEM-EDX, ICP-AES, XRD and micro-Raman spectrometry revealed stratification of corrosion products based on iron oxidation state, regardless of geographical location. Molecular biology techniques and standard cultivation methods demonstrated that bacteria in corrosion products were abundant and highly diverse. Moreover, corrosion products contained many species of diatoms and multicellular organisms. Characterisation of cultivable bacteria and culture-independent molecular fingerprinting method (CE-SSCP) revealed more than 20 bacterial ribotypes in the deposits. Molecular detection of sulphate-reducing bacteria (SRB) was carried out using dissimilatory sulfite-reductase gene (dsrAB) and 16S rDNA probes specific for six SRB sub-groups.
The results of microbiological analysis demonstrated that the composition and diversity of bacterial populations associated with corrosion products are determined by the chemistry of different regions, i.e. steel surface, corrosion product surface and green rust / oxy-hydroxide interface, without clear stratification. Moreover, the study confirmed that, irrespective of the site investigated, bacterial species detected in corrosion products differed from the ones present in bulk water, thus emphasising the importance of biofilm sampling when investigating corrosion failures.
In view of the obtained results, the role of green rust as sulphate reservoir, the localised acidification induced by biogenically produced sulphur, the plausible role of extracellular polymeric substances in connecting bacterial cells and mineral corrosion products and the impact of multicellular organisms on the corrosion product stability are discussed.
14th International Congress on Marine Corrosion and Fouling July 27-31, 2008 Kobe, Japan
Titre : Biofilm et matériaux : je t’aime moi non plus ». XIème colloque du Groupe Français de Bioélectrochimie
Année : 2008
Auteur(s) : Pineau S.
Abstract : A une époque où la tendance serait à la stérilisation généralisée, les biofilms sont souvent une source de problèmes sanitaires et industriels, liés à des effets toxiques mais également à des impacts sur les infrastructures (modification des propriétés de surface ou corrosion par exemple). Ces communautés biologiques, de l’échelle micrométrique à centimétrique selon la thématique (biofilms bactériens ou évolution en macro-biofilms pluricellulaires), présentent une affinité toute particulière pour la plupart des matériaux, métalliques ou non. Il s’agit donc d’un processus normal, naturel et généralement bénéfique d’un point de vue écologique. Néanmoins, bien que les matériaux soient conçus pour résister à un environnement donné, les micro-organismes viennent fréquemment perturber le sommeil des gestionnaires de ces structures. Difficiles à modéliser, à prédire et à maîtriser, que ce soit pour l’expérimentation scientifique ou pour le suivi industriel, ces interactions entre biofilms et matériaux concernent tous les domaines de compétences mais principalement la science des matériaux, la microbiologie et l’électrochimie. Cette communication pluridisciplinaire, parfois laborieuse, offre de nombreuses perspectives de recherche. Une partie de cette problématique est illustrée par des exemples issus de cas industriels, particulièrement en eau de mer, où la distinction des frontières minéral/organique et bénéfique/préjudiciable est discutée.
Lacanau-Océan, 29 septembre - 2 octobre 2008
Titre : Carbonate and sulphate green rusts – Mechanisms of oxidation and reduction
Année : 2008
Auteur(s) : Antony H. Legrand L. Chaussé A.
Abstract : The oxidation and reduction of carbonate, GR(CO3), and sulphate, GR(SO4), green rusts (GR) have been
studied through electrochemical techniques, electrochemical quartz crystal microbalance (EQCM), FTIR,
XRD and SEM. The used samples were made of thin films electrodeposited on gold substrate. The results
from the present work, from our previous studies and from literature were compiled in order to establish
a general scheme for the formation and transformation pathways involving carbonate or sulphate
green rusts. Depending on experimental conditions, two routes of redox transformations occur. The first
one corresponds to reaction via solution and leads to the formation of ferric products such as goethite
or lepidocrocite (oxidation) or to the release of FeII ions into the solution (reduction) with soluble
FeII–FeIII complexes acting as intermediate species. The second way is solid-state reaction that involve
conversion of lattice Fe2+ into Fe3+ and deprotonation of OH groups in octahedra sheets (solid-state oxidation)
or conversion of lattice Fe3+ into Fe2+ and protonation of OH groups (solid-state reduction). The
solid-state oxidation implies the complete transformation of GR(CO3) or GR(SO4) to ferric oxyhydroxycarbonate
exGRc-Fe(III) or ferric oxyhydroxysulphate exGRs-Fe(III), for which the following formulas
can be proposed, FeIII
6(OH)(12-2y)(O)(2+y)(H2O)(y)(CO3) or FeIII
6(OH)(12-2z)(O)(2+z)(H2O)(6+z)(SO4) with 0 <=y
or z<=2. The solid-state reduction gives ferrous hydroxycarbonate exGRc-Fe(II) or ferrous hydroxysulphate
exGRs-Fe(II), which may have the following chemical formulas, [FeII
6(OH)10(H2O)2]·[CO3, 2H2O] or
[FeII
6(OH)10(H2O)2]·[SO4, 8H2O].
Titre : Study of FeII/FeIII ratio in thin films of carbonate or sulphate green rusts obtained by potentiostatic electrosynthesis
Année : 2008
Auteur(s) : Antony H. Labrit A. Rouchaud JC. Legrand L. Chaussé A.
Abstract : Thin films of carbonate or sulphate green rusts were synthesised from potentiostatic oxidation of solutions
containing ferrous species and bicarbonate or sulphate ions at slightly alkaline pHs and ambient
temperature. The thin films were characterised by means of electrochemical quartz crystal microbalance,
scanning electron microscopy, X-ray diffraction and infrared reflection–absorption spectroscopy.
The composition of carbonate or sulphate green rusts was studied through chemical titration, inductively
coupled plasma-optical emission spectroscopy (ICP-OES) and gravimetry and is as follows:
[FeII
(2R)FeIII
2(OH)(4R'2R'+6)(H2O)(2R'-2)]2R'+·[R'CO3, (2R-{3 or 4}R' + 2)·H2O]2R'-
and [FeII
(2R)FeIII
2(OH)(4R?2R''+6)(H2O)(2R''-2)]2R''+·[R''SO4, (4R-4R' + 4)·H2O]2R''-
FeII/FeIII ratio R depends on the concentration of soluble ferrous species that are located at electrode
surface during the potentiostatic synthesis and increases as the potential is made more negative. R-values
are in the ?2–2.5 range for carbonate green rust, and in the ~2–2.2 range for sulphate green rust. The
obtained R'- and R''-values are 1–1.3 and 1.1–1.4 for carbonate and sulphate green rusts, respectively.
The present study excludes the existence of green rusts with FeII/FeIII ratio, R, lower than 2. The R-values
lower than 2 that are found in some studies might relate to mixtures of the green rust and its solid-state
oxidation product exGR-Fe(III) (ferric oxyhydroxycarbonate or ferric oxyhydroxysulphate) rather than to
pure green rust.
Titre : Experimental evidence of the evolution of the oxide barrier layer during corrosion of low alloyed steels
Année : 2008
Auteur(s) : Martin F. Antony H. Bataillon Ch.
Abstract : In the framework of the study of corrosion of nuclear waste packages in geological disposal conditions, a general corrosion modelling has been suggested to predict their long term behaviour. This corrosion model (Diffusion Poisson Coupled Model) associated to the code CALIPSO is able to describe the iron release in Fe(II) and Fe(III) cations at the external interface, as well as the iron and electrons fluxes across the system. Introduction of the oxygen flux will be the next step in the modelling because it is responsible for the formation of the oxide barrier layer.
In order to bring entrance data for this model, a non destructive method has been developed to estimate the thickness of the oxide layer. This method is based on the EDS analysis. Combining ex situ gravimetry measures and the measured oxide layer thicknesses gives an estimation of the Fe released in solution function of immersion time. The first results obtained on a pre-oxidised Armco Fe sample (thus covered by an oxide layer of a definite thickness) in a deaerated Tris buffered solution are presented.
These preliminary observations show that both outer and inner interfaces move towards the metal bulk with immersion time (see figure), which confirms the growth/dissolution mechanisms at the inner and outer interfaces described in the PDM. Moreover, the corrosion rate decreases to reach a quasi-stationary state. This is materialised by a nearly constant thickness of the oxide film for long times.
