Papers by Jean-Pierre MILLET
Electrochimica Acta, 1981
Resume L'utilisation d'une electrode a disque tournant de platine sur laquelle de l'a... more Resume L'utilisation d'une electrode a disque tournant de platine sur laquelle de l'aluminium est prealablement depose, a permis de determiner le mecanisme de la reaction cathodique dans l'electrolyse des bains cryolithe—alumine. Celui-ci comporte trois etapes a l'interieur de la couche de Nernst: la premiere est une etape de dissociation de l'ion ALF 3− 6 a une certaine distance δ′ de l'electrode, calculable, qui separe les ions Al 3+ et F − ; la seconde une etape de decharge des ions Al 3+ diffusant vers la cathode et la troisieme, a une distance δ″ de l'electrode, une etape de reaction des ions F − avec les ions AlF − 4 pour redonner les ions AlF 3− 6 . Quant aux ions Na + , qui transportent la quasitotalite du courant, ils interviennent dans le mecanisme de telle sorte que la neutralite electrique soit respectee.
Electrochimica Acta, May 1, 2006
Influence of hydrodynamic conditions on the behaviour of an inhibitor film used in the high speed... more Influence of hydrodynamic conditions on the behaviour of an inhibitor film used in the high speed mechanical field is studied. Experimentations are realized with a Rotating Disk Electrode (RDE). Electrochemical Impedance Spectroscopy (EIS) is carried out at the corrosion potential and also at anodic and cathodic over voltages under various rotation rates and after different immersion times. EIS technique is used to determine the beneficial effect of hydrodynamic conditions on the film formation. This technique characterizes also inhibitive layer modifications for high electrode rotation speeds and after long immersion times. Different analyses, XPS and AFM, were carried out and have confirmed film structure evolution with flow conditions.
Electrochimica Acta, Nov 1, 2005
This paper deals with the characterization of an environment-friendly corrosion inhibitor formula... more This paper deals with the characterization of an environment-friendly corrosion inhibitor formulated for industrial cutting fluids. Polarization measurements and electrochemical impedance spectroscopy (EIS) tests reveal the formation of a 3D film at the interface metal/elecrolyte. This film blocks iron ions oxidation by forming a barrier on the metallic surface. Studies concerning, respectively, inhibitor concentration, immersion time and temperature show that effects of these three parameters are strongly linked and influence considerably the protective effect of the inhibitor. XPS analyses confirm formation of an inhomogeneous layer submitted to a water-uptake with time when inhibitor is not added in necessary concentration.
Journal of Applied Electrochemistry, Sep 1, 1982
Dans un précédent travail, les conditions de préparation d'un... more Dans un précédent travail, les conditions de préparation d'un alliage PbCa par électrolyse ignée ont été établies. Ici, nous montrons que le même processus peut être utilisé pour le baryum et le strontium avec le même résultat, c'est-à-dire saturation de l'alliage avec d'excellents rendements de courant. De plus, il a été confirmé que l'étain, le zinc et l'aluminium pouvaient être
BULL LIAISON LAB PONTS CHAUSS, 1978
DETERIORATION ON BRIDGE PIERS AT THE LEVEL OF PRESTRESSING CABLE ANCHORAGE POINTS LED TO AN INVES... more DETERIORATION ON BRIDGE PIERS AT THE LEVEL OF PRESTRESSING CABLE ANCHORAGE POINTS LED TO AN INVESTIGATION INTO THE CAUSE OF STEEL CORROSION TO SEE WHETHER THE LATTER IS DUE TO ATMOSPHERIC CORROSION (CARBONATION) OR OTHER TYPES OF CORROSION. X-RAY QUALITATIVE MINERALOGICAL ANALYSIS FACILITATES THE RAPID IDENTIFICATION OF THE CAUSES OF POLLUTION. AS REGARDS CARBONATION, THE METHOD CAN ONLY BE APPLIED TO CONCRETE WHICH DOES NOT CONTAIN CALCITIC AGGREGATES. TO OBSERVE CARBONATION IN DEPTH AND THUS TO GAIN DATA ON THE COVERING OF THE STEEL, SAMPLES ARE CUT INTO SUCCESSIVE SLICES WHICH ARE ANALYZED IN TURN. THIS X-RAY DIFFRACTION ANALYSIS GIVES INDICATIVE RESULTS WHICH ARE DIFFICULT TO USE AS THE GRADING OF THE INGREDIENTS MUST BE TAKEN INTO ACCOUNT. AN AVERAGE QUANTITATIVE ANALYSIS OF EACH SLICE WAS CONDUCTED AFTER ELIMINATION OF THE COARSE AGGREGATES. CRUSHING WAS USED. A COMPARISON IS MADE BETWEEN THE INTENSITY OF THE DIFFRACTION BANDS OF THE LIME AND CALCITE FOR THE VARIOUS SLICES STUDIED, AND THAT OF A SERIES OF CONTROL MIXTURES. FOR EACH CONTROL MIXTURE IT IS POSSIBLE TO CALCULATE THE RATE OF CARBONATION WITH A PERCENTAGE OF NON-CARBONATED CALCIUM HYDROXIDE AND A PERCENTAGE OF CALCIUM HYDROXIDE CORRESPONDING TO THE PERCENTAGE OF CALCITE PRESENT IN THE MIXTURE AND TO DEDUCT THAT OF CONCRETE.
Le Centre pour la Communication Scientifique Directe - HAL - Université de Nantes, 2001
Le Centre pour la Communication Scientifique Directe - HAL - memSIC, 2003
Le Centre pour la Communication Scientifique Directe - HAL - Université de Nantes, 2013
Le Centre pour la Communication Scientifique Directe - HAL - Inria, 2011
INSA de Lyon, Nov 1, 2010
Le Centre pour la Communication Scientifique Directe - HAL - Université de Nantes, 2005
ABSTRACT Thin films Al-Cu were deposited on glass substrates from composite targets by cathodic m... more ABSTRACT Thin films Al-Cu were deposited on glass substrates from composite targets by cathodic magnetron radio frequency (13,56 MHz) sputtering. The microstructure was studied by transmission electronic microscopy (TEM) and X ray diffraction(DRX) consisted of either only one phase cfcCu for the films with compositions equal or higher than 86,17 at.%Cu or the two phases cfcAl + the predicted θ (Al2Cu) phase for the compositions equal or lower than 45,99 at.%Cu. For the intermediate compositions, it was a mixture of the cfcAl phase + an unexpected phase which was identified as the Cu3Al phase with L12 type, Cu3Au structure and a measured lattice parameter of about 0,306 nm. A phase separation was observed for the first time in the binary Al-Cu alloys system, this one consisted of a mixture of the three distinct phases : cfcAl + cfcCu + Cu 3Al in the deposits of nominal composition Al-66.64 at.%Cu. The co-sputtered Al-Cu thin films are much harder than conventional corresponding alloys, the Vickers micro hardness and Young modulus increase regularly with copper concentration reaching respectively a maximum of about 8000 MPa and 200 GPa for the films with compositions close to equi-atomic compositions. The corrosion potential evolution of the co-sputtered Al-Cu thin films have been performed in an aerated neutral 37 g/l NaCl with a classical apparatus with three electrodes conducted by a microcomputer. The working area was about 0.5 cm 2. Two electrochemical test types are usually used for the study of the corrosion potential. The first consists in measuring the corrosion potential according to the time. The general interest of this one is the stabilization of the corrosion potential. The working time, after stabilization of the corrosion potential according to time was about one hour. The second test consists in measuring the corrosion potential E corr of the samples according to the corrosion current I corr. The working time after formation of the voltametric curve was also about one hour. The corrosion-potentials for all films are directly given by the microcomputer and are in agree with that extrapolated from stabilization and voltametric-curves. The corrosion potential was about -275 mV for the films with nominal 66.64 at.%Cu compositions and the general tendency is the ennoblement of the corrosion potential of the co-sputtered Al-Cu films with copper contents enrichment. Compared to corrosion potential of steel XC18 (about of -500 mV in the same conditions), the Al-Cu films containing less than 20 at.%Cu are anodic, for higher contents they are cathodic. In the first case, they can be used as sacrificial coatings for the cathodic protection of steel. But, some precautions are to be taken where the surfaces to be coated might be very well polished and cleaned, the deposits did not have any discontinuities which cause localized corrosion pitting.
Le Centre pour la Communication Scientifique Directe - HAL - Université de Nantes, Dec 1, 2016
We study copper corrosion inhibition by ethanolamine (ETA) with (0, 0.2 ,0.3,0.4,0.5) vol.% conce... more We study copper corrosion inhibition by ethanolamine (ETA) with (0, 0.2 ,0.3,0.4,0.5) vol.% concentrations in 100 ppm NaCl solution. This work is carried out by potentiodynamic measurements and Electrochemical Impedance Spectroscopy (EIS). The substrates' surface morphologies are examined by Scanning Electron Microscopy (SEM). ETA is characterized by NMR spectra of ETA 1 H and 13 C and Fourier Transform InfraRed Spectroscopy (FT-IR).Quantum chemical calculation (DFT) is conducted to correlate the adsorption mechanism with ETA molecule structure. The results show that ETA acts as a mixed inhibitor; so at 0.4 vol. %, the current density (i) and the polarization resistance (Rp) are respectively 0.8µA/cm 2 and 28.62 Ω.cm 2 with 99.78% corresponding efficiency. ETA adsorption obeys to Langmuir isotherm and takes place on copper surface through chemical and physical mixed-type adsorption.
Influence of the chloride amount on the corrosion resistance of two aluminium based materials (Al... more Influence of the chloride amount on the corrosion resistance of two aluminium based materials (AlMn and AlSi/AlMn/AlSi) was determined using electrochemical methods (free corrosion potential versus time, potentiodynamic curves and polarization resistance evolution versus time) at the room temperature. It was found that corrosion resistance of these materials decrease with the increasing amount of chloride and that AlSi/AlMn/AlSi presents a better behaviour in these media.
Les acides naphteniques sont des composes organiques que l'on trouve dans certains petroles b... more Les acides naphteniques sont des composes organiques que l'on trouve dans certains petroles bruts. Responsables lors du raffinage d'une corrosion de nature supposee electrochimique dans la gamme de temperatures 200°C-400°C, leur action corrosive reste mal connue, en particulier au niveau des mecanismes reactionnels. Il n'existe pour le moment que peu de solutions permettant de raffiner ces bruts "acides" sans risque. Notre etude entre dans le cadre de la comprehension de ces mecanismes avec notamment pour objectif la determination de la vitesse de corrosion induite par les acides naphteniques. Bien que tres resistifs, les bruts ont ete etudies avec une technique electrochimique non stationnaire, la Spectroscopie d'Impedance Electrochimique (SIE). Un systeme a deux electrodes a tout d'abord permis de determiner la contribution de la resistance d'electrolyte a l'impedance du systeme pour diverses temperatures ; des contributions interfaciales sont...
Materials Science Forum, 2004
ABSTRACT
Http Www Theses Fr, 2005
La fragilisation par l’hydrogene (FPH) est rencontree en milieu H2S sur les aciers faiblement all... more La fragilisation par l’hydrogene (FPH) est rencontree en milieu H2S sur les aciers faiblement allies utilises pour les tubes de cuvelage de forages petroliers. Pour une meilleure comprehension de ce mode de corrosion, le test standardise de rupture differee en traction (Nace TM 0177-96 Methode A) a ete instrumente par emission acoustique. Dans la configuration de test utilisee, l’etude d’aciers de sensibilite differente a la FPH revele l’existence de sources tres emissives (Hydrogen Induced Cracking, FeS), masquant d’autres sources (H2, Sulphide Stress Cracking). Dans le cas de la fissuration HIC, le suivi de l’energie acoustique cumulee montre que l’amorcage de ce type de fissuration interne sur des zones segregees de la microstructure est accelere par l’application d’une contrainte. Pour la fissuration SSC, le traitement statistique des donnees acoustiques permet de localiser l’endommagement plusieurs dizaines d’heures avant la rupture. Le mecanisme associe a la fissuration est lie a un amorcage surfacique de l’endommagement et est modifie par les conditions de chargement en hydrogene.
Materials Science Forum, 2003
ABSTRACT
Corrosion Science, 2013
ABSTRACT This paper presents the inhibitory properties of L-histidine on the corrosion of carbon ... more ABSTRACT This paper presents the inhibitory properties of L-histidine on the corrosion of carbon steel in weak acid media containing acetic acid/sodium acetate. The inhibition efficiencies obtained by weight loss measurements are in good agreement with values given by Tafel method and electrochemical impedance spectroscopy. The adsorption of L-histidine obeys the Langmuir isotherm and the negative values of Gibbs energy indicate that nature of interactions between inhibitor molecules and metal surface. Further, the inhibition effect was studied using scanning electron microscopy and energy dispersive X-Ray analysis.
Http Www Theses Fr, Nov 15, 2011
~ 3 ~ Je tiens également à remercier Robert di Folco et Robert Diemiaszonek pour leur aide et les... more ~ 3 ~ Je tiens également à remercier Robert di Folco et Robert Diemiaszonek pour leur aide et les conseils scientifiques qu'ils m'ont apportés, toujours avec le sourire. Je suis reconnaissante à Mesdames Doina MORARU, Jalila SECOND et Elena NEAGU qui, par leur dynamisme et leur gentillesse rendraient presque agréables les tâches administratives… Je remercie tous mes collègues des laboratoires (CorrIS et SGM): Claudiu,
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Papers by Jean-Pierre MILLET