Jean-baptiste Jorcin - Academia.edu (original) (raw)

Papers by Jean-baptiste Jorcin

Research paper thumbnail of Spectroscopie d'impédance electrochimique locale : caracterisation de la de lamination des peintures et de la corrosion des alliages Al-Cu

En préambule à ce manuscrit, je souhaite exprimer ma reconnaissance et mes remerciements aux pers... more En préambule à ce manuscrit, je souhaite exprimer ma reconnaissance et mes remerciements aux personnes qui m'ont soutenu et aidé durant les années consacrées à la réalisation de ce travail. Dans un premier temps, je remercie monsieur Bernard Tribollet, directeur de recherche CNRS au sein du Laboratoire interface et systèmes électrochimiques (LISE) pour l'aide qu'il m'a apporté dtout au long de ce travail, et aussi pour avoir accepter de présider mon jury de thèse. Je tiens à remercier sincèrement monsieur Sébastien Touzain, maître de conférence à l'Uni

Research paper thumbnail of Investigation of the self-healing properties of shape memory polyurethane coatings with the ‘odd random phase multisine’ electrochemical impedance spectroscopy

Electrochimica Acta, Aug 1, 2010

This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit:

Research paper thumbnail of Galvanic Coupling Between Pure Copper and Pure Aluminum

Journal of The Electrochemical Society, 2008

Research paper thumbnail of Comparison of local electrochemical impedance measurements derived from bi-electrode and microcapillary techniques

Electrochimica Acta, Oct 1, 2009

In the present paper, local electrochemical impedance spectra were obtained on a 316L stainless s... more In the present paper, local electrochemical impedance spectra were obtained on a 316L stainless steel from two configurations: a dual microelectrode (bi-electrode) and microcapillaries. With the bi-electrode, the local impedance measurements were made from the ratio of the applied voltage to the local current density calculated from the application of the ohm's law. With the use of microelectrochemical cells, the specimen surface area in contact with the electrolyte is limited by the use of glass microcapillaries and the local impedance was defined from the ratio of the local potential to the local current restricted to the analysed surface area. Differences and similarities observed in local impedance spectra obtained with the two configurations were described.

Research paper thumbnail of Determination of the sensitized zone extension in welded AISI 304 stainless steel using non-destructive electrochemical techniques

Corrosion Science, Apr 1, 2008

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Research paper thumbnail of Contribution to a better understanding of different behaviour patterns observed with organic coatings evaluated by electrochemical impedance spectroscopy

Corrosion Science, Jun 1, 2009

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Research paper thumbnail of Delaminated areas beneath organic coating: A local electrochemical impedance approach

Corrosion Science, Jul 1, 2006

Local electrochemical impedance mapping was used to investigate delamination phenomena at the ste... more Local electrochemical impedance mapping was used to investigate delamination phenomena at the steel/epoxy-vinyl primer interface. The delamination occurred from an artificial defect (cutter scribing) and from ageing in a salt spray chamber. The samples were taken from the salt spray chamber after 20, 30 and 50 days of exposure. To observe delamination after ageing, the corrosion product layers were removed by a cathodic polarization at −1.5 V/SCE for 4 h. A non-aged reference sample was tested for comparison. Mapping was performed at 5 kHz. Initiation and propagation of the delamination were clearly observed. The delaminated surface areas measured by visual observations after the removal of the coating were lower than those determined by local electrochemical impedance mapping. The delamination mechanisms were discussed with reference to literature data.

Research paper thumbnail of Corrosion protection of carbon steel by an epoxy resin containing organically modified clay

Surface & Coatings Technology, May 1, 2007

This study focusses on the use of montmorillonite clay (MMT) treated with an organic compound (am... more This study focusses on the use of montmorillonite clay (MMT) treated with an organic compound (aminotrimethylphosphonic acid (ATMP)) and dispersed in an epoxy resin to improve corrosion protection of carbon steel. X-ray diffraction was performed to verify that the individual silicate layers were separated and dispersed in the epoxy resin. Corrosion resistance of the coated steel was evaluated by electrochemical impedance spectroscopy (EIS) and local electrochemical impedance spectroscopy (LEIS). Three systems were tested: the epoxy clear-coat, the epoxy resin containing 2 wt.% clay and the epoxy resin containing 2 wt.% clay modified by ATMP (ATMP-modified clay). From conventional EIS, it was shown that the incorporation of clay or ATMP-modified clay in the epoxy matrix significantly improved the barrier properties of the coating. The corrosion resistance of the carbon steel coated by the epoxy resin containing ATMP-modified clay was higher than that obtained for the system containing non-treated clay. Local electrochemical measurements performed on scratched samples revealed the inhibitive role of ATMP at the carbon steel/coating interface.

Research paper thumbnail of CPE analysis by local electrochemical impedance spectroscopy

Electrochimica Acta, 2006

Constant-phase elements (CPE) are used extensively in equivalent electrical circuits for fitting ... more Constant-phase elements (CPE) are used extensively in equivalent electrical circuits for fitting of experimental impedance data. The CPE behavior is generally attributed to distributed surface reactivity, surface inhomogeneity, roughness or fractal geometry, electrode porosity, and to current and potential distributions associated with electrode geometry. In this work, different electrochemical systems showing the CPE dependence in the high-frequency range for the overall impedance were considered. Local electrochemical impedance spectroscopy was found to provide a good means for assessing the influence of local variations on the CPE behavior seen in global impedance measurements. A separation between 2D and 3D distributions could be easily observed. In the case of a 2D distribution (AZ91 Mg alloy), the origin of the CPE behavior was the distribution of high-frequency resistance associated with the geometry of the disk electrode; whereas, the capacitance was independent of position. In the case of the aluminium electrode, the CPE behavior could be attributed to a combination of 3D and 2D distributions. Geometric distributions can play a significant role in the impedance response of electrochemical systems, and these distributions can lead to CPE behavior.

Research paper thumbnail of Reactivity of Cr(CO)6 in atmospheric pressure CVD processes for the growth of various metallurgical coatings

HAL (Le Centre pour la Communication Scientifique Directe), 2007

Metalorganic precursors allow a significant decrease of the deposition temperature in CVD process... more Metalorganic precursors allow a significant decrease of the deposition temperature in CVD processes. When they are employed under atmospheric pressure and using direct liquid injection delivery systems, new processes can be developed for the growth of metallurgical coatings. However, even for a single precursor the great variety of reactive gas phase leads to various coatings with different properties. Original nanocrystalline CrC x O y and CrN x O y films were deposited in a laminar flow reactor by MOCVD and DLICVD using Cr(CO) 6 as molecular precursor in the temperature range 285-450 °C. Pyrolysis was carried out in different ambient including N 2 , H 2 , NH 3 , THF, and toluene. The influence of the various atmosphere on the composition, structure and, consequently, mechanical properties and corrosion behavior of these coatings is discussed.

Research paper thumbnail of Comparison between the influence of applied electrode and electrolyte temperatures on porous anodizing of aluminium

Electrochimica Acta, Apr 1, 2010

A new approach for studying the effect of temperature on anodic oxide growth on aluminium is pres... more A new approach for studying the effect of temperature on anodic oxide growth on aluminium is presented in this paper. Using an in-house developed electrode holder, anodizing is performed under conditions of applied and controlled electrode temperature. The influence of temperature on the process is evaluated by experiments in a broad temperature range for both the electrode and the electrolyte temperature. The electrochemical behaviour of the aluminium electrodes is demonstrated to be more susceptible to variations of the electrode temperature than to variations of the electrolyte temperature. Concerning the morphology of the anodic film it is shown that by cooling the electrode a normal oxide layer could be grown at high electrolyte temperatures, whereas anodizing in a cool electrolyte at high electrode temperature results in a collapsed porous structure at the oxide surface. Furthermore, the electrode temperature affects the formation ratio of the oxide to a larger extent than the electrolyte temperature, indicating its important influence even on the level of the ionic conductivity during anodic oxide growth. All observations indicate that merely considering the electrolyte temperature upon studying the influence of temperature on the process is not sufficient; the electrode temperature is much more determining.

Research paper thumbnail of Study of copper corrosion using Localized impedance spectroscopy andAuger Spectroscopy

Finds and Results from the Swedish Cyprus Expedition: A Gender Perspective at the Medelhavsmuseet, 2006

Research paper thumbnail of Chromium-free conversion coatings based on inorganic salts (Zr/Ti/Mn/Mo) for aluminum alloys used in aircraft applications

Applied Surface Science, 2015

Novel chromium-free conversion coatings based on Zr/Ti/Mn/Mo compounds were developed at a pilot ... more Novel chromium-free conversion coatings based on Zr/Ti/Mn/Mo compounds were developed at a pilot scale to improve the corrosion resistance of the AA2024-T3 and AA7075-T6 aluminum alloys for aircraft applications. The influence of the presence of Zr and Ti in the Zr/Ti/Mn/Mo conversion bath´s formulation on the corrosion resistance of the coated alloys was investigated. The corrosion resistance provided by the conversion coatings was evaluated by salt spray exposure and potentiodynamic sweeps. Optical and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS) and atomic force microscopy (AFM) operating in the Kelvin probe mode (SKPFM) were used to provide microstructural information of the coated samples that achieved the best results in the corrosion tests. The salt spray test evidenced the higher corrosion resistance of the coated samples compared to the bare surfaces for both alloys. The potentiodynamic tests showed that the corrosion current density decreased for coated AA7075-T6 and AA2024-T3 alloys, which indicated an obvious improvement of the corrosion resistance with all the processes for both alloys. Although the corrosion resistance of the coated samples appeared to be higher for the alloy AA7075-T6 than for the alloy AA2024-T3, both alloys achieved the best corrosion protection with the coatings deposited from conversion bath formulations containing no titanium salts. The microscopy analysis on the coated AA7075-T6 samples revealed that a local deposition of Zr compounds and, possibly, an oxidation process occurred in the vicinity of the alloy´s intermetallic particles. The amount of the Zr deposits at these locations increased with coating´s formulations without Ti, which provided the best corrosion resistance. The Cr-free conversion coatings developed in this study for the AA7075-T6 and AA2024-T3 alloys do not meet yet the strict requirements of the aircraft industry. However, they significantly improved the corrosion performance with respect to the bare alloys and could be a good starting point for further studies and optimization.

Research paper thumbnail of Odd random phase multisine EIS for organic coating analysis

Progress in Organic Coatings, Oct 1, 2010

ABSTRACT In this paper the different steps involved in an integrated methodology to measure, anal... more ABSTRACT In this paper the different steps involved in an integrated methodology to measure, analyze and model electrochemical systems in a correct and reliable way are shown for Al-rich metallic coated steel with an additional organic coating. This methodology is based on the use of an odd random phase multisine excitation signal and was proposed by our group previously. The use of this multisine excitation signal decreases the measurement time. Moreover, it allows to perform a rigourous data-analysis and to quantify the signal-to-noise ratio, the level of non-linear and non-stationary behaviour. It was shown that by using this technique the optimal measurement conditions can be chosen based on a trade-off between signal-to-noise ratio and non-linear behaviour. Moreover, in the modeling procedure the noise, non-linearities or non-stationarities can be taken into account. The methodology allows a statistical evaluation of the proposed model for the coated metal, indicating whether model errors are still present or not.

Research paper thumbnail of Highly Sensitive Undersea Corrosion Monitoring System

Research paper thumbnail of Delaminated areas beneath organic coating: a local electrochemical impedance approach, Corros

Local electrochemical impedance mapping was used to investigate delamination phenomena at the ste... more Local electrochemical impedance mapping was used to investigate delamination phenomena at the steel/epoxy-vinyl primer interface. The delamination occurred from an artificial defect (cutter scribing) and from ageing in a salt spray chamber. The samples were taken from the salt spray chamber after 20, 30 and 50 days of exposure. To observe delamination after ageing, the corrosion product layers were removed by a cathodic polarization at −1.5 V/SCE for 4 h. A non-aged reference sample was tested for comparison. Mapping was performed at 5 kHz. Initiation and propagation of the delamination were clearly observed. The delaminated surface areas measured by visual observations after the removal of the coating were lower than those determined by local electrochemical impedance mapping. The delamination mechanisms were discussed with reference to literature data.

Research paper thumbnail of Odd random phase multisine EIS for organic coating analysis

Progress in Organic Coatings, 2010

ABSTRACT In this paper the different steps involved in an integrated methodology to measure, anal... more ABSTRACT In this paper the different steps involved in an integrated methodology to measure, analyze and model electrochemical systems in a correct and reliable way are shown for Al-rich metallic coated steel with an additional organic coating. This methodology is based on the use of an odd random phase multisine excitation signal and was proposed by our group previously. The use of this multisine excitation signal decreases the measurement time. Moreover, it allows to perform a rigourous data-analysis and to quantify the signal-to-noise ratio, the level of non-linear and non-stationary behaviour. It was shown that by using this technique the optimal measurement conditions can be chosen based on a trade-off between signal-to-noise ratio and non-linear behaviour. Moreover, in the modeling procedure the noise, non-linearities or non-stationarities can be taken into account. The methodology allows a statistical evaluation of the proposed model for the coated metal, indicating whether model errors are still present or not.

Research paper thumbnail of Microstructural and electrochemical investigations of the corrosion of 2024-T3 Al alloy in low concentration chloride medium

Research paper thumbnail of Spectroscopie d'impédance electrochimique locale : caracterisation de la de lamination des peintures et de la corrosion des alliages Al-Cu

Ce travail est consacre a l'etude, au developpement et a differentes applications de la spect... more Ce travail est consacre a l'etude, au developpement et a differentes applications de la spectroscopie d'impedance electrochimique locale ou SIEL. La premiere partie de ce memoire se focalise sur la description et le developpement de la SIEL tant d'un point de vue experimental que theorique. La seconde partie presente trois applications differentes dans lesquelles la SIEL apporte des informations determinantes. La premiere application est consacree a l'etude du CPE (constant phase element). Cet element, bien que regulierement utilise dans l'interpretation des diagrammes d'impedance electrochimique, garde une signification physique vague. Les mesures de SIEL ont montre que le CPE pouvait etre interprete comme une distribution locale de resistances et de capacites en 2 ou 3 dimensions. Les etudes suivantes se rapportent au domaine de la corrosion et de la protection des materiaux. L'une d'entre elle est axee sur l'observation de la delamination se pr...

Research paper thumbnail of Reactivity of Cr(CO)6 in atmospheric pressure CVD processes for the growth of various metallurgical coatings

Metalorganic precursors allow a significant decrease of the deposition temperature in CVD process... more Metalorganic precursors allow a significant decrease of the deposition temperature in CVD processes. When they are employed under atmospheric pressure and using direct liquid injection delivery systems, new processes can be developed for the growth of metallurgical coat- ings. However, even for a single precursor the great variety of reactive gas phase leads to various coatings with different properties. Original nanocrystalline CrC x O y and CrN x O y films were depos- ited in a laminar flow reactor by MOCVD and DLICVD using Cr(CO) 6 as molecular precursor in the temperature range 285-450 °C. Pyrolysis was carried out in different ambient including N 2 , H 2 , NH 3 , THF, and toluene. The influence of the various atmosphere on the composition, structure and, consequently, mechanical properties and corrosion behavior of these coatings is discussed.

Research paper thumbnail of Spectroscopie d'impédance electrochimique locale : caracterisation de la de lamination des peintures et de la corrosion des alliages Al-Cu

En préambule à ce manuscrit, je souhaite exprimer ma reconnaissance et mes remerciements aux pers... more En préambule à ce manuscrit, je souhaite exprimer ma reconnaissance et mes remerciements aux personnes qui m'ont soutenu et aidé durant les années consacrées à la réalisation de ce travail. Dans un premier temps, je remercie monsieur Bernard Tribollet, directeur de recherche CNRS au sein du Laboratoire interface et systèmes électrochimiques (LISE) pour l'aide qu'il m'a apporté dtout au long de ce travail, et aussi pour avoir accepter de présider mon jury de thèse. Je tiens à remercier sincèrement monsieur Sébastien Touzain, maître de conférence à l'Uni

Research paper thumbnail of Investigation of the self-healing properties of shape memory polyurethane coatings with the ‘odd random phase multisine’ electrochemical impedance spectroscopy

Electrochimica Acta, Aug 1, 2010

This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit:

Research paper thumbnail of Galvanic Coupling Between Pure Copper and Pure Aluminum

Journal of The Electrochemical Society, 2008

Research paper thumbnail of Comparison of local electrochemical impedance measurements derived from bi-electrode and microcapillary techniques

Electrochimica Acta, Oct 1, 2009

In the present paper, local electrochemical impedance spectra were obtained on a 316L stainless s... more In the present paper, local electrochemical impedance spectra were obtained on a 316L stainless steel from two configurations: a dual microelectrode (bi-electrode) and microcapillaries. With the bi-electrode, the local impedance measurements were made from the ratio of the applied voltage to the local current density calculated from the application of the ohm's law. With the use of microelectrochemical cells, the specimen surface area in contact with the electrolyte is limited by the use of glass microcapillaries and the local impedance was defined from the ratio of the local potential to the local current restricted to the analysed surface area. Differences and similarities observed in local impedance spectra obtained with the two configurations were described.

Research paper thumbnail of Determination of the sensitized zone extension in welded AISI 304 stainless steel using non-destructive electrochemical techniques

Corrosion Science, Apr 1, 2008

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Research paper thumbnail of Contribution to a better understanding of different behaviour patterns observed with organic coatings evaluated by electrochemical impedance spectroscopy

Corrosion Science, Jun 1, 2009

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Research paper thumbnail of Delaminated areas beneath organic coating: A local electrochemical impedance approach

Corrosion Science, Jul 1, 2006

Local electrochemical impedance mapping was used to investigate delamination phenomena at the ste... more Local electrochemical impedance mapping was used to investigate delamination phenomena at the steel/epoxy-vinyl primer interface. The delamination occurred from an artificial defect (cutter scribing) and from ageing in a salt spray chamber. The samples were taken from the salt spray chamber after 20, 30 and 50 days of exposure. To observe delamination after ageing, the corrosion product layers were removed by a cathodic polarization at −1.5 V/SCE for 4 h. A non-aged reference sample was tested for comparison. Mapping was performed at 5 kHz. Initiation and propagation of the delamination were clearly observed. The delaminated surface areas measured by visual observations after the removal of the coating were lower than those determined by local electrochemical impedance mapping. The delamination mechanisms were discussed with reference to literature data.

Research paper thumbnail of Corrosion protection of carbon steel by an epoxy resin containing organically modified clay

Surface & Coatings Technology, May 1, 2007

This study focusses on the use of montmorillonite clay (MMT) treated with an organic compound (am... more This study focusses on the use of montmorillonite clay (MMT) treated with an organic compound (aminotrimethylphosphonic acid (ATMP)) and dispersed in an epoxy resin to improve corrosion protection of carbon steel. X-ray diffraction was performed to verify that the individual silicate layers were separated and dispersed in the epoxy resin. Corrosion resistance of the coated steel was evaluated by electrochemical impedance spectroscopy (EIS) and local electrochemical impedance spectroscopy (LEIS). Three systems were tested: the epoxy clear-coat, the epoxy resin containing 2 wt.% clay and the epoxy resin containing 2 wt.% clay modified by ATMP (ATMP-modified clay). From conventional EIS, it was shown that the incorporation of clay or ATMP-modified clay in the epoxy matrix significantly improved the barrier properties of the coating. The corrosion resistance of the carbon steel coated by the epoxy resin containing ATMP-modified clay was higher than that obtained for the system containing non-treated clay. Local electrochemical measurements performed on scratched samples revealed the inhibitive role of ATMP at the carbon steel/coating interface.

Research paper thumbnail of CPE analysis by local electrochemical impedance spectroscopy

Electrochimica Acta, 2006

Constant-phase elements (CPE) are used extensively in equivalent electrical circuits for fitting ... more Constant-phase elements (CPE) are used extensively in equivalent electrical circuits for fitting of experimental impedance data. The CPE behavior is generally attributed to distributed surface reactivity, surface inhomogeneity, roughness or fractal geometry, electrode porosity, and to current and potential distributions associated with electrode geometry. In this work, different electrochemical systems showing the CPE dependence in the high-frequency range for the overall impedance were considered. Local electrochemical impedance spectroscopy was found to provide a good means for assessing the influence of local variations on the CPE behavior seen in global impedance measurements. A separation between 2D and 3D distributions could be easily observed. In the case of a 2D distribution (AZ91 Mg alloy), the origin of the CPE behavior was the distribution of high-frequency resistance associated with the geometry of the disk electrode; whereas, the capacitance was independent of position. In the case of the aluminium electrode, the CPE behavior could be attributed to a combination of 3D and 2D distributions. Geometric distributions can play a significant role in the impedance response of electrochemical systems, and these distributions can lead to CPE behavior.

Research paper thumbnail of Reactivity of Cr(CO)6 in atmospheric pressure CVD processes for the growth of various metallurgical coatings

HAL (Le Centre pour la Communication Scientifique Directe), 2007

Metalorganic precursors allow a significant decrease of the deposition temperature in CVD process... more Metalorganic precursors allow a significant decrease of the deposition temperature in CVD processes. When they are employed under atmospheric pressure and using direct liquid injection delivery systems, new processes can be developed for the growth of metallurgical coatings. However, even for a single precursor the great variety of reactive gas phase leads to various coatings with different properties. Original nanocrystalline CrC x O y and CrN x O y films were deposited in a laminar flow reactor by MOCVD and DLICVD using Cr(CO) 6 as molecular precursor in the temperature range 285-450 °C. Pyrolysis was carried out in different ambient including N 2 , H 2 , NH 3 , THF, and toluene. The influence of the various atmosphere on the composition, structure and, consequently, mechanical properties and corrosion behavior of these coatings is discussed.

Research paper thumbnail of Comparison between the influence of applied electrode and electrolyte temperatures on porous anodizing of aluminium

Electrochimica Acta, Apr 1, 2010

A new approach for studying the effect of temperature on anodic oxide growth on aluminium is pres... more A new approach for studying the effect of temperature on anodic oxide growth on aluminium is presented in this paper. Using an in-house developed electrode holder, anodizing is performed under conditions of applied and controlled electrode temperature. The influence of temperature on the process is evaluated by experiments in a broad temperature range for both the electrode and the electrolyte temperature. The electrochemical behaviour of the aluminium electrodes is demonstrated to be more susceptible to variations of the electrode temperature than to variations of the electrolyte temperature. Concerning the morphology of the anodic film it is shown that by cooling the electrode a normal oxide layer could be grown at high electrolyte temperatures, whereas anodizing in a cool electrolyte at high electrode temperature results in a collapsed porous structure at the oxide surface. Furthermore, the electrode temperature affects the formation ratio of the oxide to a larger extent than the electrolyte temperature, indicating its important influence even on the level of the ionic conductivity during anodic oxide growth. All observations indicate that merely considering the electrolyte temperature upon studying the influence of temperature on the process is not sufficient; the electrode temperature is much more determining.

Research paper thumbnail of Study of copper corrosion using Localized impedance spectroscopy andAuger Spectroscopy

Finds and Results from the Swedish Cyprus Expedition: A Gender Perspective at the Medelhavsmuseet, 2006

Research paper thumbnail of Chromium-free conversion coatings based on inorganic salts (Zr/Ti/Mn/Mo) for aluminum alloys used in aircraft applications

Applied Surface Science, 2015

Novel chromium-free conversion coatings based on Zr/Ti/Mn/Mo compounds were developed at a pilot ... more Novel chromium-free conversion coatings based on Zr/Ti/Mn/Mo compounds were developed at a pilot scale to improve the corrosion resistance of the AA2024-T3 and AA7075-T6 aluminum alloys for aircraft applications. The influence of the presence of Zr and Ti in the Zr/Ti/Mn/Mo conversion bath´s formulation on the corrosion resistance of the coated alloys was investigated. The corrosion resistance provided by the conversion coatings was evaluated by salt spray exposure and potentiodynamic sweeps. Optical and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS) and atomic force microscopy (AFM) operating in the Kelvin probe mode (SKPFM) were used to provide microstructural information of the coated samples that achieved the best results in the corrosion tests. The salt spray test evidenced the higher corrosion resistance of the coated samples compared to the bare surfaces for both alloys. The potentiodynamic tests showed that the corrosion current density decreased for coated AA7075-T6 and AA2024-T3 alloys, which indicated an obvious improvement of the corrosion resistance with all the processes for both alloys. Although the corrosion resistance of the coated samples appeared to be higher for the alloy AA7075-T6 than for the alloy AA2024-T3, both alloys achieved the best corrosion protection with the coatings deposited from conversion bath formulations containing no titanium salts. The microscopy analysis on the coated AA7075-T6 samples revealed that a local deposition of Zr compounds and, possibly, an oxidation process occurred in the vicinity of the alloy´s intermetallic particles. The amount of the Zr deposits at these locations increased with coating´s formulations without Ti, which provided the best corrosion resistance. The Cr-free conversion coatings developed in this study for the AA7075-T6 and AA2024-T3 alloys do not meet yet the strict requirements of the aircraft industry. However, they significantly improved the corrosion performance with respect to the bare alloys and could be a good starting point for further studies and optimization.

Research paper thumbnail of Odd random phase multisine EIS for organic coating analysis

Progress in Organic Coatings, Oct 1, 2010

ABSTRACT In this paper the different steps involved in an integrated methodology to measure, anal... more ABSTRACT In this paper the different steps involved in an integrated methodology to measure, analyze and model electrochemical systems in a correct and reliable way are shown for Al-rich metallic coated steel with an additional organic coating. This methodology is based on the use of an odd random phase multisine excitation signal and was proposed by our group previously. The use of this multisine excitation signal decreases the measurement time. Moreover, it allows to perform a rigourous data-analysis and to quantify the signal-to-noise ratio, the level of non-linear and non-stationary behaviour. It was shown that by using this technique the optimal measurement conditions can be chosen based on a trade-off between signal-to-noise ratio and non-linear behaviour. Moreover, in the modeling procedure the noise, non-linearities or non-stationarities can be taken into account. The methodology allows a statistical evaluation of the proposed model for the coated metal, indicating whether model errors are still present or not.

Research paper thumbnail of Highly Sensitive Undersea Corrosion Monitoring System

Research paper thumbnail of Delaminated areas beneath organic coating: a local electrochemical impedance approach, Corros

Local electrochemical impedance mapping was used to investigate delamination phenomena at the ste... more Local electrochemical impedance mapping was used to investigate delamination phenomena at the steel/epoxy-vinyl primer interface. The delamination occurred from an artificial defect (cutter scribing) and from ageing in a salt spray chamber. The samples were taken from the salt spray chamber after 20, 30 and 50 days of exposure. To observe delamination after ageing, the corrosion product layers were removed by a cathodic polarization at −1.5 V/SCE for 4 h. A non-aged reference sample was tested for comparison. Mapping was performed at 5 kHz. Initiation and propagation of the delamination were clearly observed. The delaminated surface areas measured by visual observations after the removal of the coating were lower than those determined by local electrochemical impedance mapping. The delamination mechanisms were discussed with reference to literature data.

Research paper thumbnail of Odd random phase multisine EIS for organic coating analysis

Progress in Organic Coatings, 2010

ABSTRACT In this paper the different steps involved in an integrated methodology to measure, anal... more ABSTRACT In this paper the different steps involved in an integrated methodology to measure, analyze and model electrochemical systems in a correct and reliable way are shown for Al-rich metallic coated steel with an additional organic coating. This methodology is based on the use of an odd random phase multisine excitation signal and was proposed by our group previously. The use of this multisine excitation signal decreases the measurement time. Moreover, it allows to perform a rigourous data-analysis and to quantify the signal-to-noise ratio, the level of non-linear and non-stationary behaviour. It was shown that by using this technique the optimal measurement conditions can be chosen based on a trade-off between signal-to-noise ratio and non-linear behaviour. Moreover, in the modeling procedure the noise, non-linearities or non-stationarities can be taken into account. The methodology allows a statistical evaluation of the proposed model for the coated metal, indicating whether model errors are still present or not.

Research paper thumbnail of Microstructural and electrochemical investigations of the corrosion of 2024-T3 Al alloy in low concentration chloride medium

Research paper thumbnail of Spectroscopie d'impédance electrochimique locale : caracterisation de la de lamination des peintures et de la corrosion des alliages Al-Cu

Ce travail est consacre a l'etude, au developpement et a differentes applications de la spect... more Ce travail est consacre a l'etude, au developpement et a differentes applications de la spectroscopie d'impedance electrochimique locale ou SIEL. La premiere partie de ce memoire se focalise sur la description et le developpement de la SIEL tant d'un point de vue experimental que theorique. La seconde partie presente trois applications differentes dans lesquelles la SIEL apporte des informations determinantes. La premiere application est consacree a l'etude du CPE (constant phase element). Cet element, bien que regulierement utilise dans l'interpretation des diagrammes d'impedance electrochimique, garde une signification physique vague. Les mesures de SIEL ont montre que le CPE pouvait etre interprete comme une distribution locale de resistances et de capacites en 2 ou 3 dimensions. Les etudes suivantes se rapportent au domaine de la corrosion et de la protection des materiaux. L'une d'entre elle est axee sur l'observation de la delamination se pr...

Research paper thumbnail of Reactivity of Cr(CO)6 in atmospheric pressure CVD processes for the growth of various metallurgical coatings

Metalorganic precursors allow a significant decrease of the deposition temperature in CVD process... more Metalorganic precursors allow a significant decrease of the deposition temperature in CVD processes. When they are employed under atmospheric pressure and using direct liquid injection delivery systems, new processes can be developed for the growth of metallurgical coat- ings. However, even for a single precursor the great variety of reactive gas phase leads to various coatings with different properties. Original nanocrystalline CrC x O y and CrN x O y films were depos- ited in a laminar flow reactor by MOCVD and DLICVD using Cr(CO) 6 as molecular precursor in the temperature range 285-450 °C. Pyrolysis was carried out in different ambient including N 2 , H 2 , NH 3 , THF, and toluene. The influence of the various atmosphere on the composition, structure and, consequently, mechanical properties and corrosion behavior of these coatings is discussed.