Papers by Christian Coddet
Surface and Coatings Technology, 2008
Journal of Physics and Chemistry of Solids, 2009
The paper studies the effect of high-velocity oxy-fuel thermal spraying parameters, in particular... more The paper studies the effect of high-velocity oxy-fuel thermal spraying parameters, in particular spray distance and oxygen flow rate, on
coating porosity and magnetic properties of FeSi and FeSiB deposits using the artificial neural network methodology. The magnetic properties
correlated to coating porosity were obtained using an optimized network structure. The predicted results permitted to point out the role of
porosity for varying the coercivity and saturation magnetization and the stability of magnetic properties with respect to the considered spray
parameters.
Electrochimica Acta, 2004
Poly(ether ether ketone) (PEEK) thermally sprayed coatings find more and more applications, and e... more Poly(ether ether ketone) (PEEK) thermally sprayed coatings find more and more applications, and ensure often the protective effect of substrate metals when the coated material is exposed to an aggressive medium. This coating exhibits extremely high impedance, and the impedance measurements of coated specimen were impossible to perform several years ago. Therefore, it was unable to evaluate quantitatively the coating protective performance by an electrochemical impedance method. Such measurements were realized, in this paper, with a recent device, and the impedance behaviour observed was interpreted in terms of dielectric relaxation after extracting the frequency dependent capacitance from the impedance spectra. It was found that the water uptake in PEEK coating is particularly low, ca. 1% and no interaction with absorbed water molecules and polymer matrix was detected. This result verifies therefore exceptionally high performance behaviour of PEEK thermally sprayed coating in an aqueous medium. The impedance measurements may therefore be used to evaluate accurately the corrosion protective effect of such a coating during development for new applications, and also to optimize the deposition conditions.
Revue de Métallurgie, 2004
ABSTRACT
Nanoparticles show novel properties compared to the bulk material of same chemistry. The small si... more Nanoparticles show novel properties compared to the bulk material of same chemistry. The small size is responsible for many changes in the thermo-physical properties. Thus, there was an increasing interest in nanomaterials since the past five years.
Surface and Coatings Technology, 2006
La température d'utilisation importante des SOFC est à l'origine de nombreux problèmes tant au ni... more La température d'utilisation importante des SOFC est à l'origine de nombreux problèmes tant au niveau du choix des matériaux que de la durée de vie des piles. Un point clef dans l'obtention d'une pile fonctionnant à basse température est la production d'un électrolyte dense et mince (typiquement une vingtaine de microns). Dans ce but, le procédé de projection par plasma d'arc soufflé atmosphérique (APS) a été adapté en remplaçant la poudre usuellement injectée dans le plasma par une suspension de fines particules. Des barbotines contenant des particules de zircone yttriée dispersées dans divers solvants et en présence d'un dispersant adapté ont donc été réalisées et injectées dans le plasma. Outre ces différentes formulations de barbotines étudiées, certains paramètres opératoires de projection ont été évalues. Les microstructures ainsi obtenues ont été observées par microscopie électronique. Un effort particulier a été porté sur la détermination de l'effet de la distance de projection, de la cinématique torche-substrat ainsi que de l'intérêt d'une étape dite de refusion, qui consiste a densifier en surface le dépôt par passage de la torche.
Objective : optimize the mechanical properties of nanostructured Al 2 O 3 -TiO 2 coatings manufac... more Objective : optimize the mechanical properties of nanostructured Al 2 O 3 -TiO 2 coatings manufactured through a metastable process: atmospheric plasma spraying of high-energy ball-milled powders Transformation of anatase TiO 2 into TiO 2 II (High pressure phase).
Revista de Chimie -Bucharest- Original Edition-
The protection of metallic surface is commonly done with zinc phosphate in acid aqueous phosphate... more The protection of metallic surface is commonly done with zinc phosphate in acid aqueous phosphate solutions containing zinc ions and phosphoric acid, as well in addition of other metallic ions (nickel, chromium, calcium, niobium etc.), in presence of accelerators as nitrate ions, hydroxylamine sulfate, benzotriazole and others. The present article is a study on the surface structure of zinc phosphated layers used as protection against corrosion.
OPTOELECTRONICS AND ADVANCED MATERIALS-RAPID COMMUNICATIONS
ABSTRACT
... Spray Standards Program with Comment on Those for the Corrosion Protection of Steel and Reinf... more ... Spray Standards Program with Comment on Those for the Corrosion Protection of Steel and Reinforced Concrete 203 RA Sulit, Digital Systems ... Point Bend Tests 303 J. Voy er, F. Gitzhofer, MI Boulos, University of Sherbrooke, Sherbrooke, Québec, Canada J. Dionne, Pratt & ...
Advanced Engineering Materials
The newly designed abradable coatings are usually validated by rig tests, where samples are rubbe... more The newly designed abradable coatings are usually validated by rig tests, where samples are rubbed by the contact of a dummy blade with given running speed and incursion rate, simulating actual working conditions in an aircraft engine. The aim of this work was to develop a model of abradable coating rig tests, allowing extensive studies of the influence of coating properties and test conditions on the thermal behaviour of the system. The proposed model includes several steps implementing different numerical tools. Firstly, a relevant structural description of an abradable coating is obtained from micrographs, using an original image analysis route. FE (Finite Element) calculations based on this description allow then to estimate the coefficients of an anisotropic elastic law of mechanical behaviour. Furthermore, a plasticity law is deduced from a FE simulation of the material HR15Y hardness. These parameters are used as input of a FE simulation of a single blade-to-coating rubbing hit, resulting in calculated stresses and temperatures. Finally a global approach of the complete abradability test, based on the results obtained from the simulation of a single hit and on various assumptions, provides predictions of the blade and coating temperature variations versus time during a complete abradability test.
Chromium nitride coatings have been considered as promising hard coating materials due to their h... more Chromium nitride coatings have been considered as promising hard coating materials due to their high hardness, good wear and corrosion resistance as well as high temperature oxidation resistance. Nickel coatings, on the other hand, are widely used as protective coatings against oxidation and corrosion. The combinations of these two kinds of coatings are expected to develop a new coating, which properly extent the applications in industry especially for protecting stainless steels by reducing thermal expansion mismatch, promoting an enhanced adherence and bonding.
Gas atomization of liquid metal using a De Laval nozzle is one of the most efficient processes in... more Gas atomization of liquid metal using a De Laval nozzle is one of the most efficient processes in terms of powder quality including size and composition criteria and in terms of inert gas consumption used to atomize the liquid metal. However, the comprehension of the involved events is at that time of prime importance to optimize this process and the researches are focused on both experimental and modelling approaches. For example, very few experimental data are available on the liquid metal atomization because of the difficulty to achieve measurements very close to the atomization area. The paper concerns some experimental results obtained with Fe-Al 28% metal spraying. Different techniques (MEB, EDS, RX) were used to characterize the properties of this produced powder. The morphology, the microstructure and the hardness were also analyzed as a function of the diameter of the powder. The evolutions of the powder characteristics during the atomization process were determined as well...
Uploads
Papers by Christian Coddet
coating porosity and magnetic properties of FeSi and FeSiB deposits using the artificial neural network methodology. The magnetic properties
correlated to coating porosity were obtained using an optimized network structure. The predicted results permitted to point out the role of
porosity for varying the coercivity and saturation magnetization and the stability of magnetic properties with respect to the considered spray
parameters.
coating porosity and magnetic properties of FeSi and FeSiB deposits using the artificial neural network methodology. The magnetic properties
correlated to coating porosity were obtained using an optimized network structure. The predicted results permitted to point out the role of
porosity for varying the coercivity and saturation magnetization and the stability of magnetic properties with respect to the considered spray
parameters.