Papers by Author: Christian Coddet

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Authors: Sandrine Coste, Ghislaine Bertrand, Christian Coddet, Eric Gaffet, Horst Hahn, H. Sieger, M.A. Rodriguez, Cathy Meunier, Serge Vives
Abstract: Superior properties of nanostructured Al2O3 based materials, such as higher hardness and fracture toughness, have been evidenced. In order to optimize their manufacturing, the mechanical activation of the starting powders (Al2O3-TiO2 and Al2O3-ZrO2) was studied. In the present work, Al2O3 powders blended with 13wt% and 44wt% of titania or 20wt% and 80wt% of yttria partially stabilized zirconia have been high-energy ball-milled using a planetary mill, P4 (Fritsch) with steel vials and balls. The effect of the milling time and operating parameters, such as shock energy and friction to total energy ratio, on the powder structural and microstructural evolutions has been determined by SEM, XRD and BET. The transformation of the metastable anatase TiO2 phase into the high pressure TiO2 II phase and rutile phase was evidenced, simultaneously to the decrease of the alumina crystallite size, in the Al2O3-TiO2 system. In the Al2O3-ZrO2 system, the transformation of the monoclinic phase and the decrease of the alumina and tetragonal zirconia crystallite size have been observed.
Authors: B. Normand, W. Herbin, O. Landemarre, Christian Coddet, J. Pagetti
Authors: Filofteia Laura Toma, Ghislaine Bertrand, Cathy Meunier, Sylvie Begin, Didier Klein, Christian Coddet
Abstract: This paper deals with the elaboration of titanium dioxide coatings, designed for photocatalytic applications, obtained by a non-conventional method of deposition: suspension plasma spraying (SPS). SPS is an alternative of the atmospheric plasma spraying (APS) in which the feedstock material is a suspension of the powder to be sprayed. The method consists in injection and atomization of a slurry (suspension of fine particles in a solvent) in an enthalpic source (plasma). TiO2 P25 powder (Degussa AG) was mechanically dispersed in distilled water and ethanol and injected in Ar-H2 or Ar-H2-He plasma under atmospheric conditions. SEM and XRD were performed to study the microstructure and the crystalline phases of the titania coatings. Photocatalytic efficiency of the elaborated samples was evaluated from the conversion rate of nitrogen oxides. The present results showed that the suspension plasma spraying allows to produce reactive surfaces for the removal of air pollutants, that in the same working conditions, present a higher photocatalytic activity compared to that of the initial raw powders.
Authors: C. Verdy, G. Wolff, Christian Coddet, D. Cornu, J.M. DeMonicault
Authors: Christian Coddet, C. Verdy, L. Dembinski, Thierry Grosdidier, D. Cornu, J.C. García
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