Etude du mécanisme de nanostructuration oxydante de ZrAu (application à la synthèse de nanocomposites or-zircone pour microcapteurs de gaz)

L'étude de l'alliage ZrAu a permis de déterminer ses structures cristallines, d'étudier sa cinétique d'oxydation unique sous air et à 25C et d'envisager des perspectives d'applications de type microcapteurs catalytiques. ZrAu est triphasé en température : Pour TC>569C sa structure est une structure de CsCI. Pour 400569C, ZrAu is a CsCI superstructure. For 400<TC<569 and TC<400, it is respectively monoclinic and triclinic evolutions of the first structure. The oxidation phenomenon is an atmospheric type one and its kinetic is linear in time (2 m per day). Resulting gold and monoclinic zirconia nanoparticles are meanly 3-5 nm sized. The nucleation-growth process of gold nanoparticles has been studied. The formation of monoclinic zirconia phase for such weak sizes has been explained by a modification of the Gibbs law. From this unique degradation phenomenon, we consider in the last part its application for the synthesis of nanostructured thin films for catalysis applications.TOULON-BU Centrale (830622101) / SudocSudocFranceF