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Science et ingénierie des matériaux et des procédés

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Surfaces, Interfaces, Reactivity (SIR)

The scientific subjects of our research group are focused on surface and interfaces, in the fields of phycical chemistry and mechanic, with an effort on the possibility of coupling between them.
The concept of material life time often underlies research, especially involving materials for energy (nuclear, biomass, fuel cells).
In each study, the understanding of phenomena is based on an innovative experimental approach if possible (micro-photoelectrochemistry, acoustic emission, micro-mechanical tests) with the help of well-proven thermodynamic databases (Factsage) and modeling tools (Comsol, Abaqus, Castem).
Group skills are varied, but we can emphasize our excellent expertise in surface physical chemistry, kinetics of heterogeneous processes, adhesion.
Many of the group work is done in collaboration with industry, metallurgical, oil, nuclear, electronics...
Three main themes appear in the observation of research today

News


Last July was organized in Bangkok, by Prof. Somrerk Chandra Ambhorn (on the left), the Prof. Alain Galerie (on the right) Symposium. This event took place in the King Mongkut University of North Bangkok (KMUTNB) and brought together experts in the field of High Temperature Oxidation. 


Alexis Faure, doctorant au SIMaP (2014-2017) est un des deux lauréats du prix de thèse du CSMA 2017 (Computational Structural Mechanics Associtation), décerné à la suite du colloque bi-annuel de l’association qui s’est tenu en mai dernier. Alexis a mené son doctorat au laboratoire sous la direction de R. Estevez (SIR), G. Parry (PM) et dans le cadre d’une collaboration proche avec G. Michailidis, post-doc au sein de SIR, tout en nouant des collaborations fructueuses avec la communauté de mathématiques appliquées de Grenoble (C. Dapogny au LJK) et de Paris (G. Allaire, CMAP Ecole polytechnique), ainsi qu’avec (bien entendu) Y. Bréchet. Son doctorat a été financé par le labex CEMAM, son manuscrit intitulé « Optimisation de forme de matériaux et structures architecturés par la méthode des lignes de niveaux avec prise en compte des interfaces graduées » a donné lieu à cinq publications internationales, abordant des sujets d’actualité comme la prise en compte de multimatériaux en optimisation topologiques, la prise en compte de contraintes géométriques ou de fabrication dans le processus de fabrication.






The prize for the best senior poster was awarded to Ass. Prof. Laurence Latu-Romain during the Gordon Research Conference on the High Temperature Corrosion held at New London (NH, USA), last july. This conference, one of the most well known in our community, is organized every two years.
 

Duplex n- and p-type chromia grown on pure chromium: a photoelectrochemical and microscopic study

L. Latu-Romain*, Y. Parsa*, S. Mathieu**, M. Vilasi*, M. Ollivier*, A. Galerie*, Y. Wouters*
*Univ. Grenoble Alpes, CNRS, SIMAP, F-38000 Grenoble, France
**IJL, University of Lorraine, France

Chromia grown on pure chromium at 900 °C for 30 minutes at an oxygen partial pressure p(O2) of 10-12 atm has been characterized using photoelectrochemical and electron microscopy techniques. This study reveals a duplex scale: n-chromia with equiaxis morphology in the internal part (~ 650 nm thick) and p-chromia with columnar morphology in the external part (~ 900 nm thick) (Fig 1a & 1b). Grain orientation maps have also revealed the presence of a c-oriented chromia layer at the interface between the n- and the p-subscales. This (red) <0001> textured layer has been identified as the first-grown chromia layer. Knowing the type of semiconduction from photoelectrochemical characterization and the growth direction from TEM techniques, major point defects could have been identified in the internal and external subscales. It means that internal n-equiaxis chromia is growing by anionic transport governed by oxygen vacancy diffusion whereas external p-columnar chromia layer is growing outwards and is controlled by chromium vacancy diffusion. In order to elucidate how the predominant defects can change from oxygen vacancy to chromium vacancy with increasing of oxygen partial pressure in the Cr2O3 scale, an original Brouwer diagram has been proposed (Fig 1c). 

Fig. 1 (a) (b) ASTAR grain orientation maps (see colour codes on the left) of Cr2O3 grown on pure Cr at a p(O2) of 10-12 atm at 900 °C during 30 minutes recorded with a probe size of 1 nm and a step size of 3 nm, (a) and (b) representing two different areas recorded along the thin lamella. (c) Brouwer diagram of Cr2O3 based on a Schottky disorder.

Contact: L. Latu-Romain & Y. Wouters

Rédigé par Yves Wouters

mise à jour le 10 décembre 2018

Univ. Grenoble Alpes