UFR de Physique

Propositions de stages en laboratoire -- M2

Les offres sont actualisées en mai. Par exemple, les offres de stages pour l'année universitaire 2015-2016 seront mises en place en mai 2015, les offres de stages pour l'année universitaire 2016-2017 seront mises en place pour en mai 2016, etc.

MIN_Hydrothermal alteration of amorphous silicate. Experiments and transmission electron microscopy analysis.

  • Option Structure et Propriétés de la Matière Condensée, Générique du parcours Structure et Propriétés de la Matière Condensée
  • Laboratoire: Unité Matériaux et Transformations (UMET)
  • Responsable du stage: LE GUILLOU Corentin (corentin.le-guillou@univ-lille1.fr, 0320434913)
  • Mots clés:

Meteorites come from asteroids which formed at the same time as our solar system, 4.5 billions years ago. They thus contain the oldest and most primitive materials that can be studied in the laboratory. Amorphous silicates are a major component of these objects (together with other silicates, metals, carbonates and organic matter). However, water is also accreted within asteroids, reacts with the various materials and modifies their chemical and mineralogical compositions. During these hydrothermal episodes, amorphous silicates are hydrated and oxidized, under conditions which are not well understood. In order to constrain the temperature, the pH and/or the redox conditions of these alteration events, we propose to carry experiments on analogues materials. The objective of this project is to study the kinetics and chemical mechanisms of the alteration of amorphous silicates. The first step will consist in synthesizing thin films of amorphous silicates and running the conducting the experiments, i.e. reacting the thin film with water in a furnace at different conditions. Then, the reacted products, will be analyzed at the nanometer scale with state-of-the-art electron microscopy. In particular, understanding the physic of the alteration reaction requires to be able to determine the valence of iron, the density as well as the porosity of the hydrated and oxidized layers. This requires the use of specific analytical techniques such as electron energy loss spectroscopy (EELS) or tomography.