In-situ surface grain resolved corrosion study of polycrystalline AlMg

The oxide formed on polycrystalline Aluminium-Magnesium (AlMg) alloys has been characterized mostly by techniques that provide grain averaged information of the Al matrix and β-phase (Al3Mg2). Therefore, the effects of phase and grain orientation on the thickness of the passive layer is still not available as well as the effect of the oxide thickness on the corrosion and the near surface structure and composition of the alloy. Here we propose an x-ray reflectivity (XRR) and grazing incidence X-ray diffraction (GIXRD) in-situ corrosion experiment, enabling grain resolved and phase sensitive characterization of the thickness of the oxide layer. To this aim, the oxide layer, formed both in air and during exposure to NaCl solution, will be characterized by using the nanobeam at ID01 to obtain grain and phase resolved XRR and GIXRD maps. These maps will enable us to identify the local changes of the oxide that triggers the onset of corrosion and the detrimental role of the Al3Mg2 β-phase.