0000000000007817
AUTHOR
Vincent Fournée
Aging of the surface of an Al-Cr-Fe approximant phase in ambient conditions: Chemical composition and physical properties
ABSTRACTWe have investigated the surface properties of quasicrystalline and approximant phases in the Al-(Cu)-Cr-Fe system upon aging in ambient conditions. We found that some of these properties (like the electrochemical behavior, wetting or friction) slowly evolves with the length of exposure to normal atmospheric conditions, reaching a stable state only after several days. This report essentially focuses on one of these alloys, an Al65Cr27Fe8 approximant phase with g-brass structure. In a first part, we describe the effect of aging on the electrochemical behavior of this alloy and we propose an interpretation based on a simple electrical model of the oxidized surface. In a second part, w…
Chemical surface ageing in ambient conditions of an Al–Fe–Cr approximant phase.
International audience; The γ -Al65Cr27Fe8 phase is a complex metallic alloy with interesting electrochemical properties. Here we present a detailed study of the surface ageing of this alloy when exposed to ambient conditions for a long time. A combination of x-ray reflectivity, photoemission spectroscopy and secondary neutral mass spectroscopy measurements is used to provide a model of the modification of the surface structure and its composition as functions of ageing time. The near surface structure is described by the stacking of three layers. The first layer on top of the substrate corresponds to a mixed metal oxide and is amorphous. The intermediate layer consists of pure aluminum oxy…