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Article Dans Une Revue Annales de Chimie - Science des Matériaux Année : 2006

Influence of Al on the growth and adherence of NiO layers on nickel-base alloys

Résumé

The objective of this work was to study the influence of low aluminium contents (0.5% by weight) on the growth and the adherence of layers of NiO on polycrystals of nickel. This study was carried out between 700 and 1200 degrees C under P-O2=1 atm. The sinters of Ni and of (Ni-0.5%Al) have very similar densities (96.0 +/- 0.5%) of the theoretical density) and a similar microstructure, which makes it possible to better analyse the specific role of Al on their oxidation resistance. Above 900 degrees C, the addition of aluminium to nickel generates an increase in the speed of oxidation. However, the kinetics remains always parabolic. The oxide formed on the surface of alloys (Ni-0.5%Al) has a duplex structure. In the vicinity of the metal/oxide interface, the layer is porous, not very adherent with the metal and consists of the two phases NiO and NiAl2O4. As a consequence of the process of kinetic decomposition which takes place in the layer of corrosion, the enrichment in Al in the vicinity of the metal/oxide interface was attributed to the difference in diffusivity of the cations, with : D-Al
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Dates et versions

hal-00133254 , version 1 (24-02-2007)

Identifiants

  • HAL Id : hal-00133254 , version 1

Citer

Nacer Halem, Georgette Petot-Ervas. Influence of Al on the growth and adherence of NiO layers on nickel-base alloys. Annales de Chimie - Science des Matériaux, 2006, 31 (2), pp.197-211. ⟨hal-00133254⟩
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