Self-assembling of atomic vacancies at an oxide/intermetallic alloy interface.
Oxide layers grown on the surface provide an effective way of protecting metallic materials against corrosion for sustainable use in a broad range of applications. However, the growth of cavities at the metal/oxide interface weakens the adherence of the protective layer and can promote its spallation under service conditions, as observed for alumina layers formed by selective oxidation of aluminide intermetallic alloys used in high-temperature applications. Here we show that direct atomic-scale observations of the interface between an ultrathin protective oxide layer (alumina) grown on an intermetallic titanium aluminide substrate (TiAl) can be performed with techniques sensitive to the topmost atomic layers at the surface. Nanocavities resulting from the self-assembling of atomic vacancies injected at the interface by the growth mechanism of the protective oxide are observed for the first time, bringing new insight into the understanding of the fate of injected cavities in oxidation processes.
Maurice
Vincent
V
Laboratoire de Physico-Chimie des Surfaces, ENSCP/CNRS (UMR 7045), Ecole Nationale Supérieure de Chimie de Paris, 11 rue Pierre et Marie Curie, 75231 Paris Cedex 05, France. vincent-maurice@enscp.jussieu.fr <vincent-maurice@enscp.jussieu.fr>
Despert
Guillaume
G
Zanna
Sandrine
S
Bacos
Marie-Pierre
MP
Marcus
Philippe
P
D000537:Aluminum Oxide / Q000737:chemistry; D003343:Corrosion; D004563:Electrochemistry; D008670:Metals / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry
D008670:Metals; D010087:Oxides; D014025:Titanium; D000537:Aluminum Oxide