Dresden 2009 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 42: Poster Session II (Nanostructures at surfaces: arrays; Nanostructures at surfaces: Dots, particles, clusters; Nanostructures at surfaces: Other; Nanostructures at surfaces: Wires, tubes; Metal substrates: Adsorption of O and/or H; Metal substrates: Clean surfaces; Metal substrates: Adsorption of organic/bio moledules; Metal substrates: Solid-liquid interfaces; Metal substrates: Adsorption of inorganic molecules; Metal substrates: Epitaxy and growth; Heterogeneous catalysis; Surface chemical reactions; Ab-initio approaches to excitations in condensed matter; Organic, polymeric, biomolecular films– also with adsorbates; Particles and clusters)
O 42.76: Poster
Mittwoch, 25. März 2009, 17:45–20:30, P2
Growth of ultrathin well-ordered Ni-Al alloyed layers on Ni(111) : a Grazing Incidence X-ray Diffraction study — •Séverine Le Moal1, Geoffroy Prévot2, Didier Schmaus2, Rémi Lazzari2, and Bernard Croset2 — 1Institute of Physical and Theoretical Chemistry, University of Bonn, Wegelerstr. 12, D-53115 Bonn, Germany — 2Institut des NanoSciences de Paris, Universités Paris 6 et Paris 7, CNRS, 140 rue de Lourmel, F-75015 Paris, France
Ni-Al alloys are of great technological interest because of their remarkable mechanical and thermal properties. They are also resistant to corrosion due to the formation at their surface of a passive ultrathin film of aluminum oxide that acts as a diffusion barrier. Previously, we reported the epitaxial growth of NiAl and Ni3Al films on a Ni(111) single crystal [Le Pévédic et al, Surf. Sci. 600 (2006) 565 and Surf. Sci. 601 (2007) 395]. We recently studied their structure and the kinetics of formation by Grazing Incidence X-ray Diffraction (ESRF, ID03). Starting from an initial Al deposit, the growth and the structural and chemical ordering of the Ni3Al and NiAl layers are followed upon annealing. Disordered NiAl already forms at room temperature. In the 573-673 K temperature range the thickness of the NiAl layer increases and chemical ordering takes place. Once NiAl has grown up to the surface, ordered Ni3Al starts to form. Simultaneously, the diffraction signal of NiAl decreases and characteristic diffraction spots of Ni3Al appear and get sharper. The Ni3Al layer is stable up to 773 K. The lattice constants of the films were measured throughout growth and annealing time.