AVS 53rd International Symposium
    Surface Science Monday Sessions
       Session SS1-MoA

Paper SS1-MoA9
Effect of Hydrogen on the Stability of Ti on an Al Surface*

Monday, November 13, 2006, 4:40 pm, Room 2002

Session: Catalysis for the Hydrogen Economy
Presenter: R. Bastasz, Sandia National Laboratories
Authors: R. Bastasz, Sandia National Laboratories
W.P. Ellis, Los Alamos National Laboratory
R. Stumpf, Sandia National Laboratories
J.A. Whaley, Sandia National Laboratories
Correspondent: Click to Email
The thermal stability of Ti atoms evaporated onto an Al(100) surface was studied using the surface-sensitive technique of ion scattering spectroscopy (ISS). Measurements were made in vacuum and in the presence of an atomic deuterium beam directed at the sample. When heated in vacuum, Ti begins to disappear from the surface at substrate temperatures below 100°C and is completely absent at temperatures above 250°C. When a similar measurement is made while the sample is being exposed to a flux of deuterium atoms, the Ti persists on the surface to noticeably higher temperatures. Diffusion coefficients for Ti into Al were obtained from ISS data in both cases at selected substrate temperatures in the range 50-150°C. The activation energy for diffusion of Ti from the Al(100) surface appeared to be altered in the presence of D. The experimental results are interpreted using density functional theory, which indicates that H-Ti interactions stabilize surface Ti. @FootnoteText@ *This work was supported by the US Dept. of Energy under contract DE-AC04-94AL85000.