HYDROGEN ADSORPTION ON β-TiAl (001) AND Ni/TiAl (001) SURFACES

• DOI: 10.1142/s0218625x14500346
• Publication Date: 2014-03-19T01:36:45Z
• Authors: A. A. KARIM MUBARAK; MAHMOUD ALELAIMI
• Keywords: TiAl, hydrogen, surface energy, LDOS, charge density; 02 engineering and technology; 0210 nano-technology; 7. Clean energy

In this paper, we present first principles calculations of the energetic, electronic and magnetic properties of the variant termination of TiAl (001) and Ni / TiAl (001) surfaces with and without hydrogen atoms. The calculations have been performed within the density functional theory using full-potential linearized augmented plane wave method. The generalized gradient approximation (GGA) is utilized as the exchange-correlation energy. The octahedral site is the stable absorption site of H atom in the β- TiAl system. This absorption reduces the cohesive energy of β- TiAl system due to increase in the lattice constant. The surface energy for both TiAl (001) terminations is calculated. The stable adsorption site of H atoms on the variant termination of TiAl (001) surface is performed. The adsorption energy of hydrogen on Ti is more energetic than that on Al . The adsorption of H atom on both terminations of H / Ni / TiAl (001) is more preferable at the bridge site. The adsorption energies are enhanced on Ni atom due to the contraction between d- Ni bands and TiAl substrate band.