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Keywords:

surface, segregation, Pd-Ni alloy, modeling, Science & Technology, Physical Sciences, Technology, Chemistry, Physical, Materials Science, Coatings & Films, Physics, Applied, Physics, Condensed Matter, Chemistry, Materials Science, Physics, Monte Carlo simulations, embedded atom method, surface segregation, surface thermodynamics, nickel, palladium, SEGREGATION PROFILE, NI50PD50(100), HYDROGENATION, REACTIVITY, Applied Physics

Abstract:

Monte Carlo (MC) simulations with the embedded atom method (EAM) are set up to investigate the segregation at Pd x Ni 100-x (1 0 0), (1 1 0) and (1 1 1) surfaces (1 ≤ x ≤ 50) as a function of temperature. Simulations in the temperature range from 600 to 1000 K show a pronounced segregation of Pd for all compositions, in agreement with the lower surface energy of Pd. At higher temperatures, the Pd segregation is less pronounced (exothermic segregation in disordered alloys). For Pd-richer alloys, the tendency for segregation is attenuated as the strain energy becomes less important. Furthermore, the depth profiles differ markedly for diluted or Pd-rich alloys. Special attention is paid to the different driving forces explaining this segregation behaviour. © 2003 Elsevier Science B.V. All rights reserved.