Monte Carlo Simulation of Hydrogen Absorption in Palladium and Palladium-Silver Alloy

Resumo

The paper presents Monte Carlo simulation of the hydrogen absorption in palladium and palladium-silver alloy of the composition Pd_xAg_1–x (x = 0.7–0.9) at 293–373 K temperature and 0.1 MPa pressure. Hydrogen atoms in palladium lattice locate mostly in octahedral holes in a face-centered cubic unit cell. In palladiumsilver alloy with the increased Ag content, the absorption energy distribution of hydrogen becomes wider. The interatomic Ag–H distance is shorter than Pd–H distance that means that when contacting with Ag atoms, H atoms occupy less stable tetrahedral holes. When the amount of silver in the alloy grows up to 30 аt.% H atoms are more likely to locate in tetrahedral vacancies resulting in the stability decrease of the system with hydrogen dissolved in the bulk of the material.