MONTE CARLO SIMULATION OF HYDROGEN ABSORPTION IN PALLADIUM AND PALLADIUM-SILVER ALLOY

The paper presents Monte Carlo simulation of the hydrogen absorption in palladium and palladium-silver alloy of the composition PdxAg1-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 palladium-silver 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.t.% 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.