Pd–H and Ni–H phase diagrams using cluster variation method and Monte Carlo simulation

ABSTRACT

This work focuses on interstitial solid solutions of hydrogen in the face-centred cubic (fcc) host lattice of palladium and nickel, using a first-principles based approach. Cluster Variation Method (CVM) and Monte Carlo simulation algorithms were especially designed, allowing a coupled use of both techniques, to study hydrogen–vacancy interactions inside an fcc metallic host lattice. First-principles calculations provided the H–Vac interaction energies by structure inversion method. The phase diagrams and thermodynamic properties were computed using only theoretical inputs. The mechanisms leading to the formation of the miscibility gaps observed for both Pd–H and Ni–H systems and the hydrogen ordering on palladium interstitial lattice were reproduced without any empirical term.

KEYWORDS:

• Metal hydrides
• computer modelling and simulation
• miscibility gap

PACS CLASSIFICATION:

• 63.20.dk 88.30.R- 88.30.rd 88.30.G- 65.40.gd 07.05.Tp61.43.Bn 64.75.Nx

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Jean-Claude Crivello http://orcid.org/0000-0002-4849-2556

Jean-Marc Joubert http://orcid.org/0000-0001-7266-1850

Additional information

Funding

This work has benefited from a French government grant managed by Agence nationale de la recherch (ANR) within the framework of the national program Investments for the Future ANR-11-LABX-022-01. DFT calculations were performed using High Performance Computing (HPC) resources from GENCI-CINES (Grant 2018-96175). We thank Pr Tetsuo Mohri from IMR, Tohoku University who provided insight that greatly assisted the research. Ying Chen and Arkapol Saengdeejing are also acknowledged to have initiated the CEM work.