Hydrogen sorption in a vacancy zone of an iron-nickel matrix: a DFT study

G. CANTO; I. SALAZAR-EHUAN; F. REY SARAVIA; S. SIMONETTI

Karlsruhe

Conferencia; 2nd International Conference on Materials for Energy, EnMat II; 2013

Spanish Initiative for Electronic Simulations with Thousands of Atoms (SIESTA) calculations has been performed to study the adsorption of one and two H atoms in a vacancy region of a Fe50Ni50 alloy. The vacancy favours H location. H debilitates the metal-metal bonds by forming interactions with the metallic matrix. The metal-metal bond strength decreases bigger percent with the introduction of the first H atom and no additional decohesion is observed in the metallic bonds when two H atom are present, but in this case more bonds are affected. The H impurities develop a negative charge while the closest Fe and Ni atoms result more positively charged. The H-metal excharge contributes to the decohesion process. The H-H interaction is very small. Each H atom bonds to the surrounding Fe and Ni instead of bonding with each other. The Fe-H interaction is stronger than any possible H-H interaction.