The location of atomic hydrogen in NiTi alloy: A first principles study

A first principles density functional theory study to investigate the H defect in NiTi alloy is presented. We have determined the interstitial H atom position in bulk B2 phase NiTi alloy. H positions on both the Ti and Ni terminated NiTi surfaces are calculated. Surface adsorptions of H atom on Ni/Ti terminated surfaces are calculated for a low surface coverage of 1.96 × 1014 cm−2. We have also calculated the penetration barrier energy for an H atom from the surface site to the bulk lattice site.