Interaction between Interstitial Hydrogen and Fe Atoms within the β-Hydride Phase in Nb_(1-y)Fe_yH_x Alloys

摘要

The influence of hydrogen on the electronic and structural properties of Nb_(1-y)Fe_y alloys has been studied with ~(57)Fe Moessbauer spectroscopy and X-ray diffraction. The results clearly indicate the β-NbH_x hydride formation in place of α-Nb phase. The quadrupole splitting and the isomer shift of β-hydride subspectrum have been considered in terms of interaction between the interstitials and the Moessbauer atoms within the hydride phase. We show that in disordered non-stoichiometric β-hydride formed in Nb_(1-y)Fe_yH_x alloy the Fe atoms can be really treated as probes that are sensitive to the change of the hydride sublattice configuration. The results indicate that the hydrogen-induced isomer shift relative to the unloaded alloys can be used as a measure of the mean number of hydrogen atoms next to the Fe probes. Both, the isomer shift and the quadrupole splitting indicate a configuration with three hydrogen atoms as nearest neighbours of Fe captured in β-hydride sublattice in Nb_((0.985/0.90))Fe((0.015/0.10)H_x alloys.