Short-range structure of hydrogenated amorphous PdZr alloys by pulsed neutron total scattering

Abstract

The short-range structure of deuterided amorphous PdZr alloys was observed using pulsed neutron total scattering with a spallation neutron source installed at a 500 MeV proton booster synchrotron. The results show that deuterium atoms characteristically modify the local arrangements of metal atoms surrounding a deuterium atom in amorphous PdZrD alloys and are distributed in several different types of polyhedral hole. In amorphous Pd 0.35Zr 0.65D x , for example, a deuterium atom occupies a tetrahedral site at x < 0.2 and an octahedral site near x = 0.4. A further increase in the deuterium content leads to a local arrangement of five metal atoms surrounding a deuterium atom. Even in amorphous alloys metal atoms prefer to have hydrogen atom neighbours similar to the topological arrangement found in the corresponding crystalline metal hydrides.