Insight into the Hydrogenation Properties of Mechanically Alloyed Mg₅₀Co₅₀ from the Local Structure

The local structure of mechanically alloyed Mg 50 Co 50 and its deuteride, Mg 50 Co 50 D 75, was investigated using the atomic pair distribution function (PDF) analysis of neutron and synchrotron X-ray total scattering data. The purpose of our study was to obtain the structural information of these amorphous alloys and understand their hydrogen storage properties. We found that the body centered cubic (bcc) structural model with the uniform distribution of Mg and Co atoms proposed by earlier studies was not able to explain neutron and X-ray PDFs at the same time. Our data suggest that the local environment of Mg is different from that of Co. A two-phase model composed of MgCo 2 and Mg 2 CoD 5 (Mg 2 Co for the alloy sample) qualitatively reproduced the main features of experimental PDFs and explained the amount of hydrogen absorbed by Mg x Co 100- x .