Location of deuterium atoms absorbed in nanocrystalline graphite prepared by mechanical alloying

Neutron diffraction is an important technique for studying the structure of hydride materials, H/D isotopic substitution was employed to observe the l ocation of deuterium atoms in deuterated nano-graphite because the coherent scattering length of deuterium is large enough to be observed in compariso n with that of the metal atoms forming hydrogen absorbing materials. The pr eparation of the nano-crystalline graphite and the absorption of deuterium atoms in the graphite were carried out simultaneously by mechanical alloyin g under D-2 gas atmosphere. The transformation from the hexagonal graphite as a starting material into amorphous-like carbon was observed by neutron d iffraction. The conformation in the graphite was changed by the creation of dangling bonds and deuterium was absorbed by the solid-gas reaction when t he milling proceeded. Two types of the deuterium coordinations were found i n radial distribution function, RDF(r). One is the C-D covalent bond and th e other is deuterium located between layers of the graphite. (C) 2001 Elsev ier Science BY All rights reserved.