Abstract
NMR measurements of proton rotating-frame relaxation times were used to deduce hydrogen diffusion parameters for the FCC and FCT phases of ZrHx over the stoichiometry range 1.60a is independent of hydrogen content for xa decreases as x increases for 1.80a very rapidly as x approaches 2.0. This latter behaviour is associated with the energy required to create the hydrogen sublattice vacancies responsible for the proton motion.