LAUSR

Hydrogen absorption and desorption through diffusive processes and the accompanying phase transformations in hydrogen storage materials have been investigated by x-ray diffraction, thermogravimetry, pressure-composition-temperature isotherms, and electrical resistance measurements. We use time- and temperature-dependent magnetic measurements to gain a detailed understanding of these phenomena in palladium hydride PdH 0.64 prepared by severe plastic deformation via the high-pressure torsion method. The concept of our method is pursuing an increase in the ratio of the paramagnetic α-phase Pd+H to the diamagnetic β-phase PdH. An antiferromagnetic correlation appears between the paramagnetic moments of Pd at a low temperature and a huge discrete change in magnetization appears due to collective H desorption above room temperature. It is also verified that H diffusion and its desorption can be changed with the accumulation of the severe lattice strain.