Magnetic measurements of hydrogen desorption from palladium hydride PdH0.64 prepared by severe plastic deformation

Abstract

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 PdH0.64 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.

Study on micropillar arrangement optimization of wireless-electrodeless quartz crystal microbalance sensor and application to a gas sensor

“…This volume was equivalent to 235 times the volume of the Pd thin film of 4.25 × 10 -5 mm 3 . The volume of hydrogen that can be stored is about 1000 times the volume of Pd, [43][44][45] and therefore the stored amount obtained by the frequency shift was an appropriate value. Because Pd expands in volume with hydrogen storage, the quartz oscillator is warped due to this expansion, and as a result, the frequency shift can be occurred.…”

“…Considering that the quartz oscillator was adsorbed on the surface of the PDMS micropillars in the atmosphere, this piezoelectric analysis using the FEM simulation was conducted assuming that the quartz oscillator and the PDMS micropillars were joined. In addition, because the Q-factor of the wirelesselectrodeless PDMS QCM sensor for which the placement of the micropillars was optimized was very high, the palladium (Pd), which is known as a hydrogen storage material, [43][44][45] was formed on the surface of the quartz oscillator as a sensitive film and the characteristic as a hydrogen-gas sensor was investigated. As a result, detecting a very low concentration of hydrogen gas was successful.…”

Improvement of hydrogen detection sensitivity of palladium film by in-plane compressive plastic deformation and application to hydrogen gas sensor

“…The palladium has the ability to absorb hydrogen gas about 1000 times its own volume. [30][31][32] In a previous study, Jung and Sakai investigated the shape change caused by the absorption and desorption of hydrogen using a rolled palladium plate with a thickness of 1 mm. As a result, it was proved that the thickness of the plastically deformed palladium plate increased by about 2.6-2.8 times when hydrogen gas was absorbed.…”

“…On the other hand, the hydrogen absorption mass was 13.0-16.2 ng in the case of the ICPD sputtering method, which corresponded to 1253-1566 times larger than the volume of palladium film. It is known that the palladium can absorb the hydrogen gas, which is about 1000 times of its own volume, [30][31][32] ) and therefore the hydrogen absorption amount of the palladium film deposited by the conventional sputtering method was appropriate. On the other hand, because the hydrogen absorption amount of palladium film deposited by the ICPD sputtering method was 1500 times or more, this means that the hydrogen gas was absorbed more than the original absorption characteristics of palladium.…”

Severe Plastic Deformation through High-Pressure Torsion for Preparation of Hydrogen Storage Materials -A Review

“…In HPT-processed samples, hydrogen-induced softening and plasticity were observed and the hydride phase was more stable than that of only annealed samples. Mito et al 116) developed a magnetic measurement system to investigate the hydrogen desorption performance of HPTprocessed PdH 0.64 . TiV alloy was synthesized using HPT by Edalati et al 117) for hydrogen storage.…”