Yasuaki Osumi

Bio: Yasuaki Osumi is an academic researcher from Industrial Research Institute. The author has contributed to research in topics: Hydrogen & Hydride. The author has an hindex of 10, co-authored 29 publications receiving 407 citations.

Hydrogen absorption-desorption characteristics of MmNiAlM and MmNiMnM alloys (Mm misch metal)

Abstract: In order to reduce the large hysteresis effect in MmNi hydrides (Mm  misch metal) we studied the hydrogen absorption-desorption characteristics of multicomponent alloys such as MmNi5−xAl(Mn)y−zMz and MmNi5−xAl(Mn)yM2 (M = Co, Cr, Cu, Nb, Ti, V, Zr; x = 0.3 − 0.5; y = 0.3 − 0.5; z = 0.05 − 0.1). The substitution or addition of the element M eliminates the large hysteresis effect that occurs during an absorption-desorption cycle. The hysteresis factor (equal to In( P a P d )) for MmNi4.7Al0.3M0.1 hydrides decreased for additives M in the following order: Zr > Co > Cr > Ti,V > Cu. Investigations of the effects of cycling showed that spalling occurred more rapidly for MmNi4.5Mn0.5 than for MmNi4.5Mn0.5Zr0.005 and MmNi4.5Mn0.5Zr0.1.

Hydrogen absorption-desorption characteristics of mischmetal-nickel-aluminum alloys

Abstract: The hydrogen absorption and desorption characteristics of mischmetal (Mm)-nickel-aluminum alloys were investigated. MmNi5−xAlx (x = 0.25 −0.5) have been found to have the same hexagonal structure as LaNi5 and MmNi5, and they reacted readily with hydrogen to form the hydrides MmNi4.75 Al0.25H5.4, MmNi4.65Al0.35H 5.3H5.3 and MmNi4.5Al0.5H4.9 (hydrogen content: 1.3,1.2 and 1.2 wt.%, respectively) under 60 atm hydrogen pressure at room temperature. The dissociation pressures of these hydrides were dependent on the aluminum content (aluminum partially substitutes for nickel) and the value of log Pbecame lower than the value for MmNi5 hydride as x increased. The enthalpy change on hydride formation as determined from the dissociation isotherms for the MmNi4.5Al0.5-H system was − 5.5 kcal (mol H2)−1; this value was smaller than those for LaNi5 and MmNi5. The dissociation pressure at 30 °C was 3 atm and was nearly the same as that of LaNi5. The desorption rate of hydrogen for MmNi4.5Al0.5 was larger than those for LaNi5 and MmNi5) and a value of 2.1 – 4.3 kcal mol−1 was obtained for the apparent activation energy of hydrogen desorption. For MmNi4.5Al0.5 the hydrogen absorption-desorption cycle was repeated 30 times, but no variation in the hydrogen absorption-desorption capacity was observed. The hydride of MmNi4.5A10.5 proved to be suitable for use as a stationary hydrogen storage material.

Development of mischmetal-nickel and titanium-cobalt hydrides for hydrogen storage

Abstract: Fundamental studies were carried out to develop hydrides of mischmetal-nickel (Mm-Ni) and Ti-Co alloys with suitable properties for use as stationary hydrogen storage materials. In order to improve the properties of MmNi5 and TiCo hydrides we studied the hydrogen absorption-desorption characteristics of ternary alloys such as Mm1−x AxNi5 (A  Ca, Ti; x = 0.1−0.75), MmNi5−yBy (B  Al, Co, Cr, Mn; y = 0.1 − 4), Ti1−xAxCo and TiCO1−x Ax (A  Cr, Cu, Fe, La, Mn, Ni, V; x = 0.05− 0.5). The hydrides of MmNi4.5Al0.5, MmNi2.5Co2.5, MmNi4.5Cr0.5, MmNi4.5Mn0.5, TiCo0.5Mn0.5 and TiCo0.5Fe0.5, judged according to an appropriate set of criteria, rank higher than or equal to those of LaNi5, MmNi5, TiFe and TiCo and have properties suitable for a stationary hydrogen storage material.

Hydrogen storage properties of Ti1 + xCr2−yMny alloys☆

Abstract: Fundamental studies were performed with the aim of developing hydrides of titanium-based alloys with suitable properties for hydrogen and energy storage applications. We investigated the hydrogen absorption-desorption characteristics of the alloy Ti1 + xCr2−yMny (0.1 ⩽ x ⩽ 0.3; 0 ⩽ y ⩽ 1). The rate of the initial activation process increased as x was increased, but the reversible hydrogen storage capacity decreased. Ti1 + xCr2−yMny reacted readily with hydrogen to form hydrides at a hydrogen pressure of 40 atm and −20 °C. The reversible hydrogen storage capacity of Ti1.2Cr2−yMny decreased with decreasing manganese content while the plateau pressure increased. The hysteresis in the absorption-desorption isotherms decreased markedly for titanium concentrations in the range 0.2 ⩽ x ⩽ 0.3 and for manganese concentrations in the range 0.5 ⩽ y ⩽ 0.8.

Hydrogen absorption-desorption characteristics of misch metal-nickel-silicon alloys

Abstract: The hydrogen absorption and desorption characteristics of misch metal-nickel-silicon alloys were investigated. The alloys MmNis5−ySiy (Mm denotes misch metal and 0.4 ⩽ y ⩽ 0.8) were found to have the same hexagonal structure as LaNi5 and MmNi5, and they reacted readily with hydrogen to form the hydrides MmNi4.6 Si0.45H4.35, MmNi4.5 Si0.5H3.8, MmNi4.4Si0.6H2.1 and MmNi4.2Si0.8H3.1 (hydrogen contents of 1.0 wt.%, 0.9 wt.%, 0.5 wt.% and 0.7 wt.% respectively) under a hydrogen pressure of 60 atm at room temperature. The dissociation pressures of these hydrides were dependent on the silicon content (the silicon partially substitutes for nickel), and the value of log P became lower than that for MmNi5 hydride as y was increased. The enthalpy changes on hydride formation as determined from the dissociation isotherms for the MmNi4.5Si0.5-H and MmNi4.2Si0.8-H systems were −6.6 kcal (mol H2)−1 and −9.0 kcal (mol H2)−1 respectively; the value for the former was smaller than that for LaNi5, and the value for the latter was greater than those for LaNi5 and MmNi5. The dissociation pressures of these hydrides at 20 °C were 7.5 atm and 1.5 atm respectively. The desorption rate of hydrogen for MmNi4.2Si0.8 was larger than those for LaNi5 and MmNi5, and a value of 10.9–12.0 kcal mol−1 was obtained for the apparent activation energy of hydrogen desorption. The hydrides of MmNi4.6Si0.4, MmNi4.5Si0.5 and MmNi4.5Si0.8 have properties which make them suitable as stationary hydrogen storage materials.

Hydrides formed from intermetallic compounds of two transition metals: a special class of ternary alloys

Abstract: The authors review available experimental information on the existence, thermodynamic stability and physical properties of hydrides formed by the absorption of hydrogen gas in intermetallic compounds of two transition metals. The emphasis is on stability. It is shown that empirical models for the stability of ternary hydrides can be reconciled with ideas based on the results of band structure calculations of (binary) metallic hydrides. It is concluded that metallic hydrides can be looked upon as alloys of metallic hydrogen. In addition to the thermodynamic properties of ternary metallic hydrides the authors discuss experimental information on electronic properties (magnetic, super-conductivity, band structure features) and on crystallographic and metallurgical properties (neutron scattering, nuclear and electron spin resonance, Mossbauer spectroscopy, diffusion). Applications are briefly reviewed.

Storing energy in metal hydrides: a review of the physical metallurgy

Abstract: Metal hydrides, as energy storage media, are receiving considerable attention. The amount of literature concerning the properties of these materials has increased markedly over the past few years. In this paper, we conduct a review of the alloy groups which absorb large quantities of hydrogen. These alloy classes are designated as AB5, AB, AB2, AB3 and A2B7 and Mg-based compounds. These materials are discussed with emphasis placed on thermodynamic and kinetic properties, activation and deactivation, poisoning effects and storage capacity.