Effect of substitutional elements on hydrogen absorption properties in Mm-based AB5 alloys
TL;DR: In this paper, the authors studied the hydrogen absorption isotherms for the CaCu5 hexagonal structured alloys MmNi3.4, Mm Ni3.8Al 0.368Mn0.5Fe0.4Co 0.333V0.333Al0.3Fe0,4Fe 0.5Co 0,5Fe 0,6Al 0,7Al 0 0,8Al0 0.4Fe0 0,4Co0.
About: This article is published in Journal of Alloys and Compounds.The article was published on 2004-01-28. It has received 48 citations till now. The article focuses on the topics: Hydrogen & Hydrogen storage.
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TL;DR: In this paper, the authors explored the technical issues surrounding the use of hydrogen storage, in conjunction with a PEM electrolyser and PEM fuel cell, to guarantee electricity supply when the energy source is intermittent, most typically solar photovoltaic.
131 citations
TL;DR: In this paper, the role of Mn in C14 Laves phase alloys for battery applications was studied by adjusting the Mn content in exchange with Ni and Cr in three series of C14 AB2 Laves Phase alloys.
64 citations
TL;DR: In this paper, the effects of aluminum substitution to the structural, electrochemical, and gas phase hydrogen storage properties of C14-rich alloys were reported, including minor phases including C15 and TiNi, identified by X-ray diffraction analysis.
50 citations
TL;DR: In this article, the performance of metal hydride based cooling system (MHCS) is evaluated by characterizing intermetallic hydrides to determine their suitability in MHCS, and the effect of compositional changes on the variation of these parameters due to the variation in pressure concentration isotherm properties (storage capacity, plateau slope, hysteresis effect, etc.) was studied.
48 citations
TL;DR: In this article, a novel AB5-type, non-stoichiometric, lanthanum-rich MmNi3.03Si0.85Co0.60Mn0.31Al0.08 (Mm: Misch metal) hydrogen storage metal hydride alloy electrodes are prepared.
46 citations
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TL;DR: In this article, peak broadening in X-ray powder diffraction (XRD) profiles of LaNi5-based alloys after hydriding and dehydriding processes was investigated in order to clarify the mechanism of formation of lattice strain.
57 citations
TL;DR: In this article, the Zr 1− x Ti x MnFe-H 2 systems with x = 0.2 and 0.3 were studied as a function of composition, temperature, and hydrogen dissociation pressure (0.01-50 atm).
Abstract: The Zr 1− x Ti x MnFe-H 2 systems with x = 0.2 and 0.3 were studied as a function of composition, temperature (23–200 °C) and hydrogen dissociation pressure (0.01–50 atm). The hydrogen vapor pressure of the ZrMn 2 -H 2 system is raised approximately 400-fold by the replacement of zirconium by titanium and of manganese by iron without significantly impairing its hydrogen capacity. The hydrides of Zr 1− x Ti x MnFe alloys have dissociation pressures in the range 1–2 atm at room temperature (23 °C). The hydrogen densities of the alloys compared with that of liquid hydrogen range from about 1.0 to 1.4. The enthalpies and entropies of dehydrogenation are exceptionally low (10–11 kJ (mol H 2 ) −1 and 46–50 J (mol H 2 ) −1 K −1 respectively). The kinetics of hydrogen absorption and desorption are extremely fast. Desorption of hydrogen in the two-phase field α + β follows first-order kinetics with activation energies of 34–38 kJ mol −1 . The energetics of hydrogen charging and discharging for the Zr 0.8 Ti 0.2 MnFe alloy are smaller than those for LaNi 5 or other accepted hydrogen storage materials. Similarly, a hydride compressor using Zr 0.8 Ti 0.2 MnFe alloy appears to be significantly more efficient than the LaNi 5 hydride compressor.
52 citations
TL;DR: In this paper, the authors studied the hydrogen absorption-desorption characteristics of ternary alloys such as Mm1−x AxNi5 (A Ca, Ti; x = 0.05− 0.75), MmNi5−yBy (B ǫ, Co, Cr, Mn, V, V; x= 0.1−0.75).
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.
45 citations
TL;DR: In this article, the absorption of hydrogen by RTx alloys (R = Ce, La, Nd, Pr and MM (mischmetal)) has been studied at the Federal Bureau of Mines with the object of developing a suitable alloy absorbent for hydrogen storage at 25 °C and a pressure range of 1 − 10 atm.
Abstract: The absorption of hydrogen by RTx alloys (R = Ce, La, Nd, Pr and MM (mischmetal); T = transition metals, chiefly Co, Ni and Fe) has been studied at the Federal Bureau of Mines with the object of developing a suitable alloy absorbent for hydrogen storage at 25 °C and a pressure range of 1 – 10 atm. The ability to absorb and desorb hydrogen reversibly under these conditions (i.e. the working capacity) reached a maximum with the composition RT5. LaNi5 exhibited the highest capacity. Studies with MMCo5 showed that variations in individual rare earth contents in mischmetal had little effect upon the absorption properties of the alloys, but partial substitution of cobalt by other transition metals had a substantial effect. Interstitial oxygen and carbon in MMCo5 considerably reduced both the hydrogen absorption and the working capacity. The optimum composition for mischmetal-cobalt alloys with partial substitution of cobalt by other transition metals was found to be between MMCo4.25Ni0.75 and MMCo3.5Ni1.5. Up to 2.6 g atom H mol−1 of alloy could be reversibly stored between pressure limits of 1 atm and 10 atm at room temperature. Absorption of hydrogen by MMCo4.25Ni0.75 was largely unaffected by He, N2 and CH4 impurities in the gas, but was severely inhibited by O2, H2O, CO2 and CO impurities. Cyclic studies of morphology indicated that alloy decrepitation occurred more rapidly for MMCo3.5Ni1.5 than for MMCo4.25Ni0.75 during repeated absorption and desorption.
41 citations