Showing papers in "Journal of Alloys and Compounds in 1999"

TL;DR: The hydrogen storage properties of MgH 2 are significantly enhanced by a proper engineering of the microstructure and surface as discussed by the authors, which gives remarkable improvement of absorption/desorption kinetics.

TL;DR: In this article, an extensive mechanical milling was used to make MgH2-Tm (Tm=3d-transition elements Ti, V, Mn, Fe, Ni) nanocomposite powders.

TL;DR: A broad historical and property-related review of hydriding alloys can be found in this article, where the main focus is on reactions of alloys with gaseous H 2 and their important H-capacity and PCT (pressure composition temperature) properties.

TL;DR: In this article, the authors present a systematic study of structural modifications and hydrogen absorption-desorption kinetics of ball-milled magnesium hydride, and they show that after only 2 h of milling, a metastable orthorhombic (γ)-morphological phase is formed.

TL;DR: In this paper, the hydrogen storage properties of a new composite MgH2+V prepared by ball milling were presented. But the results were limited to hydrogen desorption at 473 K under vacuum and re-absorbation at room temperature.

TL;DR: In this article, a remarkable enhancement of hydrogen desorption kinetics has been found for magnesium-based materials, ball-milled in the hydrogenated state, enabling the mixture to operate at temperatures of 220°C-240°C, with excellent absorption/desorption Kinetics and with total hydrogen capacity exceeding 5 wt%.

TL;DR: In this paper, a satisfactory agreement between experimental and calculated enthalpy and entropy values for the formation of MgH2 is achieved; systematic deviations are found only at higher temperatures (∼480°C) and experimental determination of PCIs (absorption and desorption mode) has been carried out in the temperature range 403-520°C, using Mg powders of different origin and particle size.

TL;DR: In this article, the effect of titanium and zirconium catalysts on the dehydrogenation kinetics of NaAlH4 was investigated and it was shown that a combination of both titanium and Zr(OPr) catalysts can achieve a greater than 4 wt% cyclable hydrogen capacity.

TL;DR: In this paper, the high pressure phase γ-MgH2 was formed by heating the low-pressure phase MgH 2 in a multianvil press at 2 GPa pressure to 1070 K for 120 min and successive rapid quenching.

TL;DR: In this paper, a ternary magnesium-based alloy CaMg 2 Ni 9 has been synthesized, and its crystal structure was determined by Guinier-Hagg X-ray and neutron powder diffraction.

TL;DR: Amorphous and nanocrystalline Mg-based alloys were produced by rapid quenching (melt-spinning) and their hydrogenation properties were studied as discussed by the authors.

TL;DR: In this paper, two ternary magnesium-based alloys, YMg2Ni9 and (Y0.5Ca 0.5)(MgCa)Ni9 have been synthesized and their crystal structures were determined by Guinier-Hagg X-ray powder diffraction.

TL;DR: Titanium silicon carbide (Ti3SiC2) was synthesized by reactive sintering of elemental reactants as mentioned in this paper, and the ternary compound was found to be stable at temperatures as high as 1800°C under an argon atmosphere.

TL;DR: In this paper, complex alkali metal hydrides fabricated by mechano-chemical processes exhibit very good reactivity in hydriding/dehydriding reactions and have excellent cyclability and cover a wide range of operational temperatures and pressures.

TL;DR: The relation between the migration of the δ/γ interface boundary and the growth of austenite as a function of aging treatment in SAF 2205 duplex stainless steel was investigated in this paper.

TL;DR: In this article, an overview of the properties of metal hydride electrodes used for battery applications is presented. But the focus is on the AB5 electrodes but others are treated as well, emphasizing the effects of composition changes with respect to both the A and the B components.

TL;DR: In this paper, the crystal structures, the lattice parameters and the characteristics of hydrogen storage at 303 K have been investigated in ternary alloys of the Ti-Cr-V system.

TL;DR: In this paper, three aluminum-silicon alloys containing 7, 10 and 19 wt −% silicon were synthesized using a novel technique commonly known as disintegrated melt deposition technique, and the results following processing revealed that a yield of at least 80% can be achieved after defacing the shrinkage cavity from the as-processed ingots.

TL;DR: In this paper, the physico-chemical properties of zirconium hydride such as mechanical and thermal properties have been studied in the form of pellets (6 mm φ×10 mm l) with hydrogen contents with 1.5-1.7 H/Zr, which were fabricated directly from Zr metal in a modified UHV Sieverts apparatus.

TL;DR: In this article, a model for the tetragonal compound Ni2MnGa and the non-stoichiometric phases was developed with the help of transmission electron microscope (TEM) data, X-ray powder diffraction measurements, and a computational simulation.

TL;DR: In this article, a new in situ system with the functions of thin film formation and analysis of hydrogen absorption-desorption properties has been developed to clarify hydrogen storage properties in nano-scaled composites.

TL;DR: In this article, a ferromagnetic spin structure with magnetic moments oriented perpendicular to the c-axis of the hexagonal nuclear structure is observed with magnetic saturation moment 2.2 μB at 4.2 K from neutron diffraction and 2.0 μB from magnetic measurements and decreases in a Brillouinlike manner on heating to TC=575 K.

TL;DR: In this article, the direct synthesis of Na3AlH6 and Na2LiH6 by energetic mechanical alloying of stoichiometric mixtures of NaH, LiH and NaAlH4 was investigated.

TL;DR: A thorough Mossbauer effect investigation of all the phases in the Li-Sn binary phase diagram has been made in this article, where the compounds studied were verified to have the same crystal structures as those reported in the literature and the center shifts (relative to CaSnO 3 ), quadrupole splittings, number of Sn sites and their abundance were determined for each of the phases by fitting model spectra to the observed data.

TL;DR: The mixed-level state of ∂-Pu as discussed by the authors is consistent with most of the anomalous properties of Pu, including the near-degeneracy of α-and δ-phases of Pu and the unusual equilibrium volume, elastic constants, and thermal expansion of δ phase.

TL;DR: In this paper, the structural location and effect due to partially substitution of Na + and CO 3 2− to Ca ++ and PO 4 3−, respectively, in hydroxyapatite, Ca 10 (PO 4 ) 6 OH 2 (HAP), synthesised in aqueous solution have been investigated by X-ray powder pattern fitting methods.

TL;DR: The production of small-sized Ni-MH batteries, which amounts to some 40% of market share for portable appliances, is still growing because of an increase in the energy density per volume and also a reduction in price.

TL;DR: In this paper, preliminary XPS and XRD studies of the 3C-SiC polycrystals (with the grain size of order of 100 μm) grown by the sublimation method were performed.

TL;DR: In this article, the authors used thermal desorption spectroscopy (TDS) to reveal the nature of defects acting as trapping sites of hydrogen, which themselves annihilate in the course of TDS measurement.

TL;DR: In this article, the atom insertion into the body-centered vacant site was attempted under high pressure and temperature conditions, and it was found that various 14-group elements were selected for atom insertion under pressure of 30 MPa to 5 GPa, resulting in the formation of new filled-skutterudite phase MxCo4Sb12.