Samples with MgmAlNin composition (m, n ≤ 3) were synthesized by ball milling in form of crystalline nanoparticles, and were found to be a single phase with partially disordered CsCl-type cubic structure. For compositions with large m and small n, minor quantities of Mg and Mg2Ni are segregated. XRD Rietveld refinements indicate that the two P m over(3, ̄) m sublattices basically have (Mg, Al) and (Mg, Al, Ni) occupations, respectively. Hydrogenation experiments on the Mg2AlNi2 sample by the PCI technique showed a reversible absorption/desorption of 1.4 wt% H2 with formation/decomposition of the MgH2 and Mg2NiH4 hydrides. The van't Hoff plot gives ΔrH = 67.7 kJ mol-1 (enthalpy of dehydrogenation), and T0 = 524 K (temperature of dehydrogenation at p = 0.1 MPa). A kinetic study of the gas release at 535 K showed a satisfactory behaviour, with a first fast step followed by a slower one in both the absorption and desorption processes. © 2008 Elsevier B.V. All rights reserved.
Parente, A., Nale, A., Catti, M., Kopnin, E., Caracino, P. (2009). Hydrogenation properties of Mg2AlNi2 and mechanical alloying in the Mg-Al-Ni system. JOURNAL OF ALLOYS AND COMPOUNDS, 477, 420-424 [10.1016/j.jallcom.2008.10.023].
Hydrogenation properties of Mg2AlNi2 and mechanical alloying in the Mg-Al-Ni system
CATTI, MICHELE;
2009
Abstract
Samples with MgmAlNin composition (m, n ≤ 3) were synthesized by ball milling in form of crystalline nanoparticles, and were found to be a single phase with partially disordered CsCl-type cubic structure. For compositions with large m and small n, minor quantities of Mg and Mg2Ni are segregated. XRD Rietveld refinements indicate that the two P m over(3, ̄) m sublattices basically have (Mg, Al) and (Mg, Al, Ni) occupations, respectively. Hydrogenation experiments on the Mg2AlNi2 sample by the PCI technique showed a reversible absorption/desorption of 1.4 wt% H2 with formation/decomposition of the MgH2 and Mg2NiH4 hydrides. The van't Hoff plot gives ΔrH = 67.7 kJ mol-1 (enthalpy of dehydrogenation), and T0 = 524 K (temperature of dehydrogenation at p = 0.1 MPa). A kinetic study of the gas release at 535 K showed a satisfactory behaviour, with a first fast step followed by a slower one in both the absorption and desorption processes. © 2008 Elsevier B.V. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.