TY - JOUR
T1 - Hydriding/dehydriding properties of nanocrystalline Mg87Ni 3Al3M7 (M = Ti, Mn, Ce, La) alloys prepared by ball milling
AU - Spassov, T.
AU - Rangelova, V.
AU - Solsona, P.
AU - Baró, M. D.
AU - Zander, D.
AU - Köster, U.
PY - 2005/8/2
Y1 - 2005/8/2
N2 - Nanocrystalline Mg87Ni3Al3M7 (M = Ti, Mn, Mm; Mm = Ce, La-rich mischmetal) hydrides were synthesized by reactive mechanical milling (RMM) in hydrogen atmosphere. Different degrees of the alloys hydrogenation were achieved varying the time of milling at a hydrogen pressure of 5 atm. The influence of the alloying elements (Ti, Mn, Mm) on the amount of the hydrides formed during RMM as well as on the temperature and enthalpy of hydrogen desorption was determined. The amount of hydride formed during RMM was found to be almost the same in the three alloys (∼35 wt.%); for the Ti containing alloy it was slightly higher. The Ti containing alloy reveals the lowest temperature of hydrogen desorption (∼210 °C) and the hydride in the alloy with Mn decomposes at the highest temperature (∼240 °C) among the three alloys studied. The enthalpy of H-desorption is highest for the sample alloyed with Mm (Ce, La), 70-72 kJ/mol; the Ti and Mn containing magnesium alloys have similar enthalpies of hydride decomposition, 56-60 kJ/mol. The alloys studied reveal higher equilibrium pressures of hydrogen absorption compared to nanocrystalline magnesium, indicating some thermodynamic destabilization of the hydride as a result of the alloying. Hydrogen absorption kinetics were studied at isothermal conditions at different temperatures and an influence of the alloying element was observed. The hydrogen absorption in the Ti containing alloy is substantially faster than in the alloys with Mn and Mm. © 2004 Elsevier B.V. All rights reserved.
AB - Nanocrystalline Mg87Ni3Al3M7 (M = Ti, Mn, Mm; Mm = Ce, La-rich mischmetal) hydrides were synthesized by reactive mechanical milling (RMM) in hydrogen atmosphere. Different degrees of the alloys hydrogenation were achieved varying the time of milling at a hydrogen pressure of 5 atm. The influence of the alloying elements (Ti, Mn, Mm) on the amount of the hydrides formed during RMM as well as on the temperature and enthalpy of hydrogen desorption was determined. The amount of hydride formed during RMM was found to be almost the same in the three alloys (∼35 wt.%); for the Ti containing alloy it was slightly higher. The Ti containing alloy reveals the lowest temperature of hydrogen desorption (∼210 °C) and the hydride in the alloy with Mn decomposes at the highest temperature (∼240 °C) among the three alloys studied. The enthalpy of H-desorption is highest for the sample alloyed with Mm (Ce, La), 70-72 kJ/mol; the Ti and Mn containing magnesium alloys have similar enthalpies of hydride decomposition, 56-60 kJ/mol. The alloys studied reveal higher equilibrium pressures of hydrogen absorption compared to nanocrystalline magnesium, indicating some thermodynamic destabilization of the hydride as a result of the alloying. Hydrogen absorption kinetics were studied at isothermal conditions at different temperatures and an influence of the alloying element was observed. The hydrogen absorption in the Ti containing alloy is substantially faster than in the alloys with Mn and Mm. © 2004 Elsevier B.V. All rights reserved.
KW - Hydriding/dehydriding
KW - Magnesium alloys
KW - Nanocrystalline
KW - Reactive mechanical milling
U2 - https://doi.org/10.1016/j.jallcom.2005.02.035
DO - https://doi.org/10.1016/j.jallcom.2005.02.035
M3 - Article
SN - 0925-8388
VL - 398
SP - 139
EP - 144
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
ER -