TY - JOUR
T1 - Microstructural characterization and hydrogenation study of extruded MgFe alloy
AU - Lima, G. F.
AU - Peres, M. M.
AU - Garroni, S.
AU - Baró, M. D.
AU - Kiminami, C. S.
AU - Ishikawa, T. T.
AU - Botta, W. J.
AU - Jorge, A. M.
AU - Suriñach Cornet, Santiago
PY - 2010/8/1
Y1 - 2010/8/1
N2 - Mg-based nanocrystalline alloys or nanocomposites are promising materials for hydrogen storage in the solid state, which is a more effective and safer storage medium than pressurized or liquefied hydrogen. Among the many Mg-based hydrides of interest for hydrogen storage, Mg2FeH6 is in a special position due to its relatively high gravimetric capacity of 5.5% and excellent volumetric density of 150 kg H2/m3. This work involved a study of the synthesis and processing of Mg-based alloys of this type, produced by high-energy ball milling and hot extrusion. A mixture of 2Mg-Fe was prepared by high-energy ball milling under argon gas. The resulting powder was cold-pressed to produce cylindrical pre-forms, which were then extruded and the sorption properties were analyzed in a microbalance and in a Sieverts apparatus. Phase formation, microstructural evolution, desorption temperatures, and hydrogen storage capacity were analyzed by X-ray diffraction, scanning electron microscopy (SEM), differential scanning calorimetry, and thermogravimetric techniques. The results showed that Mg2FeH 6 was formed and the hydrogen reaction was reversible. SEM observations indicate a microstructure composed of nanosized grains in the range of 30-80 nm inside particles of about 50 μm, and Mg2FeH 6 formed mainly at the particle interfaces. The desorption temperature started at about 225 °C, reaching a maximum at 440 °C with low capacity of absorption, indicating low absorption/desorption kinetics, probably due to bulk diffusion limitations. © 2010 Elsevier B.V.
AB - Mg-based nanocrystalline alloys or nanocomposites are promising materials for hydrogen storage in the solid state, which is a more effective and safer storage medium than pressurized or liquefied hydrogen. Among the many Mg-based hydrides of interest for hydrogen storage, Mg2FeH6 is in a special position due to its relatively high gravimetric capacity of 5.5% and excellent volumetric density of 150 kg H2/m3. This work involved a study of the synthesis and processing of Mg-based alloys of this type, produced by high-energy ball milling and hot extrusion. A mixture of 2Mg-Fe was prepared by high-energy ball milling under argon gas. The resulting powder was cold-pressed to produce cylindrical pre-forms, which were then extruded and the sorption properties were analyzed in a microbalance and in a Sieverts apparatus. Phase formation, microstructural evolution, desorption temperatures, and hydrogen storage capacity were analyzed by X-ray diffraction, scanning electron microscopy (SEM), differential scanning calorimetry, and thermogravimetric techniques. The results showed that Mg2FeH 6 was formed and the hydrogen reaction was reversible. SEM observations indicate a microstructure composed of nanosized grains in the range of 30-80 nm inside particles of about 50 μm, and Mg2FeH 6 formed mainly at the particle interfaces. The desorption temperature started at about 225 °C, reaching a maximum at 440 °C with low capacity of absorption, indicating low absorption/desorption kinetics, probably due to bulk diffusion limitations. © 2010 Elsevier B.V.
KW - Complex hydrides
KW - Hot extrusion
KW - Hydrogenation process
KW - Mg alloy
U2 - 10.1016/j.jallcom.2010.03.101
DO - 10.1016/j.jallcom.2010.03.101
M3 - Article
SN - 0925-8388
VL - 504
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
ER -