Stability of Thermally Processed LaNi5-Based Alloys for Hydrogen Storage

Adriana Wrona; Agnieszka Sierczyńska; Katarzyna Bilewska; Małgorzata Kamińska; Mariusz Staszewski

doi:10.4028/www.scientific.net/SSP.203-204.423

Paper Titles

Calculation of Electronic Structure of the K-Phase Cells which are Involved in Thermobarically Induced Epitaxial Growth of Diamond Crystals in High-Carbon Fe-Al-Alloys
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Influence of the Crystallographic Orientation of CuZn30 Single Crystal on the Portevin-Le Chatelier Effect
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Study of Defects Structure in Fe-Al Alloys
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Influence of Overheating Temperature on the Shape of Primary Silicon Crystals in Hypereutectic Al-Si Cast Alloys
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Stability of Thermally Processed LaNi₅-Based Alloys for Hydrogen Storage
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On Frequencies of Occurrence of Geometrically Characteristic Grain Boundaries
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The Specific Heat Capacity and Oxidation Kinetics of NiAl, FeAl and TiAl Alloys
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Microstructural Characterization of Ni(Co)CrAlY Powders Designed for Thermal Spraying of Bondcoat for TBC Systems
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Crystalline and Lamellar Structure of Polypropylene Fibrillated Fibres
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Stability of Thermally Processed LaNi₅-Based Alloys for Hydrogen Storage

Abstract:

Hydrogen-absorbing compounds of AB₅-type are widely studied in view of their application not only as anode material in fuel cells but also in high-energy Ni-MH cells. Within this work nanocrystalline MmNi_3.55Al_0.3Mn_0.4Co_0.75 compounds, where Mm is La–rich mixture of rare earth elements, synthesized by High-Energy Ball Milling (HEBM) of arc-melted alloy and AB₅-type alloy/carbon composites prepared by CVD method were studied. As the compounds subjected to high temperature during preparation their thermal stability has been established after annealing at various temperatures. X-ray phase analysis has unambiguously proven that over 400°C single-phase MmNi_3.55Al_0.3Mn_0.4Co_0.75 starts to decompose into a multi-phase mixture with Ni-based solid solution as a main phase. Similar behaviour has been observed for composite material. Moreover, carbon distribution on surface of alloy particles is inhomogeneous as seen in microanalysis. Nevertheless, a substantial increase of hydrogen capacity has been observed for composite material in comparison with pure intermetallic compound, when used as anode material in direct borohydride fuel cell (DBFC).