Dresden 2003 – wissenschaftliches Programm
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M: Metallphysik
M 13: Wasserstoff in Metallen
M 13.1: Vortrag
Montag, 24. März 2003, 14:45–15:00, IFW D
Hydrogen Storage Properties of Nanocrystalline Mg-based Alloys Modified with Platinum Group Metals (PGMs) — •Nahla Ismail1,2, Monika Herrich1, Allin Pratt2, and Oliver Gutfleisch1 — 1IFW Dresden, Institute of Metallic Materials, P.O. Box 270016, D-01171 Dresden, Germany — 2Johnson Matthey Technology Centre, Sonning Common, Reading RG4 9NH, UK
High energy ball milling was employed to synthesise nanocrystalline (nc) Mg-based powders for hydrogen storage applications. Alloy additions and catalysts are known to improve the sorption kinetics. In this work, several platinum group metals (PGMs) have been utilised to modify the surface of nc- MgH2 or nc- Mg2NiH4 powders. The influence of PGMs concentrations and co-milling time are investigated. Gravimetric and thermal desorption studies combined with microstructural analysis using HRSEM and XRD illustrated the catalytic role of PGMs, yielding finally significantly reduced hydrogen desorption temperatures. Reactively milled Mg2Ni co-milled for 1 hour with Ru shows an onset temperature of hydrogen desorption as low as 80oC. In a second part, the high temperature hydride Mg2FeH6 is directly synthesised by mechanical alloying elemental powders in hydrogen atmosphere (reactive milling). Microstructural evolution starting with low Fe concentrations and the role of PGMs additions are investigated.