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Role of additives in LiBH4–MgH2 reactive hydride composites for sorption kinetics
- Source :
-
Acta Materialia . May2010, Vol. 58 Issue 9, p3381-3389. 9p. - Publication Year :
- 2010
-
Abstract
- Abstract: The influence of additives on the reaction kinetics and microstructure refinement in LiBH4–MgH2 composites is investigated in detail. Indications of the rate-limiting processes during the reactions are obtained by comparison of the measured reaction kinetics with simulations with one specific rate-limiting process. The kinetics of the sorption reactions are derived from volumetric measurements as well as from in situ X-ray diffraction measurements. During desorption, the hydrogen is released at a constant rate, which is possibly correlated with the one-dimensional growth of MgB2 platelets. In contrast, the kinetic curves of the absorption reactions exhibit the typical shape of contracting-volume controlled kinetics. The microscopical interpretation of kinetic measurements are supported by transmission electron microscopy images confirming the formation of additive-nanostructures in the grain boundaries upon cycling. The present investigations underline the importance of the additives as nucleation substrates and the influence of microstructure on the reaction kinetics. [Copyright &y& Elsevier]
Details
- Language :
- English
- ISSN :
- 13596454
- Volume :
- 58
- Issue :
- 9
- Database :
- Academic Search Index
- Journal :
- Acta Materialia
- Publication Type :
- Academic Journal
- Accession number :
- 49790464
- Full Text :
- https://doi.org/10.1016/j.actamat.2010.02.012