| Titre : | Role of additives in LiBH4–MgH2 reactive hydride composites for sorption kinetics (2011) |
| Auteurs : | U. Bösenberg, Auteur ; J.W. Kim, Auteur ; D. Gosslar, Auteur |
| Type de document : | Article : texte imprimé |
| Dans : | Acta materialia (Vol. 58 N° 9, Mai 2010) |
| Article en page(s) : | pp. 3381–3389 |
| Note générale : | Métallurgie |
| Langues : | Anglais |
| Tags : | Hydrogen storage Nanocomposites Heterogeneous nucleation of phase transformations Phase transformation kinetics |
| Résumé : | 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. |
| DEWEY : | 669 |
| ISSN : | 1359-6454 |
| En ligne : | http://www.sciencedirect.com/science/article/pii/S1359645410000984 |
