%0 journal article
%@ 1359-6454
%A Boesenberg, U., Kim, J.W., Gosslar, D., Eigen, N., Jensen, T.R., Bellosta von Colbe, J.M., Zhou, Y., Dahms, M., Kim, D.H., Guenther, R., Cho, Y.W., Oh, K.H., Klassen, T., Bormann, R., Dornheim, M.

%D 2010
%J Acta Materialia
%N 9
%P 3381-3389 
%R doi:10.1016/j.actamat.2010.02.012
%T Role of Additives in LiBH4-MgH2 Reactive Hydride Composite sorption reactions
%U https://doi.org/10.1016/j.actamat.2010.02.012
9 
%X 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.