Hydrogen storage in binary and ternary Mg-based alloys : A comprehensive experimental study Kalisvaart Mg-Al-Fe, the properties are clearly worse compared to the other ternary combinations.These differences are explained by considering the properties of all the different phases present during cycling in terms of their hydrogen affinity and catalytic activity. Based on these considerations, some general design principles for Mg-based hydrogen storage alloys are suggested.

We studied the hydrogen absorption and desorption properties of thin Pd-covered Mg1−xAlx alloy films as a function of temperature and alloy composition. Using neutron reflectometry, we were able to determine the hydrogen content and the hydrogen distribution within these MgAl films in situ. For all films, hydrogen was uniformly dispersed within the MgAl film and no hydrogen was observable in the Pd cover layer. The Mg0.7Al0.3 film shows an appreciable 4.1wt% stored hydrogen and improved desorption characteristics with complete desorption at a temperature of 448K.

This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. We used neutron reflectometry (NR) to study the structural changes of thin Pd-capped Mg 0.7 Al 0.3 and Mg 0.6 Al 0.4 alloy films after hydrogen absorption and during hydrogen desorption. NR enabled us to determine the hydrogen content and hydrogen distribution in these thin MgAl alloy films along with the structural changes associated with the desorption process. The thin films expand by about 20% during the hydrogen absorption and the hydrogen is stored only in the MgAl layer with no hydrogen content in the Pd layer. The Mg 0.7 Al 0.3 films are fully desorbed at 448 K, whereas for the Mg 0.6 Al 0.4 films a temperature of 473 K is needed to fully desorb the hydrogen. Our NR measurements show that the higher annealing temperature needed to desorb the hydrogen from the Mg 0.6 Al 0.4 films led to an interdiffusion of the Pd layer into the MgAl layer. This Pd interdiffusion was also observed in a Mg 0.7 Al 0.3 film after a 9 h annealing at 473 K. So, the Pd interdiffusion into a MgAl film that has been charged with hydrogen is a common feature of the Pd/Mg 0.7 Al 0.3 and Pd/Mg 0.6 Al 0.4 alloy system. In contrast, for the as-prepared hydrogen-free Pd/Mg 0.7 Al 0.3 film the Pd layer stays intact and only a small interdiffusion zone occurs at the Pd/MgAl interface. Crown

Access and use of this website and the material on it are subject to the Terms and Conditions set forth at A systematic neutron reflectometry study on hydrogen absorption in thin Mg1-xAlx alloy films Fritzsche, H.; Poirier, E.; Haagsma, J.; Ophus, C.; Luber, E.; Harrower, C. T.; Mitlin, D.http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=fr L'accès à ce site Web et l'utilisation de son contenu sont assujettis aux conditions présentées dans le site LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D'UTILISER CE SITE WEB. NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?action=rtdoc&an=16959085&lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?action=rtdoc&an=16959085&lang=fr READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE.http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. Questions?Contact the NRC Publications Archive team at PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information. NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://doi.org/10.1139/P09-085Canadian Journal of Physics, 88, p. 723-728, 2010-09-01 Photometry, radiometry and "the candela": evolution are being considered now in terms of fundamental constants to provide a more universally realizable quantum-based SI system. This paper also introduces for the first time a fundamental constant for photometry.

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