The paper reports the diffusion coefficients of grain boundary diffusion and grain boundary assisted lattice diffusion of Pd in Mg in Pd/Mg/Si system, a useful material for hydrogen storage, at 473 K in vacuum. The grain boundary diffusivity is measured by Whipple model and grain boundary assisted lattice diffusivity by plateau rise method using Pd depth profiles constructed by Rutherford backscattering spectrometry. It is established that grain boundary diffusivities are about six orders of magnitude faster than lattice diffusivities. Fine grained microstructure of Pd film, high abundance of defects in Mg film and higher stability associated with Pd-Mg intermetallics are responsible for the diffusion of Pd into grain boundaries and subsequently in the interiors of Mg. Besides the indiffusion of Pd, annealing also brings about an outdiffusion of Mg into Pd film. Examination by nuclear reaction analysis involving 24.Mg(p,p'gamma)24.Mg resonance reaction shows the occurrence of Mg outdiffusion. Minimization of surface energy is presumably the driving force of the process. In addition to Pd/Mg interface, diffusion occurs across Mg/Si (substrate) interface as well on increasing the annealing temperature above 473 K. These studies show that dehydrogenation of films accomplished by vacuum annealing should be limited to temperatures less than 473 K to minimize the loss of surface Pd, the catalyst of the hydrogen absorption-desorption process and Mg, the hydrogen storing element, by way of interfacial reactions.


    Access

    Access via TIB

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Studies on interdiffusion in Pd/Mg/Si films: Towards improved cyclic stability in hydrogen storage


    Additional title:

    Untersuchung der Interdiffusion in Pd/Mg/Si Filmen: Auf dem Weg zu einer verbesserten zyklischen Stabilität bei der Wasserstoffspeicherung


    Contributors:
    Sunitha, Y. (author) / Reddy, G.L.N. (author) / Kumar, Sanjiv (author) / Raju, V.S. (author)


    Publication date :

    2009


    Size :

    7 Seiten, 8 Bilder, 2 Tabellen, 28 Quellen




    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English





    Measuring Interdiffusion in Binary Liquids

    Gelles, S. H. / Markworth, A. J. | NTRS | 1982



    Interdiffusion of Rhenium and Poco Graphite

    Li, J. / Zee, R. H. / University of New Mexico; School of Engineering; Institute for Space and Nuclear Power Studies | British Library Conference Proceedings | 1998