Jump to main content
Jump to site search
Access to RSC content Close the message box

Continue to access RSC content when you are not at your institution. Follow our step-by-step guide.


Issue 46, 2012
Previous Article Next Article

Effect of the structure transformation on the (de-)hydrogenation hysteresis of La1−zYzHx films as studied by hydrogenography

Author affiliations

Abstract

The (de-)hydrogenation properties of La1−zYzHx (z = 0, 0.4, 1) thin films during the dihydride–trihydride transition were investigated by means of hydrogenography. We show that La-rich films, i.e. LaHx and La0.6Y0.4Hx, are almost hysteresis free in the temperature range 423–523 K. This appears to be due to a small and/or negative volume expansion and the absence of the structure transformation on hydrogenation. The presence of the small difference between absorption and desorption sloping plateaus in these films is assigned to minor plastic deformations due to the substrate clamping. In contrast, YHx films, which expand by about 12% in volume on hydrogenation and which exhibit an fcc–hex structure transformation, show a huge (2–3 orders of magnitude) hysteresis. This giant hysteresis is caused, according to our stress–strain analysis, by the clamping induced mechanical work done by the film during (de-)hydrogenation and the reorientation required to maintain the preferential orientation during the fcc–hex structure transformation. Using our stress–strain model, improved by an additional structural parameter (ΔGfcc–hex), we were able to reproduce the size of the hysteresis in both thin and thick YHx films measured at 523 K and at 295 K, respectively.

Graphical abstract: Effect of the structure transformation on the (de-)hydrogenation hysteresis of La1−zYzHx films as studied by hydrogenography

Back to tab navigation

Article information


Submitted
13 Jul 2012
Accepted
24 Aug 2012
First published
13 Sep 2012

J. Mater. Chem., 2012,22, 24453-24462
Article type
Paper

Effect of the structure transformation on the (de-)hydrogenation hysteresis of La1−zYzHx films as studied by hydrogenography

Y. Pivak, H. Schreuders and B. Dam, J. Mater. Chem., 2012, 22, 24453
DOI: 10.1039/C2JM34594C

Search articles by author

Spotlight

Advertisements