Hydrogen in amorphous Zr76Fe24

Abstract

The hydrogenation of amorphous Zr₇₆Fe₂₄ ribbons has been studied by Mossbauer spectroscopy, X-ray photoelectron spectroscopy and differential scanning calorimetry. The effusion of hydrogen has been followed by gas chromatography. The amorphous alloys were charged electrolytically to a concentration of 2.9 wt.% hydrogen, corresponding to the nominal composition Zr₇₆Fe₂₄H₂₄₆. Analysis of the Mossbauer and photoelectron spectra indicates that the hydrogen atoms preferentially occupy sites which are very similar to those in crystalline ZrH₂. Hydrogenation is found to decrease the crystallisation temperature by approximately 150K compared with uncharged samples and the crystallisation products are also found to be different. Macroscopic diffusion of hydrogen in amorphous Zr₇₆Fe₂₄ is very slow with negligible changes in the Mossbauer spectra of charged sampled discerned five weeks after charging.