Hydrogenation of Zr–Cu–Al–Ni–Pd metallic glasses by electrochemical means

Amorphous materials of Zr–Cu–Ni–Al systems have shown attractive electrochemical hydrogen absorption properties. A comparison between Zr 60Cu 15Al 10Ni 10Pd 5 and Zr 65Cu 17.5Al 7.5Ni 10 reveals that the palladium (Pd) increases the hydrogen absorption capacity. Charging melt-spun Zr 60Cu 15Al 10Ni 10Pd 5 ribbons electrochemically to different hydrogen-to-metal (H/M) ratios and following the effusion of hydrogen by thermal desorption analysis (TDA) reveals hydrogen desorption from interstitial sites of high energy levels at temperatures below 630 K. Zirconium hydrides are formed above 630 K. At higher temperatures partial desorption of hydrogen occurs. The thermal stability observed with differential scanning calorimetry (DSC) of the amorphous phase has been significantly deteriorated by hydrogen absorption. After hydrogenation, the crystallization behaviour shows suppression of the characteristic quasicrystalline phase and depends on the hydrogen content. Therefore, at low hydrogen concentrations H/M = 0.3, Cu and/or Cu-rich phases are primarily formed while at high hydrogen concentrations H/M ≥ 0.9 Zr-hydride phase(s) are mainly formed.