Wyse, Richard
(2014).
Investigation of Zr-based amorphous alloy membranes for hydrogen purification.
University of Birmingham.
M.Res.
Abstract
This project focused on the fabrication and characterization of zirconium‐copper and zirconium‐copper‐titanium amorphous alloys as hydrogen purification membranes.
Binary ribbons of Zr55Cu45 and Zr58Cu42 (wt%) (Zr46Cu54 and Zr49Cu51 at% respectively) were fabricated by melt spinning. DSC analysis determined the thermal behaviour of each ribbon under argon and hydrogen gases at 3 bar. Both ribbons exhibited similar DSC profiles including a typical crystallization peak under hydrogen at 263.9 °C and 302.9 °C respectively, but also exhibited an additional exothermic reaction around 162.7 °C and 123.3 °C respectively, also under hydrogen. XRD analysis as well as hydrogen solubility measurements showed the lower temperature peak was not crystallization or hydrogenation but an alteration of the crystal structure and stress relaxation event. The ability for both membranes to increase hydrogen uptake with increasing temperature at various pressures was demonstrated. The higher hydrogen solubility of the second binary (Zr58Cu42 wt% / Zr49Cu51) sample, in comparison to the first binary sample, was attributed to either a lower copper content and/or a lower degree of crystallinity.
A ternary ribbon Zr33Cu59Ti8 wt% (Zr25Cu64Ti11 at%) was also fabricated by melt spinning to investigate the addition of Ti to a Zr‐Cu based alloy. DSC measurements showed a similar thermal profile to the binary alloys, including the stress relaxation event at lower temperature (152.4 C). The ternary sample exhibited a lower crystallization temperature in comparison to both the binary alloys under hydrogen. In‐situ XRD analysis suggested that although Ti addition may promote the formation of an amorphous phase, it has a tendency to reduce the thermal stability of the alloys.
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