(576e) Amorphous Membranes for Hydrogen Separation Based On Ni-Nb-Zr Alloys

Authors: 
Pal, N. K. - Presenter, University of Nevada, Reno
Kim, S. - Presenter, University of Nevada, Reno
Chien, W. - Presenter, University of Nevada, Reno
Lamb, J. - Presenter, Sandia National Laboratories
Talekar, A. - Presenter, University of Nevada, Reno
Chandra, D. - Presenter, University of Nevada, Reno


Inexpensive metallic glass membranes based on Ni-Nb-Zr may replace Pd alloy membranes for hydrogen separations and in membrane reactors for hydrogen production from gasified coal and biomass. Amorphous Ni42Nb28Zr30 alloy membranes with the substitution of other elements such as Co or other elements for Ni (Ni32Nb28Zr30Co10) were prepared by melt spinning and then sputtered with a thin (500 nm) layer of Pd surface catalyst. Decreases in hydrogen flux were observed at higher temperatures (up to 450°C) during long-term hydrogen permeability tests. For example, Co increased the thermal stability of the membrane, but decreased its hydrogen permeability. Membranes were characterized by using SEM/EDX, XRD, TEM and AES sputter depth profiles to study the changes in surface and bulk microstructure and composition after testing. The decrease in hydrogen flux over time was attributed to a combination of metallic interdiffusion between the surface coating and the underlying membrane alloy and changes in membrane structure.