Using X-ray diffraction technology to study the crystal microstructure of the materials, Zhang can determine whether the materials show promise in terms of ductility. This provides a shortcut of sorts so that the team doesnt waste time on materials that are potentially brittle. A little more than a year into the project, about 60 binary alloys have been developed with additional ones in the planning stages. The results have been mixed, but Russell indicated one sample is quite promising and several others show promise.

"There have been surprises. Some alloys that you would expect to be ductile turn out to be hopelessly brittle, like glass," Russell said. "We also tried a material with 25 percent ruthenium, an element which is notorious for making alloys brittle, but that material turned out to be quite ductile." Samples produced in Ames are first cold rolled to see if they are ductile. Those showing promise are further tested and shipped to REB Research where theyre tested to determine how easily hydrogen will diffuse through the metal. Those showing promise get further testing to see if they can be formed into tubes and how they respond to heating and cooling cycles. But even those materials that are rejected as a palladium substitute, may ultimately wind up as useful for other purposes.

"I think weve got a good chance of finding something that works for hydrogen generation, but even if none of these alloys are good at that, the materials were working with will certainly have other applications." Buxbaum said. "One metal in particular is an amazing alloy shiny, ductile, high melting, and totally resistant to aqua regia (a mixture of nitric and hydrochloric acids that dissolves gold or platinum)."
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Contact: Kerry Gibson
kgibson@ameslab.gov
515-294-1405
DOE/Ames Laboratory
26-Mar-2007