V–Ni alloy membranes for hydrogen purification

Abstract In order to establish technical fundamentals for practical application of V–15%Ni alloy developed for hydrogen purification membrane, deformation behavior and hydrogen permeation performance of Pd-plated cold-rolled and unrolled samples have been examined. Once the solidification microstructure was refined by plastic works at high temperatures, cold rolling could be performed without any difficulty to produce thin strips. Pd-plated membranes machined from a cold-rolled sheet of V–15Ni alloy exhibited slight trapping behavior of hydrogen, resulting in a decrease in apparent hydrogen diffusivity and steady-state hydrogen permeability. Nevertheless, the hydrogen flux was observed to increase inversely in proportion to the thickness of the membrane due to a much greater influence of thinning on the permeation flow. The durability tests showed that hydrogen permeability decreased by 5% in 2 weeks at 573 K and 30% in 1 week at 473 K. The deteriorated permeability was recovered successfully by a baking treatment.