The H permeation of thin Pd-25Ag membranes, with thicknesses down to 1.2μm, was investigated by using conventional gas permeation methods at 473 to 673K. Thin Pd-25Ag membranes, with thicknesses down to 51μm, were prepared by cold-rolling. The 1.2μm-thick Pd-25Ag membrane was prepared by microsystem technology. The H permeation of the prepared Pd-25Ag membranes was independent of the membrane thickness, down to 51μm. The 51μm-thick Pd-25Ag membrane had a H permeability which was lower, by 60%, than that of the bulk Pd-25Ag metal. This resulted mainly from a slow surface reaction and lower H solubility near to the surface of the 51μm-thick Pd-25Ag membrane. The H permeability of the 1.2μm-thick Pd-25Ag membrane was an order lower than that of bulk Pd-25Ag metal because the H permeation was limited mainly by surface reactions. However, a literature review indicated that the micro-fabricated 1.2μm-thick Pd-25Ag membrane had a H permeability which was superior to that of conventional Pd-25Ag membranes supported by porous materials.

Hydrogen Permeation of Thin Pd-25Ag Membranes Prepared by Cold Rolling and Microsystem Technology. Y.Zhang, J.Lu, R.Maeda, C.Nishimura: Materials Transactions, 2008, 49[4], 754-9