The nano-meter stainless steel powder was first deposited on porous stainless steel by paste coating process

and a micro-porous membrane with an average pore size of 200nm was obtained

its permeability for dry air was about 200cm3·cm-2·min-1 at room temperature and a pressure difference of 0.1 MPa. The micro-porous steel membrane was further coated with TiO2 membrane by Sol-Get method

and a composite membrane with pore size of 100nm was achieved

its permeability for dry air was about 100cm3·cm-2·min-1 at room temperature and 0.1 MPa. Then this membrane was electroless-plated to deposit Pd-Ag alloy

and a membrane with smooth surface and better alloy formation was obtained. The permeability of H2 for the Pd-Ag alloy membrane was about 35cm3·cm-2·min-1 under a normal condition of 0.1 MPa and 300℃

and the separation factor between H2 and He was about 500.