Hydrogen Perm-Selectivity Property of the Palladium Hydrogen Separation Membranes on Porous Stainless Steel Support Manufactured by Metal Injection Molding

Pd-based membranes have been widely used in hydrogen purification and separation due to their high hydrogen diffusivity and infinite selectivity. However, it has been difficult to fabricate thin and dense Pd-based membranes on a porous stainless steel(PSS) support. In case of a conventional PSS support having the large size of surface pores, it was required to use complex surface treatment and thick Pd coating more than <TEX>6μm</TEX> on the PSS was required in order to form pore free surface. In this study, we could fabricate thin and dense Pd membrane with only <TEX>3μm</TEX> Pd layer on a new PSS support manufactured by metal injection molding(MIM). The PSS support had low surface roughness and mean pore size of <TEX>5μm</TEX>. Pd membrane were prepared by advanced Pd sputter deposition on the modified PSS support using fine polishing and YSZ vacuum filling surface treatment. At temperature <TEX>400∘C</TEX> and transmembrane pressure difference of 1 bar, hydrogen flux and selectivity of <TEX>H₂/N₂</TEX> were <TEX>11.22ml\;cm⁻²min⁻¹</TEX> and infinity, respectively. Comparing with <TEX>6μm</TEX> Pd membrane, <TEX>3μm</TEX> Pd membrane showed 2.5 times higher hydrogen flux which could be due to the decreased Pd layer thickness from <TEX>6μm</TEX> to <TEX>3μm</TEX> and an increased porosity. It was also found that pressure exponent was changed from 0.5 on <TEX>6μm</TEX> Pd membrane to 0.8 on <TEX>3μm</TEX> Pd membrane.