Development of a new porous metal support of metallic dense membrane for hydrogen separation

Porous nickel support was successfully made by uniaxial pressing of nickel powder for gases separation or metal support of Pd and/or Pd-alloy dense membrane. Since the used nickel powder was prepared by pulsed wire evaporation (PWE) method, it has a good thermal stability. Furthermore, a broad particle size distribution from 20 to 5000 nm cleared out the powder mixing step in the procedures of fabrication of porous nickel support. From the pore characterization and SEM analysis, it was clarified that the fabricated porous nickel support had so small uniform pore size of 33 nm and very smooth surface so that it can be offered as new material for the substrate of palladium and/or palladium-based alloy membrane. As a result of single gas permeation test using H₂ and N₂, permeance was constant with increasing transmembrane pressure difference and the selectivity was around 3.7, which indicated that the gas permeation was contributed by Knudsen diffusion. Since it has thermal resistance up to 650 °C, sputtering followed by cupper reflow could be applied to the formation of Pd-Cu-Ni ternary film on it. Furthermore, it showed the defect-free dense membrane characteristic.