Development of thin porous metal sheet as micro-filtration membrane and inorganic membrane support

A reactive material processing method is developed in this work for fabrication of thin (25–200 μm) porous metal sheets of sub-micrometer pore sizes. A green sheet is first prepared by tape-casting of metal oxide-loaded slurry. Then, the green sheet is converted into a porous metallic structure through a high-temperature reduction process. Detailed preparation processes and characterization results are delineated with Ni materials as examples. The resulting 50 μm-thick Ni sheet of about 50% porosity looks like a metal foil, which is strong enough to be self-supported and flexible to bending. The gas permeance and permeability, depending on the sheet thickness and preparation conditions, is ranged from 5.0 × 10−5 to 4.0 × 10−4 mol/(m2 Pa s) and from 1.5 × 107 to 8.5 × 107 Barrer, respectively. Such porous metal sheets may be used directly as a micro-filtration membrane or serve as an inorganic membrane support platform. This innovation makes it possible to develop thin flat sheet inorganic membranes with surface area packing density similar or comparable to polymeric membrane sheets.

► Thin (25–200 μm) porous Ni alloy sheets of sub-micrometer pores are prepared with uniform pore structures.
► Inexpensive metal oxide powder is used as the metal precursor.
► The preparation process is versatile for tailoring of sheet chemical and physical properties.
► The 50 μm-thick sheet shows gas permeance of 1.0 × 10−4 mol/(m2 Pa s) and water permeability of 10,000 L/m2/h/bar.