Gas Permeation Properties of Amorphous SiC Membranes Synthesized from Polycarbosilane without Oxygen-Curing Process

Abstract

Amorphous silicon carbide (SiC) membranes with molecular sieving properties were successfully synthesized on the outer surface of a γ-alumina (γ-Al2O3)-coated α-alumina (α-Al2O3) porous support through pyrolysis of polycarbosilane without oxygen-curing process. The amorphous SiC membrane pyrolyzed at 1073 K after dip coating with capillary force possessed the hydrogen (H2) permeance of 8.1×10-7 mol•m-2•s-1•Pa-1 and the H2/carbon dioxide (CO2) permselectivity of 13 at 873 K. On the other hand, the amorphous SiC membrane pyrolyzed at 1073 K a total of four times after dip coating without capillary force possessed a helium (He) permeance of 2.4×10-7 mol•m-2•s-1•Pa-1, a He/H2 permselectivity of 1.9 and a He/CO2 permselectivity of 19 and at 873 K. Gas permeance properties were depended on coating method, densification of the Si-C network by heat history and film thickness.