Gas permeation properties of amorphous SiC membranes synthesized from polycarbosilane without oxygen-curing process

Amorphous silicon carbide (SiC) membranes with molecular sieving properties were successfully synthesized on the outer surface of a gamma-alumina (gamma-Al2O3)-coated alpha 2-alumina (alpha-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 (H-2) permeance of 8.1 x 10(-7) mol center dot m(-2) center dot s(-1) center dot Pa-1 and the H-2/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 x 10(-7) mol center dot m(-2) center dot s(-1) center dot Pa-1, a He/H-2 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.