Paper péÉÅá~ä fëëìÉ Äó dìÉëí bÇáíçêëW lêÖ~åáÅ-íç-fåçêÖ~åáÅ`çåîÉêëáçå mêçÅÉëë Ñçê mçäóãÉê-aÉêáîÉÇ`Éê~ãáÅë d~ë mÉêãÉ~íáçå mêçéÉêíáÉë çÑ^ãçêéÜçìë pá`jÉãÄê~åÉë póåíÜÉëáòÉÇ Ñêçã mçäóÅ~êÄçëáä~åÉ ïáíÜçìí lñóÖÉå`ìêáåÖ mêçÅÉëë Amorphous silicon carbide SiC membranes with molecular sieving properties were successfully synthesized on the outer surface of a g-alumina g-Al 2 O 3 -coated a-alumina a-Al 2 O 3 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 8.1j10 ࢬ7 molऄm ࢬ2 ऄs ࢬ1 ऄPa ࢬ1 and the H 2 carbon dioxide CO 2 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 2.4j10 ࢬ7 molऄm ࢬ2 ऄs ࢬ1 ऄPa ࢬ1 , a HeH 2 permselectivity of 1.9 and a HeCO 2 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.

Paper péÉÅá~ä fëëìÉ Äó dìÉëí bÇáíçêëW lêÖ~åáÅ-íç-fåçêÖ~åáÅ`çåîÉêëáçå mêçÅÉëë Ñçê mçäóãÉê-aÉêáîÉÇ`Éê~ãáÅë içï qÉãéÉê~íìêÉ`êóëí~ääáò~íáçå _ÉÜ~îáçê çÑ apá P k Q Ñêçã qáaçéÉÇ ãçêéÜçìë páäáÅçå káíêáÇÉ aÉêáîÉÇ Ñêçã mçäóíáí~å~ëáä~ò~åÉë Si MAS NMR spectroscopic analyses revealed that, during the polymerceramics conversion process, the dehydrogenation reactions of the PHPS were apparently accelerated by the small amount of Ti-doping using TiNCH 3 2 4 . This could lead to enhancing the lower temperature formation of SiN 4 tetrahedral units necessary for the crystallization of a-Si 3 N 4 at 1273 K.