Highly permeable porous silicon carbide support tubes for the preparation of nanoporous inorganic membranes

Highly permeable and mechanically strong porous SiC tubular supports, used for the fabrication of nanoporous SiC membranes, are prepared by the pressureless sintering of β-SiC particles. Their transport characteristics are studied via inert gas (He and Ar) permeation tests, while their surface structure is characterized by atomic force microscopy and electron microscopy analysis. In this paper, the effects of the type of starting powders used and their composition, the sintering temperature, and the amount of sintering aids utilized on the transport characteristics and the surface roughness of the sintered SiC porous supports are systematically investigated. These tubular SiC supports exhibit very high fluxes (a He permeance as high as 5.8×10−5 mol m−2 Pa−1 s−1) and are mechanically strong to withstand the pressure drops required in their use as membrane supports. They have been used in the preparation of high quality SiC nanoporous membranes.