Centrifugal casting of alumina tube for membrane application

Alumina tubes of diameters 8 and 20 mm were successfully fabricated by centrifugal casting of a weakly-coagulated aqueous slurry in rotating tubular molds under accelerations of 28 and 70 times of gravitational acceleration, respectively. Due to differential settling during the casting, the microstructure was not uniform throughout the tubes but there was an indication of porosity-gradient through their thickness. This porosity-gradient might be beneficial for membrane application. We could control the porosity, pore size distribution and thus permeability of the tubes by varying particle size of starting alumina powders and controlling sintering temperature. This investigation demonstrates that centrifugal casting be a promising technique to fabricate alumina tubes for membrane application.