Supported Alumina Members by an in-Situ Sol–Gel Method

Alumina membranes were prepared using a sol–gel process. Thin gel layers were grown onto porous alumina support tubes by using the permeation of water through the tube to control the rate of hydrolysis. Optimum coating conditions were found to be an ASB to 2-propanol volume ratio of 1:25, coating times between 10 and 15 s, and partial drying times between 2.5 and 3 min, depending on whether the water was flowing in the tube or stored in the tube. The coatings remained crack-free and adherent when fired to 800°C.