Preparation of Waterproof Silica Gel Coatings on Porous Silica Ceramic Substrates

摘要

Porous silica ceramic substrates were coated with silica sols via dip coating to obtain waterproof performance. Silica sols were prepared through acid-catalyzed hydrolysis and condensation of tetraethyl orthosilicate. The gelation temperature, ratio of ethanol/TEOS, times of coating, and sintering temperature have been studied. The sample with the best waterproof effect was prepared by 5 times of repeated coating using a sol prepared at 25 °C with an ethanol/TEOS ratio of 7 and sintering at 550 °C.