Preparation of porous silica ceramics with relatively high strength by a TBA-based gel-casting method

Abstract

Porous silica ceramics with relatively high mechanical strength can be successfully fabricated via a novel tert-butyl alcohol-based gel-casting method. The microstructure similar to stone arch bridges and the sintering neck can be easily observed due to the evaporation of tert-butyl alcohol (TBA) during the drying process. The porosity of samples with different solid loading sintered at 1150°C varied within the range of 56.4% and 70.1%, as the bulk density from 0.67 to 1.04g/cm3. The compressive strength of sintered silica ceramics increased from 4.32MPa to 8.82MPa, which was attributed to the 3D-framework structure and the connection of silica particles. By setting the solid loading (15wt.%) and changing the sintering temperature from 1050 to 1200°C, the porosity of the sintered samples varied within the range of 51% and 72.4%, as the bulk density remarkably varied from 0.59 to 1.18g/cm3 and pore sizes from 3.31 to 2.89nm.