Effect of impregnation temperature and concentration of alumina sol on the properties of 3D printed silica ceramics

Due to the glass transition of molten quartz and the layer-by-layer 3D printing method, the strength of the finished ceramics is low. Therefore, it is necessary to find a suitable method to improve the mechanical properties of 3D printed silica ceramics used as casting molds for turbine blades. Vacuum impregnation is a very attractive method to introduce new phases into ceramic pores through liquid impregnation, thereby improving the mechanical properties of ceramic parts. In this study, 3D printed silica ceramics were impregnated with alumina sol, and the effect of impregnation temperature and concentration of alumina sol on the properties of the samples were investigated. The cristobalite content and mechanical properties of silica ceramics impregnated by alumina sol with different concentration and temperature were compared. The impregnation of alumina sol can promote the formation of cristobalite phase in the ceramics, and the appropriate amount of cristobalite can improve the mechanical properties of the ceramics. When the concentration of alumina is 15 wt% and the impregnation temperature is 60℃, the overall performance of alumina sol impregnated samples is the best, with a flexural strength of 22.70 ± 0.46 MPa, a bulk density of 1.70 ± 0.02 g /cm3, and a porosity of 25.89 ± 1.32 %.