Effects of the Particle Size on the Microstructures and Liquid Absorbency of Silica Porous Ceramics

Porous silica ceramics are widely used as liquid transporters due to their desirable heat resistance, mechanical properties and chemical stability. In this work, we simulated the liquid absorbency and liquid permeation of samples with different pore sizes (such as 10, 20 and 40 mu m), and concluded that a large pore size is conducive to the liquid absorbency. Subsequently, porous silica ceramics were prepared through hot casting by using polymethyl methacrylate (PMMA) as a pore-forming agent. Experimental results showed that increasing the sintering temperature and reducing the heating rate would increase the pore size. Furthermore, the pore size increased with the increase of SiO2 and PMMA particle size, but inappropriate combination of particle size (such as 70 mu m PMMA and 20 mu m SiO2) resulted in an inhomogeneous pore structure. By testing the liquid absorbency of samples with different pore size (1.4, 6.8, 10.4, 14.2 and 20.4 mu m), we found that the liquid absorbency of the sample is correlated to the pore size. This study provides an experimental basis and theoretical guidance for the design and development of porous ceramics for liquid transport.