Microstructural Study on the Low Density SiO_2 Soot Body

摘要

Low density SiO_2 soot body, with a certain strength and porosity, is an intermediate of silica glass prepared by the indirect synthetic method. The microstructures of SiO_2 soot body have an important influence on the post-sintering process, such as micro-morphologies, pore structures and so on. In this paper, these microstructures, including micro-morphologies, phase structure, hydroxyl structure, pore structure, pore size distribution and specific surface area, were studied by ESEM, XRD, FTIR, mercury intrusion method and nitrogen adsorption method. Experimental results indicate that, the low density SiO_2 soot body is composed of amorphous nano-SiO_2 particles with a particle diameter distribution of 100nm ~ 150nm. The pore structure of SiO_2 soot body tends to be irregular and the pore shape contains cross-linked holes, through-holes and blind holes. The pore size distribution is wide and involves macropore, mesopore and micropore.