MICROSTRUCTURAL EVOLUTION OF TIO2-DOPED SILICA-GELS DURING HEATING

Properties of silica glass, doped with TiO2, obtained by the sol-gel t echnique were examined as depending on the heating method, using the m icrostructural investigation methods It has been found that the greate st specific surface and porosity are obtained immediately after the re moval of water and organic substances at the temperature of about 300 degrees C. With increasing heating temperature the specific surface an d the porosity decrease, especially above 900 degrees C. The mode the pores are linked with each other is also changed. The pores assume the character of ''through-pores''. open at both ends, and their closing takes place only with the lapse of time. The heating rate does not exe rt any essential influence on the product properties after heating, ne vertheless slow heating favours the preservation of the primary micros tructure of gel.