Heating microscopy study of the sintering behaviour of glass powder compacts in the binary system SiO2-TiO2

Glass powders in the binary glass-forming SiO2-TiO2 system were synthesized by very slow hydrolysis of metal alkoxides using sol-gel process. The sintering behaviour of calcined glass powders was investigated using heating microscopy. Both the densification and crystallisation stages were studied. It was found that the sintering temperature, T-sin, and the crystallisation temperature, T-cry, decrease by increasing TiO2 content, in agreement with previous results from dilatometry studies. Slightly but consistent higher T-sin values were measured using heating microscopy in comparison with dilatometer data. The results confirm that heating microscopy is a useful, non-invasive technique to study sintering and crystallisation phenomena in glass powder compacts, presenting some advantages over dilatometry, especially the absence of a compressive load acting on the sample during the experiment. (C) 2002 Elsevier Science B.V. All rights reserved.