Abstract
The crystallization process of Li2O-SiO2 glass and lithium silicate gel powders has been investigated by means of differential thermal analysis, X-ray diffraction and infrared spectroscopy. The former was prepared by melting and contained 0.004-0.177wt% water and the latter, by hydrolyzing metal alkoxide solutions. It is found that with increasing water content in the glass, the glass transition temperature and the rate of nucleation decrease, whereas the rate of crystal growth increases. It is also found that gels prepared from a metal alkoxide solution show a crystallization process different from glasses prepared by conventional melting method; the crystalline phase precipitated from the former is metastable lithium metasilicate Li2SiO3 and that precipitated from the latter is stable lithium disilicate Li2Si2O5. It is also to be noted that the glass prepared by melting the gel shows a crystallization process similar to the glasses prepared by melting crystalline powders when their water contents are similar.
