Studies on Crystallisation Behaviour of Certain Glass Compositions in the Systems Li2O-Al2O3-SiO2 and PbO-Al2O3-SiO2

Four glass compositions corresponding to Li2O.Al2O3.4SiO2, Li2O.Al2O3.6SiO2, PbO.Al2O3.2SiO2, and PbO.Al2O3.6SiO2, in the systems Li2O-Al2O3-SiO2 and PbO-Al2O3-SiO2 respectively were melted, and were subjected to DTA and X-ray analysis for varying heat treatment schedules, in order to observe their crystallisation behaviour.For glass compositions corresponding to PbO.Al2O3.2SiO2 and PbO.Al2O3.6SiO2, lead aluminium silicate (PbO.Al2O3.2SiO2)was the first phase to crystallise in all cases. Whereas for the glass corresponding to Li2O.Al2O3.6SiO2 composition, keatite was the only predominant phase crystallised. In the case of glass composition corresponding to Li2O. Al2O3.4SiO2, however, keatite solid solution with possible traces of Silica-O was present.