Sintering and crystallization of (SrO center dot SiO2)-(SrO center dot Al2O3 center dot 2SiO(2)) glass-ceramics

In the ternary SrO-Al2O3-SiO2 system the pseudobinary join composition of 5 0 wt % SrO . SiO2-50 wt % SrO . Al2O3. 2SiO(2) (SS-SA2S) showed a glass mel ting temperature of similar to 1500 degrees C and a crystallization peak te mperature of similar to 1100 degrees C. The (SS-SA2S) glass-ceramic pellets prepared by cold pressing and pressureless sintering, showed very low poro sity. The (SS-SA2S) glass-ceramics containing B2O3 and those containing B2O 3 and TiO2 revealed crystallization peak temperatures of similar to 1000 de grees C and unexpectedly high porosity. By applying Kissinger analyses to t he DTA data the activation energy values for crystallization of the three g lass-ceramics were determined to range from 196 to 255 kJ/mol. The Ozawa an alyses on the DTA data gave the Avrami parameter values at 3.69 to 3.95. Th e X-ray diffraction (XRD) patterns from the three glass-ceramics revealed f ormation of the equilibrium crystalline phases of SrO . SiO2 and SrO . Al2O 3. 2SiO(2) (monocelsian). (C) 1999 Kluwer Academic Publishers.