1-xSr xZn 2Si 2O 7 from BaO/SrO/ZnO/SiO 2 glass with different ZrO 2 and TiO 2 concentrations]]>

摘要

The effect of different nucleation agents such as ZrO2and TiO2was investigated for a first time with respect to their crystallisation behaviour in the glass system BaO-SrO-ZnO-SiO2. In all studied glasses, a Ba1-xSrxZn2Si2O7(0.1?≤?x?≤?0.9) solid solution crystallized. This phase was first described in 2015 to possess a similar structure as the high temperature phase of BaZn2Si2O7and a thermal expansion close to zero or even negative. It may find applications e.g. as cook panels, telescope mirrors, and furnace windows. Kinetic parameters of the crystallisation process were determined by supplying different heating rates in a differential scanning calorimeter (DSC). The results were evaluated using the equations of Ozawa and Kissinger with respect to the activation energies. Furthermore, the Ozawa method was used for the determination of Avrami parameters, which provides further information on the nucleation and crystallisation processes. Scanning electron microscopy including electron backscatter diffraction (EBSD) was used to characterise the microstructure, to determine the crystallite size and the crystal orientation. For the characterisation of the occurring crystalline phases, X-ray diffraction was used.