摘要
A base glass of composition 3.5 Li2O鈭?.15 Na2O鈭?.2 K2O鈭?.15 MgO鈭?.8 BaO鈭?.5 ZnO鈭?0 Al2O3鈭?7.2 SiO2鈭?.6 TiO2鈭?.7 ZrO2鈭?.2 As2O3 (in wt.%), melted and provided by SCHOTT AG (Mainz), was used to study the crystallisation mechanism of lithium alumino-silicate glass employing X-ray diffraction combined with neutron diffraction and non-isothermal differential scanning calorimetry (DSC). A high-quartz solid solution of LiAlSi2O6 with nanoscaled crystals forms at 750 掳C. Quantitative Rietveld refinement of samples annealed at 750 掳C for 8 h determined a crystallised fraction of around 59 wt.%. The room temperature crystallised phase adopts an ordered, 尾-eucryptite-like structure (2 脳 2 脳 2 cell) with Li ordered in the structural channels. The Avrami parameter (n 鈭?4), calculated from DSC data using different theoretical approaches, indicates that bulk crystallisation occurs and that the number of nuclei increases during annealing. The activation energy of the crystallisation is 531 卤 20 kJ mol鈭?.