The crystallization kinetics of the CaO-SiO2-P2O5-MgO-Al2O3 base glass system

In this study, the crystallization kinetics of CaO-SiO2-P2O5-MgO-Al2O3 glass was investigated. DTA analysis was employed to determine the glass transition and crystallization temperatures of the glass system. The crystallization heat treatment was realised at 825 °C and 1000 °C for 1 h based on DTA results. XRD analysis, by which whitlockite, anorthite, diopside, and wollastonite phases were detected, was performed for crystalline phase determination. The activation energies of crystallization and viscous flow were measured to be 328 kJ · mol− 1 and 377 kJ · mol− 1, indicating that bulk nucleation and two-dimensional crystal growth were the dominating mechanisms. Micro-structural investigations by using SEM analysis showed that the produced CaO-SiO2-P2O5-MgO-Al2O3 glass-ceramics exhibited a porous, fine, and homogenous microstructure. In addition, the glass and glass-ceramic samples were characterized by hardness and fracture toughness tests.