Crystallization and microstructure of CaO-MgO-Al2O3-SiO2 glass-ceramics containing complex nucleation agents

The CaO-MgO-Al2O3-SiO2 (CMAS)-glass-ceramics containing binary complex nucleation agents were prepared by body crystallization process, and the effects of complex nucleation agents on the crystallization and microstructure of CMAS glass-ceramics were investigated by differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The complex nucleation agents consist of constant fluorine (8.0 wt.% CaF2) and different oxides (3.0 wt.% TiO2, ZrO2, or P2O5). Compared with the CMAS glass with only CaF2, the respective addition of oxides promotes the crystallization of CMAS glass, especially TiO2 or P2O5. The addition of TiO2 or ZrO2 has no obvious effect on the compositions of main crystalline phases, while P2O5 results in the precipitation of pyroxene phase instead of diopside phase, with the existence of more small crystals. The CMAS glass-ceramic containing CaF2 + TiO2 or CaF2 + P2O5 achieves full body crystallization with high crystallization ratio, and has high hardness, good chemical resistance and water absorption. (C) 2014 Elsevier B.V. All rights reserved.