The effects of compositional variation, nucleationcatalyst and thermal treatment on the nature, type and stability field ofcrystallizing phases and microstructure formed in CaO and/or MgO aluminosilicateglasses are described using differential thermal analysis (DTA), X-ray powderdiffractometry (XRD) and scanning electron microscopy (SEM). Wollastonite solidsolution was formed in calcium aluminosilicate glass-ceramics, however, with MgOreplacing CaO, pyroxene solid solution was developed. The addition of thenucleants brings varieties of aluminosilicate phases e.g., plagioclase, meliliteand spodumene developed together with fluorite, fluorosilicate and/or TiO2-bearingphases. Intense uniform bulk crystallization with fine-grained microstructurewas achieved by an addition of TiO2 or CaF2 rather than LiF. The role of thenucleating agents during the formation of the crystal phases and themicrostructure of the resultant glass-ceramics are discussed.
