Crystallization and properties of a spodumene-willemite glass ceramic

Spodumene-willemite glass ceramics were produced by replacement of Al2O3 in lithium aluminium silicate by ZnO. With replacement of Al2O3 by ZnO, the batch melting temperature, glass transition temperature (Tg) and crystallization temperature (Tp) all decreased. The main crystalline phases precipitated were eucriptite, β-spodumene and willemite (Zn2SiO4). All compositions of glass ceramics showed bulk crystallization. As ZnO content increased, the grain sizes and thermal expansion coefficients increased, while the flexural strength and fracture toughness of the glass-ceramics increased first, and then decreased. The mechanical properties were correlated with crystallization and morphology of glass ceramics.