Effect of MgO on Crystallization and Properties of Anorthite Glass-ceramic Glaze

A series of anorthite-based glass-ceramic glazes with different MgO contents were prepared from kaolin, potash feldspar, quartz, light calcium carbonate and calcined talc, while the effects of MgO content on crystallization, melting properties, microhardness and transparency of the glass-ceramic glazes were studied by using XRD, SEM, EDS and microhardness instrument. When the MgO content was 1.00–2.00 wt.%, the crystalline phase species changed from anorthite and α-pseudowollastonite coexisting with single-phase anorthite. When the MgO content increased from 3.00 wt.% to 5.00 wt.%, the main crystalline phase was still anorthite and the second phase was diopside. In addition, the content of diopside gradually increased. As the MgO content increased from 0.15 wt.% to 5.00 wt.%, the melting properties and transparency of glass-ceramic glazes increased first and then decreased, while the microhardness gradually increased. When the MgO content was 3.00 wt.%, plate-like anorthite with a content of 26.87% precipitated from the glaze and the glaze had excellent transparency and a microhardness of 5.26 GPa.