Effect of zinc oxide on microhardness and sintering behavior of MgO-Al_2O_3-SiO_2 glass-ceramic system

摘要

Glass-ceramic in the MgO-Al_2O_3-SiO_2 system with crystallization ability of gahnite (ZnO-Al_2O_3) and mullite were synthesized. It was found that the glass-ceramic containing gahnite phase had desirable mechanical behavior and reached to an acceptable hardness and density. The compositions were designed based on magnesium oxide replacement (from MgO-Al_2O_3-SiO_2 glass-ceramic system) with zinc oxide. Glass-ceramics were characterized by DTA, X-ray diffraction and scanning electron microscopy. Heat treatment at 1100 °C cause form gahnite crystals in glass-ceramic. Microhardness increased with increasing gahnite crystals. To achieve good mechanical properties, the initially formed high gahnite phase must transform.