Ceramic sintering additives of CaO-MgO-SiO2 system

Using this system of sintering additives, alumina-based ceramics can be synthesized at about 1500-1550°C. MgO plays an important role in the fine crystal microstructure of alumina ceramics, and MgO can maintain the CaO/SiO2 ratio in sintering, i.e., maintain the amount of liquid phase in the sintering system, and a variety of second-phase crystals such as spinel, magnesium aluminosilicate, aluminosilicate, aluminate, etc. are generated, which have a spiking effect on grain boundary movement. Zapping effect, they effectively inhibit the grain growth; meanwhile, a small amount of rare earth oxides such as La2O3 and Sm2O3 are introduced to reduce the sintering temperature of Al2O3 ceramics by about 30°C and improve its surface microstructure, which is mainly due to the fact that La2O3 and Sm2O3 are network denaturing ions that can decompose the melt network and promote sintering.