A study on the preparation of CMAS glass-ceramics by in situ crystallization

Autores: Xiao, H.N.|Cheng, Y.|Yu, L.P.|Liu, H.B.
Fuente: Mater. sci. eng.
A 431 (1-2), 191-195
2006

Natural minerals and industrial slag are used as the starting materials for the preparation of glass-ceramics. Based on the glass system of CaO-MgO-Al2O3-SiO2 (CMAS), the CaO/MgO ratio, the kind and content of nucleating agent, the processing schedule for nucleation and crystallization on the microstructure and properties of the glass-ceramics were investigated. Results show that a dense and homogeneous glass-ceramics with a crystal size of about 50-200 nm was prepared using natural minerals only. The main phases of the glass-ceramics are wollastonite (beta-CaSiO3) and diopside (CaMg(SiO3)(2))(-) With the decrease of CaO/MgO ratio, the crystallizing temperature of the glass becomes higher, and the content of diopside increases. When CaF2 was used as nucleating agent, it results in a large number of nucleus by the phase separation in the glass and benefits the fine-grained microstructure of the glass-ceramics. The best mechanical properties of the glass-ceramics were obtained under the processing schedules of nucleation at 840º C and crystallization at 960º C.