Investigation of a high stable beta-cristobalite ceramic powder from CaO-Al_2O_3-SiO_2 system

摘要

The room temperature stabilized beta-cristobalite ceramic powder has great potential for use in production of engineering ceramic materials due to its high resistance to thermal shock, low expansion coefficient, high chemical resistance and low density. However, the use of this material is not common in ceramic industries. The problem is shown to be the instability of beta-phase during milling. The applied external force leads to phase transformation to α-cristobalite and thus the material shows poor thermal stability and so on. In this study, a reliable beta-cristobalite ceramic powder from CaO-Al_2O_3-SiO_2 ternary system was investigated at different compositions and under various sintering temperatures and sintering times. The phase stability of the powder sample was investigated by milling for 50 h using a planetary mill. The crystalline phases were examined by X-ray and FTIR analysis and the results were discussed with respect to the phase homogeneity through the particle mass.