The Effect of Sintering Temperature on the Structure and Properties of Calcium Hexaluminate/anorthite Ceramics

摘要

The calcium hexaluminate/anorthite composite are prepared by magnesia slag, kaolin and industrial alumina at different sintering temperature. The effect of sintering temperature on the structure and properties are investigated by X-ray powder diffraction and scanning electron microscopy. The results show that the calcium hexaluminate begins to form at 1300 "C and continues to form in a large amount between 1400 °C and 1500 "C, however, there is a phase transitions form gehlenite to anorthite between 1300 °C and 1400 "C. CA6 grow preferentially along the basal plane direction. When the crystals touch each other, the CA_6 crystals turn to grow up along the axial direction. The apparent porosity decreases and bulk density increases and the flexural strength increases with the rising of the sintering temperature.