The effect of sintering temperature on the structure and properties of calcium hexaluminate/anorthite ceramics

Abstract

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 CA6 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.