Effect of Mineralizers on Sintering Properties of MgO-Al2O3-SiO2 Composite Ceramics

Abstract

MgO-Al2O3-SiO2 composite ceramics are widely used in high-temperature filter materials, refractories, catalyst carrier materials and insulating materials because of their low coefficient of thermal expansion, good high-temperature stability and mechanical properties. In the process of preparing MgO-Al2O3-SiO2 composite ceramics, it is more important to select a suitable mineralizer in order to effectively reduce the sintering temperature of MgO-Al2O3-SiO2 composite ceramics and improve the properties of MgO-Al2O3-SiO2 composite ceramics. In this experiment, 97 grade fused magnesia, Al2O3 powder and ferrosilicon ash powder were used as main raw materials. Meanwhile, Cr2O3 powder, ZrO2 powder and TiO2 powder were selected as mineralizers. MgO-Al2O3-SiO2 composite ceramics were prepared by the semi-dry pressing method. The effects of different mineralizers on the sintering properties of MgO-Al2O3-SiO2 composite ceramics were studied. The experimental results show that the addition of Cr2O3 powder cannot promote the sintering of MgO-Al2O3-SiO2 composite ceramics and the addition of TiO2 powder and TiO2 powder can promote the sintering of MgO-Al2O3-SiO2 composite ceramics. Moreover, the sintering performance of MgO-Al2O3-SiO2 composite ceramics is better than that of MgO-Al2O3-SiO2 powder. When the addition of ZrO2 powder is 4%, it can promote the formation of periclase phase, refine grains and play a toughening effect, and the bending strength of MgO-Al2O3-SiO2 composite ceramics reaches the maximum value of 19.3 MPa.