Preparation and sintering properties of zirconia-mullite-corundum composites using fly ash and zircon

Zirconia-mullite-corundum composites were successfully prepared from fly ash, zircon and alumina powder by a reaction sintering process. The phase and microstructure evolutions of the composite synthesized at desired temperatures of 1 400, 1 500 and 1 600 degrees C for 4 h were characterized by X-ray diffractometry and scanning electronic microscopy, respectively. The influences of sintering temperature on shrinkage ratio, apparent porosity and bulk density of the synthesized composite were investigated. The formation process of the composites was discussed in detail. The results show that the zirconia-mullite-corundum composites with good sintering properties can be prepared at 1 600 degrees C for 4 h. Zirconia particles can be homogeneously distributed in mullite matrix, and the zirconia particles are around 5 mu m. The formation process of zirconia-mullite-corundum composites consists of decomposition of zircon and mullitization process.