Indexed on: 01 Sep '91Published on: 01 Sep '91Published in: Journal of Materials Science
The effect of ceria on mullite formation and the sintering of zircon and alumina powders was investigated. Quantitative X-ray powder analysis was used to determine the formation of mullite and zirconia of both monoclinic and tetragonal forms. Scanning electron microscopy and electron-probe microanalysis were used for microstructural analysis. It was found that the addition of CeO2 enhanced the formation of mullite and increased the fraction of tetragonal zirconia. The addition of CeO2 caused the formation of mullite directly from reaction of zircon with alumina without decomposition of zircon into zirconia and silica. In addition to forming a liquid phase, the ceria essentially formed a solid solution with zirconia. The fracture toughness of the mullite-zirconia composites was about 5.5–6.0 MPa m1/2.