Thermo-mechanical properties of Zircon and Zircon-mullite composite

In recent years, mullite has drawn great attention because of its extraordinarily high temperature strength, creep resistance, chemical stability and low thermal expansion coefficient. Its mechanical properties at room temperature like fracture toughness are unfortunately very poor compared with other oxide materials like alumina and zirconia. Zircon-based materials enjoy wide application across different industries, especially steel, due to their superior properties at high temperature. Researchers are interested in using zirconia-mullite-based materials instead of zircon alone to combine the best aspects of both materials. Extensive research on the properties of zircon, zirconia, mullite and their ceramic composites has been carried out in the field of refractory applications. Zircon- mullite (ZRM) composite has been prepared in a variety of compositions by reaction sintering starting with different proportions of zircon. The effect of varying zircon percentage on densification, phase analysis and strength was measured. Thermal and thermo-mechanical properties (e.g. RUL, TSR, HMOR, RTE and PLC) were studied as a function of zirconia content. Phase analysis of zirconia-mullite-based composites showed the presence of free zircon which can provide better performance properties at high temperature. The formation of mullite phase improved both thermal shock and HMOR compared to non-mullite-based zircon and zircon- zirconia composites. © 2013 Expert Fachmedien GmbH.