Preparation of SiC ceramics reinforced with in-situ generated mullite by microwave sintering.

Combining mullite with SiC ceramics is considered to be an effective method to reduce the sintering temperature of ceramics while maintaining excellent performance of the resultant materials. However, traditional heating methods used in this process are still more energy intensive. This work presents a fabrication method for producing mullite-bonded SiC ceramics via microwave heating and an in situ mullite reaction bonding. Via the proposed method, the preparation of samples with a bending strength of 125 ± 6 MPa and a porosity of 36.2% can be achieved at 1200 °C for 15 min. The microwave coupling effect and the impedance matching effect of SiC particles provide the heat source for the rapid sintering of the mullite-bonded SiC ceramics at low temperature. Bridging configuration of mullite between SiC particles occurred due to the unique coupling effects during microwave heating. Moreover, the low sintering temperature and short holding time inhibit the formation of the detrimental cristobalite phase. This work indicates that this rapid and low-temperature preparation method of mullite-bonded SiC ceramics has potential uses in the industrial production of high-performance SiC ceramics. [Display omitted] [ABSTRACT FROM AUTHOR]