Nearly dense cordierite bonded silicon carbide ceramics prepared by hot pressing sintering at 1650°C

Cordierite bonded silicon carbide ceramics with different cordierite content were prepared by hot pressing sintering at 1650 °C. The samples with more than 30 wt% cordierite were nearly dense with relative densities greater than 99%. Cordierite existed in amorphous form, and was closely bound to SiC grains without transition layer, which resulted in the excellent mechanical properties of the composites. The sample with 30 wt% cordierite showed the best mechanical properties, with flexural strength of 411.44 ± 27.63 MPa, fracture toughness of 5.01 ± 0.54 MPa m1/2 and Vickers hardness of 12.02 ± 0.25 GPa, respectively. In addition, cordierite could effectively improve the infrared radiation performance of SiC ceramics, that the total emissivity of the sample with 40 wt% cordierite was 0.726, which was 16.5% higher than pure SiC ceramics.