Highly dense β-SiC ceramics with submicron grains prepared by sintering of nanocrystalline powders

Highly dense β-SiC ceramics (99.1% TD) with an average grain size of <1 μm were prepared by hot pressing of nanocrystalline β-SiC powders. Large samples with a diameter of 150 mm were produced, showing a hardness of 24.9 ± 0.7 GPa and a fracture toughness of 4.4 ± 0.2 MPa m1/2. During the hot pressing, the densification was expected to be facilitated by the assistance of liquid and the high sinterability of the nanosized crystallites, and was little hindered by the high degree of agglomeration in the starting powder.