Ultrahigh-Temperature Ceramic Based on ZrB 2 –SiC: Preparation and Main Properties

Hot pressing of commercially available powders is used to prepare dense ceramic based on ZrB 2 –SiC with different additives (Si 3 N 4 , TiSi 2 , ZrSi 2 , MoSi 2 ). The main physicomechanical properties are measured in macro-specimens: ultimate strength in static three-point bending at room temperature 400 – 600 MPa, Vickers microhardness up to 15 GPa, and critical stress intensity factor up to 5.9 MPa·m 1/2 . Average LTEC, thermal diffusivity, thermal conductivity, and oxidation resistance over a wide temperature range are determined. Altogether the ceramic properties obtained are at the level of published indices.