Hot pressed ZrB2–SiC–C ultra high temperature ceramics with polycarbosilane as a precursor

ZrB2–SiC–C ultra high temperature ceramics (UHTCs) have been produced by hot pressing pyrolyzed mixtures of ZrB2 and polycarbosilane (PCS). Samples with SiC contents of 0%, 5% and 16% in volume derived from PCS were prepared. The phase composition, microstructure and mechanical properties were characterized for composites hot pressed at 2073 K for 60 min under the pressure of 20 MPa in an argon atmosphere. Analysis showed that the addition of PCS improved the relative density from 78% (without PCS addition) to ∼ 100% (with 16% SiC derived from PCS addition). Hardness and fracture toughness of the composite were also improved.