Mechanical properties of borothermally synthesized zirconium diboride at elevated temperatures

The mechanical properties of a nominally phase pure ZrB2 ceramic were measured up to 2300°C in an argon atmosphere. was hot pressed at 2000°C utilizing borothermally synthesized powder from high purity ZrO2 and B raw materials. relative density the ceramics about 95% with average grain size 8.8 µm. room temperature flexural strength 447 MPa, decreasing 196 MPa 1800°C, then increasing 360 2300°C. 1800°C likely controlled by combination effects: surface damage oxidation specimens, stress relaxation, decreases elastic modulus. above flaws range consistent sizes maximum largest pores. Fracture toughness 2.3 MPa·m1/2 temperature, 3.1 2200°C. use higher starting materials improved behavior ultra-high regime compared previous studies.