Abstract
This study reports the preparation of laminated HfB2-SiC/SiCw ceramic (LHSw) with interfacial SiC whiskers (SiCw) by tape-casting followed by hot-pressing. The microstructure and mechanical properties of LHSw were studied in detail. The results showed that the flexural strength and fracture toughness of LHSw materials were 408 ± 24 MPa and 10.6 ± 0.4 MPa m1/2, respectively. The fracture toughness of the LHSw material was higher by 2.6 times than that of a monolithic HfB2-SiC ceramic (HS) (4.1 ± 0.2 MPa m1/2). This improvement was ascribed to the SiC whiskers with high aspect ratio in the interfacial layer, which was beneficial for the deflection and bifurcation of cracks. In addition, LHSw showed excellent resistance to thermal shock. It is found that the critical thermal shock temperature difference was approximately 553 °C, which is 1.2 times higher than that of HS (457 °C) and can be attributed to the porous structures formed in the interfacial layer of LHSw. Thus, micro-cracks formed in LHSw, but it was not penetrating cracks that formed in the HS after thermal shock.
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