Mechanical Properties and Ablation Behavior of Machinable ZrB2-SiC-BN Ceramics
ZrB2-SiC-BN ultrahigh-temperature ceramic (UHTC) was fabricated by hot-pressing at 1800°C under 23MPa pressure of argon. Compared to ZrB2-SiC, the flexural strength of ZrB2-SiC-BN composite material was enhanced by adding 30% BN, and the fracture toughness showed a slight decrease, while the hardness decreased sharply. The addition of 30% BN also noticeably improved the machinability of the composites. Furthermore, ablation resistance tests were carried out using an oxyacetylene torch under subsonic conditions. Results indicated that a coherent compact scale of zirconium silicate was formed, which acted as an effective barrier against the inward diffusion of oxygen.
Yansheng Yin and Xin Wang
H. T. Wu and W. G. Zhang, "Mechanical Properties and Ablation Behavior of Machinable ZrB2-SiC-BN Ceramics", Advanced Materials Research, Vols. 79-82, pp. 2011-2014, 2009