Yang Bo-lin,Kuang Chang-liu,Liu Zheng-long,Yu Chao,Deng Cheng-ji,Ding Jun
ZrB 2 -based ceramic composites were prepared by spark plasma sintering using ZrB 2 powder prepared by molten salt method as raw material and SiC and nano-graphite as additives. The effects of nano-graphite addition on the physical properties and oxidation resistance of ZrB 2 -based ceramic samples were investigated. The results show that the addition of an appropriate amount of nano-graphite can effectively improve the density of ZrB 2 -based ceramic composites and improve the physical properties of the materials. The flexural strength of the ceramic sample with 8 vol.% nano-graphite reached 418.54 MPa, which was 53.14% higher than that of ZrB 2 –SiC ceramic material (273.31 MPa), and its oxidation resistance was also significantly improved. It demonstrats that the addition of an appropriate amount of nano-graphite can effectively improve the physical properties and oxidation resistance of ZrB 2 –SiC ceramic composites. Via prolonging its service life in application and promoting the development of ZrB 2 -based ceramic composites, it is of great significance for clean steel smelting.
Reliable evaluation of the thermal shock behavior of complex-shaped components is very important for ultra-high temperature ceramics. Unfortunately progress in this field is hampered by a lack of available experimental methods. Here, a novel water spraying method is proposed to investigate the thermal shock behavior of ZrB 2 -based sharp leading edges (SLEs). Results indicated that the introduction of graphite flakes significantly improved the thermal shock resistance of ZrB 2 -SiC (ZS) SLEs. However, owing to the anisotropies of microstructure and thermal conductivity of ZrB 2 -SiC-G (ZSG) ceramic, the thermal shock resistance and the failure mode of ZSG SLEs were sensitive to the sampling orientation, which also were remarkably influenced by the size and/or shape of SLEs, leading to the variability of critical failure temperature from 750 °C to 375 °C and crack patterns from deflection to wave-shaped.
危险品化学品经营许可证（带存储）