Microstructure, mechanical properties and thermal shock behavior of h-BN-SiC ceramic composites prepared by spark plasma sintering

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• 作者：Fengrui Zhai^a ; ^b ; Shuang Li^c ; Jialin Sun^a ; Zhongzhou Yi^b ; ^{yizhongzhou@tsinghua.org.cn}
• 关键词：h-BN-SiC ; Microstructure ; Mechanical properties ; Thermal shock behavior ; Spark plasma sintering
• 刊名：Ceramics International
• 出版年：2017
• 出版时间：1 February 2017
• 年：2017
• 卷：43
• 期：2
• 页码：2413-2417
• 全文大小：1569 K
• 卷排序：43

文摘

h-BN-SiC ceramic composites with different SiC contents were fabricated by spark plasma sintering. The results indicate that the addition of hard SiC particles has a remarkable effect on the densification, microstructure, mechanical properties and thermal shock resistance of the composites. Compared with pure h-BN ceramic, the relative density and mechanical properties of h-BN-SiC ceramic composites were improved obviously. The optimal properties of h-BN-SiC ceramic composites were obtained at SiC content of 25%, and the relative density, flexural strength and fracture toughness reached 97.8%, 289.2 MPa and 3.45 MPa m1/2, respectively. Moreover, the relationship of fracture toughness and fracture mode was discussed. The thermal shock test results showed that the h-BN-SiC ceramic composite with the SiC content of 25% exhibited excellent thermal shock resistance, presenting critical temperature difference up to 900 °C. The high temperature oxidation of h-BN and SiC on material surface led to the formation of borosilicate glass phase, which could heal the surface microcracks and then improve the thermal shock resistance.