Thermal shock behavior of pressureless liquid phase sintered SiC ceramics

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• 作者：Hanqin Liang ; Xiumin Yao ; ^{xmyao@mail.sic.ac.cn" class="auth_mail" title="E-mail the corresponding author} ; Zhengren Huang ; ^{zhrhuang@mail.sic.ac.cn" class="auth_mail" title="E-mail the corresponding author} ; Yuping Zeng ; Bizhe Su
• 关键词：D. SiC ; Liquid phase sintering ; Oxidation ; Thermal shock
• 刊名：Ceramics International
• 出版年：2016
• 出版时间：15 May 2016
• 年：2016
• 卷：42
• 期：7
• 页码：8677-8683
• 全文大小：2599 K

文摘

The thermal shock behavior of pressureless liquid phase sintered (PLPS) SiC ceramics with Al₂O₃ and Y₂O₃ as sintering additives was investigated by using water quenching method with the temperature difference from 200 °C to 1400 °C. It was found the residual flexural strength of PLPS SiC dropped quickly to about 100 MPa when the temperature difference reached 600 °C due to the cracks induced by thermal stress. The residual flexural strength of the PLPS SiC increased when the temperature difference reached 1300 °C and 1400 °C due to the formation of SiO₂ oxide layers, which acted as thermal barriers to reduce the thermal stress on the surface of the SiC ceramics. However, comparing the microstructure of specimens quenched at ΔT=1300 °C and 1400 °C, the slight decrease of residual flexural strength at ΔT=1400 °C was due to the formation of large amount of through pores in the oxide layer, which was speculated to be the strength-limiting flaw above 1300 °C.