Microstructure, mechanical properties and thermal shock resistance of zirconium diboride containing silicon carbide ceramic toughened by carbon black

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• 作者：Shanbao Zhou ; Zhi Wang ; Xin Sun ; Jiecai Han
• 关键词：ZrB₂ based ceramic ; Microstructure ; Mechanical properties
• 刊名：Materials Chemistry and Physics
• 出版年：2010
• 出版时间：1 August 2010
• 年：2010
• 卷：122
• 期：2-3
• 页码：470-473
• 全文大小：426 K

文摘

ZrB₂–20 vol. % SiC ultrahigh temperature ceramic containing 5 vol. % carbon black of nanometer size (ZSC) was prepared by hot-pressing at 1900 °C. The effect of carbon black addition on the microstructure and mechanical properties was investigated. Compared to the ZrB₂–SiC ceramics, the fracture toughness was significantly improved whereas flexural strength and hardness of the ZSC ceramic were slightly degraded. The fracture toughness as high as 6.6 ± 0.5 MPa m^1/2 was much higher than that of monolithic ZrB₂ (2.3–3.5 MPa m^1/2) and ZrB₂–SiC ceramics (4.0–4.5 MPa m^1/2). The toughening mechanisms were the crack deflection, bridging and branching. Furthermore, the effect of carbon black addition on the thermal shock resistance was systematically investigated and discussed.