Effect of SiC content on electrical, thermal and ablative properties of pressureless sintered ZrB₂-based ultrahigh temperature ceramic composites

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• 作者：Manab Mallik^a ; Ansu. J. Kailath^b ; K.K. Ray^c ; R. Mitra^c ; ^{rahul@metal.iitkgp.ernet.in" class="auth_mail" title="E-mail the corresponding author} ; ^{rahulmitra1966@gmail.com" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Borides ; Composites ; Electrical conductivity ; Thermal properties ; Ablation resistance
• 刊名：Journal of the European Ceramic Society
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：37
• 期：2
• 页码：559-572
• 全文大小：2495 K

文摘

The effects of SiC content (10–40 vol.%) on electrical, thermal and ablation properties of pressureless sintered ZrB₂-SiC composites showing interfacial segregation of W-rich phases have been studied. The electrical resistivity was measured by four-probe method, whereas thermal diffusivity and coefficient of thermal expansion (CTE) were determined using laser-flash method and thermo-mechanical analyzer, respectively. Whereas thermal conductivities calculated from experimentally obtained thermal diffusivity values are found to be the highest for the ZrB₂-20 SiC composite, both electrical conductivity and CTE decrease with increasing SiC content. The specimens were subjected to thermal shock by soaking at 800–1200 °C, followed by water-quenching. Further, some specimens were exposed to oxyacetylene flame (2200 °C) for 10 min. The damage was estimated from changes in mass, Young’s modulus, and hardness. The highest thermal shock and ablation resistance have been observed for the ZrB₂-20 SiC composite, as thermal properties and formation of protective oxide scale play key role.