Abstract The effects of initial particle size and sintering atmosphere on the compressive strength and thermal and electrical conductivities of porous SiC ceramics, fabricated using α-SiC and polycarbosilane (PCS), were investigated in the porosity range of 40–54%. Generally, the mechanical strength and thermal conductivity of a porous SiC ceramic decrease as the porosity increases. However, in this study, both the compressive strength (10.7–17.4 MPa) and thermal conductivity (0.55–0.79 W/mK) of porous SiC ceramics increased as the porosity increased from 40 to 54% because of the decreased pore size (1013–218 nm) and increased bonding area per unit volume as the starting particle size decreased (35–1 μm). The influence of sintering atmosphere on the compressive strength and thermal conductivity of the porous SiC ceramics was negligible, whereas the porous SiC ceramics sintered in N2 atmosphere exhibited 4–10 times higher electrical conductivities than those of the samples sintered in Ar atmosphere, which can be attributed to N doping in the PCS-derived β-SiC. These results suggest that the mechanical, thermal, and electrical properties of porous SiC ceramics can be independently tuned to a certain extent by judiciously selecting the starting particle size and sintering atmosphere. The compressive strength, thermal and electrical conductivities, and porosity of the porous SiC ceramic processed with 35 μm particles in the N2 atmosphere were 10.7 MPa, 0.58 W/(m·K), 2.2 × 10−3 Ω−1·cm−1, and 40.3%, respectively.

中文翻译：

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初始粒径对多孔 SiC 陶瓷力学、热学和电学性能的影响

摘要 在 40-54% 的孔隙率范围内研究了初始粒径和烧结气氛对使用 α-SiC 和聚碳硅烷 (PCS) 制备的多孔 SiC 陶瓷的抗压强度和热导率和电导率的影响。通常，多孔 SiC 陶瓷的机械强度和热导率随着孔隙率的增加而降低。然而，在本研究中，多孔 SiC 陶瓷的压缩强度 (10.7-17.4 MPa) 和热导率 (0.55-0.79 W/mK) 都随着孔隙率从 40% 增加到 54% 而增加，因为孔径减小 (1013- 218 nm），随着起始粒径的减小（35-1 μm），每单位体积的键合面积增加。烧结气氛对多孔碳化硅陶瓷的抗压强度和热导率的影响可以忽略不计，而在 N2 气氛中烧结的多孔 SiC 陶瓷的电导率比在 Ar 气氛中烧结的样品高 4-10 倍，这可归因于 PCS 衍生的 β-SiC 中的 N 掺杂。这些结果表明，通过明智地选择起始粒径和烧结气氛，可以在一定程度上独立调节多孔 SiC 陶瓷的机械、热和电性能。在 N2 气氛中用 35 μm 颗粒处理的多孔 SiC 陶瓷的抗压强度、热导率和电导率以及孔隙率为 10.7 MPa, 0.58 W/(m·K), 2.2 × 10−3 Ω−1·cm−1和 40.3%，分别。这可以归因于 PCS 衍生的 β-SiC 中的 N 掺杂。这些结果表明，通过明智地选择起始粒径和烧结气氛，可以在一定程度上独立调节多孔 SiC 陶瓷的机械、热和电性能。在 N2 气氛中用 35 μm 颗粒处理的多孔 SiC 陶瓷的抗压强度、热导率和电导率以及孔隙率为 10.7 MPa, 0.58 W/(m·K), 2.2 × 10−3 Ω−1·cm−1和 40.3%，分别。这可以归因于 PCS 衍生的 β-SiC 中的 N 掺杂。这些结果表明，通过明智地选择起始粒径和烧结气氛，可以在一定程度上独立调节多孔 SiC 陶瓷的机械、热和电性能。在 N2 气氛中用 35 μm 颗粒处理的多孔 SiC 陶瓷的抗压强度、热导率和电导率以及孔隙率为 10.7 MPa, 0.58 W/(m·K), 2.2 × 10−3 Ω−1·cm−1和 40.3%，分别。