Thermoelectric properties of porous SiC/C composites
Thermoelectric properties of porous SiC/C composites
复制标题
DOI：
10.1016/j.renene.2007.07.010
复制
发表时间：
2008-02
期刊：
影响因子：
8.7
通讯作者：
M. Fujisawa;T. Hata;H. Kitagawa;P. Bronsveld;Youki Suzuki;K. Hasezaki;Y. Noda;Y. Imamura
中科院分区：
文献类型：
--
作者：
M. Fujisawa;T. Hata;H. Kitagawa;P. Bronsveld;Youki Suzuki;K. Hasezaki;Y. Noda;Y. Imamura
我们通过在 N2 气氛下在 1600 和 1800°C 下脉冲电流烧结氧化由木炭和 SiO2（32-45μm）混合粉末制成的 SiC/C 复合材料，开发了多孔 SiC/C 复合材料。采用拉曼光谱和扫描电子显微镜（SEM）对氧化后的多孔SiC/C复合材料和未氧化的多孔SiC/C复合材料的微观结构进行了分析。拉曼光谱揭示了过量碳的消失和β-SiC的存在。通过SEM观察监测多孔微观结构作为热处理温度的函数。通过测量塞贝克系数、电导率和导热率，研究了氧化多孔SiC/C复合材料和未氧化SiC/C复合材料的热电性能。所有样品的塞贝克系数均表现为n型传导，且氧化后的多孔SiC/C样品的塞贝克系数绝对值远大于未氧化的SiC/C样品。未氧化的SiC/C样品的电导率大于氧化后的多孔SiC/C样品的电导率。另一方面，经过氧化处理的多孔SiC/C样品的热导率远低于未经氧化处理的SiC/C样品。一般来说，热电性能在较高的测量温度下得到改善，表明它们适合高温热电转换。在 1800°C 氧化烧结的多孔 SiC/C 样品中，在 700°C 时获得了 2.01×10−5K−1 的最大品质因数。
We developed a porous SiC/C composite by oxidizing a SiC/C composite made from a mixed powder of wood charcoal and SiO2(32–45μm) by pulse current sintering at 1600 and 1800°C under a N2atmosphere. The microstructures of the porous SiC/C composites with oxidation and the SiC/C composites without oxidation were analyzed by Raman spectroscopy and scanning electron microscopy (SEM). Raman spectra revealed the disappearance of excess carbon and the presence of β-SiC. The porous microstructure was monitored by SEM observation as a function of the heat treatment temperature. The thermoelectric properties of porous SiC/C composites with oxidation and SiC/C composites without oxidation were investigated by measuring the Seebeck coefficient, the electrical conductivity and thermal conductivity. The Seebeck coefficient of all samples revealed n-type conduction, and the absolute value of the Seebeck coefficient for the porous SiC/C samples with oxidation was much larger than that for the SiC/C samples without oxidation. The electrical conductivity of the SiC/C samples without oxidation was larger than that of porous SiC/C samples with oxidation. On the other hand, the thermal conductivity of porous SiC/C samples with oxidation was much lower than that of SiC/C samples without oxidation. In general, the thermoelectric properties improved at higher measurement temperatures indicating their suitability for high-temperature thermoelectric conversion. A maximum figure of merit of 2.01×10−5K−1was obtained at 700°C in porous SiC/C samples sintered at 1800°C with oxidation.