先驱体转化致密SiC纳米复合材料的制备及其热电性能

以聚碳硅烷和锑改性聚硅烷为先驱体，利用先驱体转化SiC材料的富余自由碳高温石墨化的微观结构演变特点，采用热压烧结、先驱体浸渍—裂解法以及退火工艺制备出先驱体转化SiC纳米复合材料。采用SEM、TEM、XRD和Raman等测试手段表征和分析了相组成和微观结构，讨论了样品的热导率、电导率和塞贝克系数等热电参数随温度变化关系。研究表明，所得致密SiC纳米复合材料为n型热电材料。由于纳米石墨的作用，材料热导率抑制在4–8W/(m?K)范围。1600°C退火处理能够降低热导率，同时提高电导率和塞贝克系数绝对值，使先驱体转化法得到的SiC纳米复合材料无量纲热电优值ZT达到0.0028（650°C），高于其他已报道的致密SiC/C复合材料和纳米复合材料体系。

Preparation and thermoelectric properties of polymer-derived dense SiC nanocomposites

Polymer-derived SiC nanocomposites were prepared by employing hot-press sintering, polymer infiltrating process and annealing, with polycarbosilane and antimony-modified polysilane as precursors. The phases and microstructures of samples were characterized and analyzed by using SEM, TEM, XRD and Raman spectroscopy. The thermoelectric parameters, thermal conductivity, electrical conductivity and Seebeck coefficient, were studied. Results show that the SiC nanocomposites are dense and n-type thermoelectric materials. The thermal conductivity reduced, and both the electrical conductivity and the Seebeck coefficient increased due to annealing at 1600°C. This results in the ZT value growing to 0.0028, which is higher than those of SiC/C composites or nanocomposites ever reported.