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中国物理学会期刊

强织构p型Bi0.5Sb1.5Te3材料的熔体旋甩快速烧结制备与热电性能研究

Fabrication and Thermoelectric Properties of Highly Textured p-type Bi0.5Sb1.5Te3 via Melt Spinning and Spark Plasma Sintering

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  • 传统区熔制备的Bi2Te3基材料力学性能较差,尽管粉末冶金热挤压制备技术有效改善了材料的力学性能,但其包括制粉、烧结、热挤压等工序,工艺流程冗长,严重制约了多晶Bi2Te3基材料的发展及其在微型热电器件的应用。本研究采用熔体旋甩方法制备p型Bi2Te3基薄带材料,然后通过直接平铺结合放电等离子活化烧结制备了系列高织构p型Bi2Te3基块体材料。熔体旋甩制备的薄带具有强的织构、丰富纳米结构和缺陷结构,采用不研磨平铺直接快速放电等离子活化烧结有效保留了薄带的取向特征,获得与传统球磨制粉放电等离子活化烧结不一样的沿垂直烧结压力方向强(1 1 0)织构特征,743 K烧结样品取向因子与热挤压样品基本相当,(1 1 0)面取向因子达到0.37。由于这种强取向特征,样品在平行于压力方向上获得了优异的电传输性能,室温下功率因子达到3.79 mW m-1 K-2,此外晶粒细化显著降低了材料的热导率,最终743 K烧结样品在398 K下获得了最高ZT值为1.30,相较于传统区熔样品提升了46%。本研究开发出一种快速、便捷的制备策略,用以合成具备强织构、细晶粒特征的高性能Bi2Te3基热电材料,为该类材料在微型热电器件领域的技术转化与部署奠定了重要基础。

     

    Bi2Te3-based materials prepared by traditional zone melting often suffer fro m poor mechanical properties. Although powder metallurgy followed by hot ext rusion can effectively enhance mechanical strength, this approach involves a len gthy, multi-step processes including powdering, sintering, and extrusion. Such a complex procedure has hindered the development of polycrystalline Bi2Te3-bas ed materials and their application in micro-thermoelectric devices. In this work, p-type Bi2Te3-based ribbons were first fabricated via melt spinning. Subsequent ly, a series of highly textured, fine-grained p-type Bi2Te3-based bulk materials were prepared by directly tiling these ribbons and consolidating them through Spark Plasma Sintering (SPS). The as-spun ribbons possess a strong texture, al ong with abundant nanostructures and defects. The subsequent consolidation, ac hieved by directly tiling these ribbons and applying Spark Plasma Sintering (SPS) without any pulverization, effectively preserved their intrinsic preferred orie ntation. This resulted in a strong (1 1 0) texture perpendicular to the pressing direction, which is distinct from that obtained via the conventional ball-milling and SPS route. The sample sintered at 743 K exhibited an orientation factor of 0.37, comparable to that of hot-extruded counterparts. Owing to this strong te xture, the sample exhibited superior electrical transport properties along the dire ction parallel to the pressure. A high power factor of 3.79 mW m-1 K-2 was ac hieved at room temperature. Furthermore, grain refinement led to a significant reduction in thermal conductivity. Consequently, a peak ZT value of 1.30 was obtained at 398 K for the sample sintered at 743 K, representing a 46% enhan cement over traditional zone-melted samples. This study provides a rapid and f acile strategy for fabricating highly textured, fine-grained, high-performance Bi2 Te3-based materials, laying a solid foundation for their engineering applications in Micro-thermoelectric devices.

     

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