A strategy to optimize the thermoelectric performance in a spark plasma sintering process.
A strategy to optimize the thermoelectric performance in a spark plasma sintering process.
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DOI：
10.1038/srep23143
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发表时间：
2016-03-15
影响因子：
4.6
通讯作者：
Chen YY
中科院分区：
文献类型：
--
作者：
Chiu WT;Chen CL;Chen YY
放电等离子烧结（SPS）目前广泛应用于现有的合金作为进一步提高合金的品质因数的手段。然而，最佳烧结条件的确定是具有挑战性的SPS过程。该报告展示了一种系统的方法来独立优化塞贝克系数S和电导率与热导率之比（σ/κ），从而实现最大品质因数zT = S2（σ/κ）T。以Sb 2 − xInxTe 3（x = 0-0.2）为例进行了验证。虽然高烧结温度和压力有助于提高压制样品的致密性和导电性，但由此产生的恶化的塞贝克系数和增加的热导率最终抵消了益处。我们发现，最佳烧结温度与最大塞贝克系数开始下降的温度相一致，而最佳烧结压力与σ/κ比达到最大值的压力相一致。根据这一原理，确定了最佳烧结条件，使Sb 1.9In 0.1Te 3的zT在600 K时提高到0.92，提高了约84%。这项工作开发了一个简单的策略，选择最佳的SPS烧结条件，以进一步提高批量试样的zT。
Spark plasma sintering (SPS) is currently widely applied to existing alloys as a means of further enhancing the alloys’ figure of merit. However, the determination of the optimal sintering condition is challenging in the SPS process. This report demonstrates a systematic way to independently optimize the Seebeck coefficient S and the ratio of electrical to thermal conductivity (σ/κ) and thus achieve the maximum figure of merit zT = S2(σ/κ)T. Sb2−xInxTe3 (x = 0–0.2) were chosen as examples to validate the method. Although high sintering temperature and pressure are helpful in enhancing the compactness and electrical conductivity of pressed samples, the resultant deteriorated Seebeck coefficient and increasing thermal conductivity eventually offset the benefit. We found that the optimal sintering temperature coincides with temperatures at which the maximum Seebeck coefficient begins to degrade, whereas the optimal sintering pressure coincided with the pressure at which the σ/κ ratio reaches a maximum. Based on this principle, the optimized sintering conditions were determined, and the zT of Sb1.9In0.1Te3 is raised to 0.92 at 600 K, showing an approximately 84% enhancement. This work develops a facile strategy for selecting the optimal SPS sintering condition to further enhance the zT of bulk specimens.