Power-Generation Characteristics After Vibration and Thermal Stresses of Thermoelectric Unicouples with CoSb3/Ti/Mo(Cu) Interfaces
Power-Generation Characteristics After Vibration and Thermal Stresses of Thermoelectric Unicouples with CoSb3/Ti/Mo(Cu) Interfaces
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DOI：
10.1007/s11664-015-3694-8
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发表时间：
2015-06-01
影响因子：
2.1
通讯作者：
Hwang, Hae Jin
中科院分区：
文献类型：
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作者：
Bae, Kwang Ho;Choi, Soon-Mok;Hwang, Hae Jin
对热电单电偶进行了可靠性测试，以研究 CoSb3/Ti/Mo(Cu) 界面的粘附性能。通过感应熔炼和放电等离子烧结工艺制备了 n 型 In-0.25 Co3.95Ni0.05Sb12 和 p 型 In0.25Co3FeSb12 块体，用于制造热电单电偶（一个 p-n 电偶）。由于其高熔化温度和适当的功函数值，Mo-Cu合金被选为单电偶的电极。许多具有 CoSb3/Ti/Mo(Cu) 界面的热电单电偶是使用适当的钎焊材料通过重复烧制工艺制造的。通过振动测试和热循环测试评估带有接口的单电偶的可靠性。经过热循环和振动测试后，将单电偶的发电特性与测试前的单电偶进行了比较。即使在振动测试之后，仍产生功率密度为0.5W/cm(2)的电力。钛中间层被认为是制造具有高粘合强度的可靠单电偶的可能候选材料。随着热循环测试，单电偶的电阻增加并且来自单电偶的电功率减少。热循环测试的失效模式归因于热电材料的热应力和氧化问题引起的微裂纹的复杂影响；即n型In0.25Co3.95Ni0.05Sb12材料在空气中773K高温耐久性试验7天后，检测到超过300μm的厚氧化层。
Reliability tests for thermoelectric unicouples were carried out to investigate the adhesion properties of CoSb3/Ti/Mo(Cu) interfaces. The n-type In-0.25 Co3.95Ni0.05Sb12 and p-type In0.25Co3FeSb12 bulks were prepared for fabricating a thermoelectric unicouple (one p-n couple) by an induction melting and a spark plasma sintering process. Mo-Cu alloy was selected as an electrode for the unicouples due to its high melting temperature and proper work function value. Many thermoelectric unicouples with the CoSb3/Ti/Mo(Cu) interfaces were fabricated with the proper brazing materials by means of a repeated firing process. Reliability of the unicouples with the interfaces was evaluated by a vibration test and a thermal cycling test. After the thermal cycling and vibration tests, the power-generation characteristics of the unicouples were compared with the unicouples before the tests. Even after the vibration test, electrical power with a power density of 0.5 W/cm(2) was generated. The Ti-interlayer is considered as a possible candidate for making a reliable unicouple with high adhesion strength. With the thermal cycling test, the resistance of the unicouple increased and the electrical power from the unicouple decreased. A failure mode by the thermal cycling test was ascribed to a complex effect of micro-cracks originated from the thermal stress and oxidation problem of the thermoelectric materials; that is, a thick oxide layer more than 300 mu m was detected after a high-temperature durability test of n-type In0.25Co3.95Ni0.05Sb12 material at 773 K in air for 7 days.