Ni/Bi_(0.4)Sb_(1.6)Te_(3)热电材料的界面性能

Interface performance of Ni/Bi_(0.4)Sb_(1.6)Te_(3) thermoelectric material

Bi_(0.4)Sb_(1.6)Te_(3)热电材料和金属电极之间的阻挡层是热电器件稳定服役的控制性因素,本文以不同温度下退火后的高致密Ni箔和Bi_(0.4)Sb_(1.6)Te_(3)合金为原料,采用放电等离子烧结扩散焊连接法在Bi_(0.4)Sb_(1.6)Te_(3)表面制备Ni层作为Ni/Bi_(0.4)Sb_(1.6)Te_(3)电极接头的阻挡层。采用X射线衍射仪对阻挡层进行物相分析,用扫描电镜及能谱仪观察和分析电极接头的界面形貌与元素分布。结果表明,在700℃退火后的Ni箔具有优良的防扩散效果,扩散厚度为9μm,用700℃退火后的Ni箔与Bi_(0.4)Sb_(1.6)Te_(3)扩散焊结合,获得13.19 MPa的结合强度。随Ni箔的退火温度升高,Ni/Bi_(0.4)Sb_(1.6)Te_(3)界面裂纹明显改善,这是由于随Ni箔退火温度升高,Ni与Bi_(0.4)Sb_(1.6)Te_(3)之间的晶格失配得到改善,从而使Ni层与Bi_(0.4)Sb_(1.6)Te_(3)的连接性能提高。

The barrier layer between the Bi_(0.4)Sb_(1.6)Te_(3)thermoelectric material and the metal electrode is the controlling factor for the stable service of the thermoelectric device.In this paper,the spark plasma sintering diffusion welding method was used to prepare a Ni layer on the Bi_(0.4)Sb_(1.6)Te_(3)surface as a barrier layer for the Ni/Bi_(0.4)Sb_(1.6)Te_(3)electrode joint,in which high-density Ni foil and Bi_(0.4)Sb_(1.6)Te_(3)alloy were used as the raw materials.The phase analysis of the barrier layer was performed using X-ray diffractometer.The interface morphology and element distribution of the electrode joints were analyzed by the scanning electron microscope and its energy spectrometer.The results show that the Ni foil annealed at 700℃has excellent anti-diffusion effect,and the diffusion thickness is as low as 9μm.The Ni foil annealed at 700℃ is combined with Bi_(0.4)Sb_(1.6)Te_(3)by diffusion welding to obtain a bonding strength of 13.19 MPa.As the annealing temperature of Ni foil increases,Ni/Bi_(0.4)Sb_(1.6)Te_(3)interface cracks are significantly improved.This is because the lattice mismatch between Ni/Bi_(0.4)Sb_(1.6)Te_(3)can be improved with the incresing annealing temperature of Ni foil,thereby the connection performance of the Ni layer and Bi_(0.4)Sb_(1.6)Te_(3)is improved.