Journal of Materials Science

, Volume 50, Issue 7, pp 2700–2708

Bonding and high-temperature reliability of NiFeMo alloy/n-type PbTe joints for thermoelectric module applications

  • Haiyang Xia
  • Fivos Drymiotis
  • Cheng-Lung Chen
  • Aiping Wu
  • Yang-Yuan Chen
  • G. Jeffrey Snyder
Original Paper

DOI: 10.1007/s10853-015-8820-8

Cite this article as:
Xia, H., Drymiotis, F., Chen, CL. et al. J Mater Sci (2015) 50: 2700. doi:10.1007/s10853-015-8820-8

Abstract

PbTe is an extremely important thermoelectric (TE) material, due to its high TE conversion efficiency. Consequently, our effort focuses on developing PbTe-based TE modules, which requires developing novel approaches for bonding metallic contacts to PbTe. In this study, Fe, Mo, and NiFeMo alloy foils were directly bonded to n-type PbTe using a rapid hot press at 600, 700, or 800 °C under a pressure of 40 MPa and for various holding times. We find that in the case of Fe and Mo, it is difficult to form a metallurgically bonded high strength joint with PbTe. However, we find that NiFeMo alloy does effectively bond to PbTe at 700 °C, but not at 600 °C. Significant liquid Pb, which might be due to the reaction of PbTe with Ni, is found that penetrates along the NiFeMo grain boundaries near NiFeMo/PbTe joints during bonding at 700 °C where the extent of liquid Pb penetration can be controlled with the time of bonding. Furthermore, the Seebeck coefficient of bulk PbTe with NiFeMo contacts is similar to that without NiFeMo contacts. Finally, the accelerated thermal aging of NiFeMo/PbTe elements at 600 °C for 240 h shows that the failure mechanism of NiFeMo/PbTe joints under operating conditions is the continued formation and penetration of eutectic liquid NiFeMo–PbTe and liquid Pb along the NiFeMo grain boundaries.

Copyright information

© Springer Science+Business Media New York 2015

Authors and Affiliations

  • Haiyang Xia
    • 1
    • 2
    • 3
  • Fivos Drymiotis
    • 1
  • Cheng-Lung Chen
    • 1
    • 4
  • Aiping Wu
    • 2
    • 3
  • Yang-Yuan Chen
    • 4
  • G. Jeffrey Snyder
    • 1
  1. 1.Department of Materials ScienceCalifornia Institute of TechnologyPasadenaUSA
  2. 2.Department of Mechanical EngineeringTsinghua UniversityBeijingChina
  3. 3.Key Laboratory for Advanced Materials Processing TechnologyMinistry of EducationBeijingChina
  4. 4.Institute of PhysicsAcademia SinicaTaipeiTaiwan