Fabrication and Evaluation of CoSb3/Electrode Thermoelectric Joints

Joining of TE material to electrode is the key technique in the construction of TE device for the practical applications. In this study, a suitable alloy electrode was introduced into CoSb3-based element by means of spark plasma sintering (SPS). Finite element analysis showed that the maximum thermal residual stress appeared at the cylindrical surface zone close to the CoSb3/electrode interface. Microstructure of CoSb3/electrode was investigated by EPMA and the intermetallic compound (IMC) layers were found. The shear strength of CoSb3/electrode joints was tested and the results show that the joints have sufficient strength for reliability of TE device. Electrical contact resistance between CoSb3 and electrode was measured by means of four-probe technique. The results show that the contact resistance was minimal and below the 50μΩ.cm2, which meant the joint exhibited a good electrical contact. The high temperature reliability evaluation showed good thermal duration stability of the CoSb3/electrode joints.