Low Temperature Joining and High Temperature Application of Segmented Half Heusler/Skutterudite Thermoelectric Joints.

Weian Wang,Yefeng Bao,Yunfei Xing,Xiaoya Li,Ming Gu

doi:10.3390/ma13010155

Abstract

A low temperature joining process has been developed to fabricate segmented half Heusler/skutterudite thermoelectric joints, and high temperature service behavior of the joints has been studied. The microstructure and electrical resistance across the joint before and after aging were investigated. The joint is well bonded and no cracks appear at the interfaces of the joint before and after aging, which can attribute to the formation of high melting point intermetallic compounds. The electrical resistance crosses the bonding layer smoothly and the contact resistance is low. These results show the process is effective, and promising for preparation of segmented thermoelectric devices.

Highlights

Thermoelectric (TE) materials that can convert heat into electricity directly have found important applications in radio-isotope thermoelectric generators used in space exploration [1], and become increasingly appealing for waste heat recovery in industries [2]
Ouyang [15] reported a calculated conversion efficiency up to 20.9% over a temperature range of 300 K to 1000 K for segmented devices made of state-of-the-art TE materials
In this paper we report a new process for low temperature joining of segmented thermoelectric materials, which succeeded in avoiding the bad effect on the TE

Summary

Introduction

Thermoelectric (TE) materials that can convert heat into electricity directly have found important applications in radio-isotope thermoelectric generators used in space exploration [1], and become increasingly appealing for waste heat recovery in industries [2]. It is necessary to use different TE materials in each temperature range to get high ZT and conversion efficiency over a wide temperature range. Ouyang [15] reported a calculated conversion efficiency up to 20.9% over a temperature range of 300 K to 1000 K for segmented devices made of state-of-the-art TE materials. Bulat [21] tried to solve this problem by developing temperature gradient sintering technique Brazing is another choice, but usually the brazing temperature is much higher than the service temperature of the low temperature segment. In this paper we report a new process for low temperature joining of segmented thermoelectric materials, which succeeded in avoiding the bad effect on the TE properties of the low temperature segments. Reported is the high temperature service behavior of the segmented TE joints

Materials and Methods

Results and Discussion

Conclusions