Interfacial reactions in Zn4Sb3/titanium diffusion couples

Cheap, environmentally-friendly zinc antimonide is considered more favorable than conventional telluritebased and skutterudite thermoelectric (TE) materials. Although the highly mobile zinc atoms located in the interstitial sites of the Zn4Sb3 crystalline structure greatly increase the figure of merit (ZT) of TE materials, the high chemical activity of zinc also makes it difficult to find suitable barrier layer and electrode materials. This paper introduces a method of joining titanium with Zn4Sb3 by means of diffusion bonding, in which the critical mutual-interdiffusion phenomenon is prevented. Optimal process parameters for manufacturing TE modules are suggested in this work. The intermetallic compounds (IMCs) that formed at the interface of Zn4Sb3/Ti diffusion couples were proved to be stable at the temperature with the highest conversion efficiency of Zn4Sb3. The growth kinetics of IMCs were also investigated, and the joint strength could be enhanced to 13.9 MPa after long-term reliability tests of 1000 h without deterioration. The results indicated that titanium is feasible barrier layer and electrode material for Zn4Sb3 TE modules. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study introduces a method of joining titanium with zinc antimonide by diffusion bonding, preventing critical mutual-interdiffusion phenomenon, and suggests optimal process parameters for manufacturing TE modules. It is proved that titanium can serve as suitable barrier layer and electrode material for Zn4Sb3 TE modules.