Journalartikel

Jahr der Veröffentlichung: 2019

Seiten: 40769-40780

Zeitschrift: ACS Applied Materials & Interfaces

Bandnummer: 11

Heftnummer: 43

ISSN: 1944-8244

eISSN: 1944-8252

Open Access Status: Green

DOI Link: https://doi.org/10.1021/acsami.9b12474

Verlag: American Chemical Society

Abstract: 
Magnesium silicides can be used for thermoelectric energy conversion as high values of figure of merit zT were obtained for n-type (1.4 at 500 degrees C) and p-type (0.55 at 350 degrees C) materials. This, however, needs to be complemented by low resistive and stable contacting to ensure long-term thermogenerator operation and minimize losses. In this study, we selected Cu and Ni45Cu55 as contacting electrodes for their high electrical conductivity, similar coefficient of thermal expansion (CTE), and good adhesion to Mg-2(Si,Sn). Both electrodes were joined to Mg2Si0.3Sn0.7 pellets by hot pressing in a current-assisted press. Microstructural changes near the interface were analyzed using SEM/EDX analysis, and the specific electrical contact resistance r(c) was estimated using a traveling potential probe combined with local Seebeck scanning. Good contacting was observed with both electrode materials. Results show low r(c) with Cu, suitable for applications, for both n- and p-type silicides (<10 mu Omega.cm(2)), with the occurrence of wide, highly conductive diffusion regions. Ni45Cu55 joining also showed relatively low r(c) values (similar to 30 mu Omega.cm(2)) for n- and p-type but had a less inhomogeneous reaction layer. We also performed annealing experiments with Cu-joined samples at 450 degrees C for 1 week to investigate the evolution of the contact regions under working temperatures. r(c) values increased (up to similar to 100 mu Omega.cm(2)) for annealed n-type samples but remained low (<10 mu Omega.cm(2)) for p-type. Therefore, Cu is a good contacting solution for p-type Mg-2(Si,Sn) and a potential one for n-type if the diffusion causing contact property degradation can be prevented.

Harvard-Zitierstil: Ayachi, S., Hernandez, G., Pham, N., Farahi, N., Mueller, E. and de Boor, J. (2019) Developing Contacting Solutions for Mg₂Si_1-xSn_x-Based Thermoelectric Generators: Cu and Ni₄₅Cu₅₅ as Potential Contacting Electrodes, ACS Applied Materials & Interfaces, 11(43), pp. 40769-40780. https://doi.org/10.1021/acsami.9b12474

APA-Zitierstil: Ayachi, S., Hernandez, G., Pham, N., Farahi, N., Mueller, E., & de Boor, J. (2019). Developing Contacting Solutions for Mg₂Si_1-xSn_x-Based Thermoelectric Generators: Cu and Ni₄₅Cu₅₅ as Potential Contacting Electrodes. ACS Applied Materials & Interfaces. 11(43), 40769-40780. https://doi.org/10.1021/acsami.9b12474