Annealing Time Dependence on the Phase Equilibria and Thermoelectric Property of Type-I Ba₈Cu₆Ag₂Si₃₈ Clathrate

Abstract:

Poly-crystalline Ba₈Cu₆Ag₂Si₃₈ clathrates were synthesized by the arc-melting method and a subsequent annealing treatment. The main phase of all the samples was type-I clathrate. However, there were some precipitates which rich in Cu, Ag or Si in the grain boundary of the as-synthesized sample and the precipitates gradually reduced with the increase of annealing time. The transition metal content in the clathrate increased with the annealing time because of the diffusion of the Cu and Ag atoms from precipitates phase into clathrates phase. The as-synthesized sample was n-type material. For the 576 hours annealed sample, the carrier type changed from n-type to p-type because of the increase of Cu and Ag content in the clathrate.

• Periodical: Applied Mechanics and Materials (Volume 310)
• Pages: 59-62
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.310.59
• Online since: February 2013
• Authors: Bin Liu, Makoto Saisho, Yuya Nagatomo, Takuya Oka, Toshiko Osada, Hideshi Miura, Osamu Furukimi, Shinji Munetoh
• Keywords: Ag Substitution, Annealing, Clathrate, Cu Substitution, p-Type Materials, Seebeck Coefficient, Silicon

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