Detrimental effect of powder processing on the thermoelectric properties of CoSi

Hui Sun, Xu Lu, Donald T. Morelli

Research output: Contribution to journalArticle

Abstract

Cobalt monosilicide (CoSi) prepared by arc melting possesses a very high thermoelectric power factor of 60 μW cm−1 K−2 at room temperature. The high lattice thermal conductivity of CoSi, however, limits its thermoelectric efficiency. In this paper, powder processing technique was intentionally used to reduce the grain sizes of CoSi and thus suppress its lattice thermal conductivity. The effects on the thermoelectric properties of CoSi under various processing conditions were explored. The electrical resistivity is drastically increased, while the absolute Seebeck coefficient is decreased for the powder processed samples compared to the arc-melted one. The detrimental influence is attributed to the grain boundary defects produced during processing, which brings about an excessive energy filtering effect and hence induces a huge decrease in the absolute Seebeck coefficient. The lattice thermal conductivity of powder processed samples is reduced as expected. However, the reduction is always offset by the reduction in the mobility due to the similar mean free paths of electrons and phonons of CoSi. As a result, it may not be feasible to upgrade the thermoelectric performance of the CoSi system by powder processing.

LanguageEnglish (US)
Pages1-7
Number of pages7
JournalJournal of Materials Science
DOIs
StateAccepted/In press - Mar 29 2017

Profile

Powders
Thermal conductivity
Seebeck coefficient
Processing
Thermoelectric power
Phonons
Cobalt
Grain boundaries
Melting
Defects
Electrons
Temperature

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Detrimental effect of powder processing on the thermoelectric properties of CoSi. / Sun, Hui; Lu, Xu; Morelli, Donald T.

In: Journal of Materials Science, 29.03.2017, p. 1-7.

Research output: Contribution to journalArticle

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