Mechanical alloying and spark plasma sintering of higher manganese silicides for thermoelectric applications

Yatir Sadia, Liron Dinnerman, Yaniv Gelbstein

Research output: Contribution to journalArticlepeer-review

61 Scopus citations

Abstract

The present challenges in the energy crisis require finding new ways to reduce consumption of fossil fuels. Thermoelectrics can help reduce fuel consumption by producing electricity from waste heat. The higher manganese silicides (HMS) have shown promise in this field as inexpensive, nontoxic and highly stable p-type thermoelectric materials. One of the production techniques for HMS is mechanical alloying by ball milling. In this research the effect of the ball-milling duration and speed on the phases produced was studied. Mn and Si powders were milled at speeds of 200 RPM to 800 RPM for 1 h to 7 h. X-ray diffraction (XRD) results of the samples prepared using mechanical alloying show deterioration into the MnSi phase. The sample that underwent 5 h of milling at 800 RPM showed the greatest amount of HMS phase and was subsequently spark plasma sintered. The sample showed insufficient thermoelectric properties (ZT ≈ 0.1 at 450 C), compared with either solid-state reaction samples showing ZT ≈ 0.4 or cast samples showing ZT ≈ 0.63 at 450 C. The reduced ZT values of the mechanically alloyed and spark-plasma-sintered samples were attributed to the high relative amount of MnSi phase. The correlation between the relative amount of MnSi and the transport properties is described in detail.

Original languageEnglish
Pages (from-to)1926-1931
Number of pages6
JournalJournal of Electronic Materials
Volume42
Issue number7
DOIs
StatePublished - 1 Jul 2013

Keywords

  • Higher manganese silicides
  • mechanical alloying
  • spark plasma sintering
  • thermoelectric

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry

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