Thermodynamic properties of nonstoichiometric intermetallic compounds Fe3Al with DO3 structure

Yong Zhang Huang, Wen Xia Yuan, Hong Min Zhu, Zhi Yu Qiao

Research output: Contribution to journalArticlepeer-review

Abstract

The electromotive force(EMF) values of the cell (-) Pt | Ir | Al 0.85 Sn0.15, Na3AlF61 | CaF 2 | AlxFe1-x, (x=0.23-0.33), Na 3AlF6 | Ir | Pt (+) were measured between 720 K and 847 K using solid galvanic cells with a single-crystal CaF2 electrolyte. For attaining quick thermodynamic equilibrium of the cell, Al 0.85Sn0.15 alloy was used as the reference electrode and DO3-Fe3Al was powdered. It was confirmed that there was no chemical transformation in the working electrode by X-ray diffraction experiments before and after EMF measurement. The Al activities in Fe 3Al with DO3-ordered nonstoichiometric intermetallic compounds were derived. The partial molar thermodynamic functions ΔḠAAl, ΔH̄Al, ΔS̄ Al of Al were calculated. The activities and partial molar Gibbs energies of Fe in the Fe-Al alloys were derived by Gibbs-Duhem equation. The thermodynamic factor in diffusion of aluminum in the Fe3Al phase at 750 K was calculated, and showed a maximum at a composition near the stoichiometric proportion (xAl=0.25).

Original languageEnglish
Pages (from-to)273-277
Number of pages5
JournalActa Physico - Chimica Sinica
Volume21
Issue number3
Publication statusPublished - 2005 Mar 1
Externally publishedYes

Keywords

  • Activity
  • CaF
  • Electromotive force (EMF)
  • FeAl
  • Thermodynamic factor

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

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