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).
|Number of pages||5|
|Journal||Acta Physico - Chimica Sinica|
|Publication status||Published - 2005 Mar 1|
- Electromotive force (EMF)
- Thermodynamic factor
ASJC Scopus subject areas
- Physical and Theoretical Chemistry