A Study of Thermodynamic Properties of Dilute Fe-Au Alloys by the 57Fe Mössbauer Spectroscopy
R. Konieczny, R. Idczak and J. Chojcan
Institute of Experimental Physics, University of Wrocław, Pl. M. Borna 9, 50-204 Wrocław, Poland
Received: August 10, 2016; In final form: December 19, 2016
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The room temperature Mössbauer spectra of 57Fe were measured for Fe1-xAux with the gold concentration ranging from 1 at.% till 4.8 at.%. They were analysed in terms of hyperfine parameters of their components related to unlike surroundings of the iron probes, determined by different numbers of gold atoms existing in the neighbourhood of iron atoms. Basing on the intensities of the spectrum components we determined binding energy Eb between two gold atoms in the studied materials. The latter was done for properly annealed samples using the extended Hrynkiewicz-Królas idea. It was found that the binding energy is positive or Au atoms interact repulsively. The extrapolated value of Eb for x =0 was used for computation of an enthalpy of solution of Au in Fe. Finally the obtained value of the enthalpy was used to predict the mixing enthalpy for the Fe-Au solid solutions. The results were compared with both the corresponding values resulting from the cellular atomic model of alloys by Miedema and those derived from experimental calorimetric data given in the literature.

DOI: 10.12693/APhysPolA.131.255
PACS numbers/topics: Mössbauer spectroscopy, hyperfine parameters, binding energy, short-range order, enthalpy of solution, enthalpy of mixing, binary alloys