A Study of Thermodynamic Properties of Dilute Fe-Au Alloys by the ⁵⁷Fe Mössbauer Spectroscopy

Abstract

The room temperature Mössbauer spectra of 57 Fe 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 E b 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 E b 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.

Recovery of Gold and Iron from Cyanide Tailings with a Combined Direct Reduction Roasting and Leaching Process

“…Atomic Au and Fe can form Au-Fe alloys at high temperature [23]. The unique electrical [24], magnetic [25], thermodynamic [26] and catalytic [27] properties of Au-Fe alloys have attracted great interest. It suggests that gold remains in cyanide tailings can be captured and enriched in metallic iron if a high-temperature reduction process is conducted.…”

Perpendicular magnetic anisotropy at Fe/Au(111) interface studied by Mössbauer, x-ray absorption, and photoemission spectroscopies

“…As the two components have almost equal intensities, the 57 Fe layer faces the interface with Fe-Fe and Fe-Au chemical bonds. The enhancement of H hf at the interfacial component is explained by Fe-Au bonding because the Au solute in the Fe 1−x Au x alloy influences to increase H hf [41]. The difference in H hf of 3 T corresponds to 0.17 meV energy.…”