Jan Chojcan

Interactions between impurity atoms of 3d transition metals dissolved in iron

Abstract We present results of our Mossbauer spectroscopy study on the distribution of impurity atoms in iron based solid solutions of iron with Ti, V, Mn, Co and Ni as a solute. The results are analysed in the terms of interaction energies of impurity pairs in iron. The energies obtained for the Ti, V and Mn pairs are positive (repulsive interaction) whereas for Co and Ni pairs they are negative (attractive interaction). The data are compared with those resulting from the Miedema–Krolas model for the energy. From the comparison it follows that our experimental values are in agreement with the model for Ti and V pairs but that they are in disagreement with the model predictions for Mn, Ni and Co pairs.

A Dilute-Limit Heat of Solution of 3d Transition Metals in Iron Studied with 57Fe Mössbauer Spectroscopy

The room-temperature 57Fe Mossbauer spectra for binary iron-based solid solutions Fe1−x D x with D = V, Cr, Mn and Co, were analysed in terms of binding energy E b between two D atoms in the Fe-D system. The extrapolated values of E b for x = 0 were used for computation of the dilute-limit heat of solution of D metals in iron. The results were compared with those derived from calorimetric data concerning the heat of formation of the systems mentioned as well as with those resulting from the Miedema’s model of alloys. The comparison shows that our Mossbauer spectroscopy findings are in a qualitative agreement with the available calorimetric data and they are at variance with corresponding Miedema’s values for Fe-Mn and Fe-Co systems.

Interactions between V atoms in iron-based Fe–V solid solutions

Abstract The room temperature 57 Fe Mossbauer spectra were measured for iron-based solid solutions Fe 1− x V x with x in the range 0.03≤ x ≤0.10. The obtained data were analyzed in terms of the binding energy E b between two V atoms in the Fe–V system using the extended Hrynkiewicz-Krolas idea. It turned out that the energy decreases with x from about 40 meV for x =0.03 to zero for x >0.08 and its extrapolated value for x =0 is close to 140 meV. It seems that the findings can be useful for verification of the corresponding calorimetric data since the data published by different authors are essentially distinct. The E b value in the dilute limit ( x =0) estimated on the basis of the dilute-limit heat of solution of V atoms in Fe matrix derived from the data by Myles and Aldred [J. Phys. Chem. 68 (1964) 64] amounts to 201 meV, whereas the corresponding binding energy resulting from the data by Kubaschewski et al. [Z. Phys. Chem. 104 (1977) 23] is 78 meV.

Interactions between osmium atoms dissolved in iron observed by the 57Fe Mössbauer spectroscopy

Abstract The room temperature 57Fe Mössbauer spectra for binary iron-based solid solutions Fe1−xOsx, with x in the range 0.01 ≤ x ≤ 0.05, were analyzed in terms of binding energy Eb between two Os atoms in the Fe-Os system. The extrapolated values of Eb for x = 0 were used for computation of enthalpy of solution of osmium in iron. The result was compared with that resulting from the cellular atomic model of alloys by Miedema. The comparison shows that our findings are in qualitative agreement with the Miedemas model predictions.

Thermal defects in Fe–Cr solid solutions revealed by 57Fe Mössbauer spectroscopy

Abstract On the basis of room temperature 57 Fe Mossbauer spectra for iron-based Fe–Cr solid solutions quenched from different temperatures, it is suggested that the 57 Fe Mossbauer spectroscopy can be successfully applied to the study of the thermally generated defects in the Fe–Cr systems. Using the technique one can investigate both Schottky vacancies as well as a possible thermal distortion of the lattice.

Hyperfine fields at 57Fe in dilute iron-based alloys determined by Mössbauer spectroscopy

The room temperature Mossbauer spectra of 57Fe were measured for several dilute iron-based alloys, Fe1−xDx (D = Co, Cr, Mn, Mo, Pt, Re, Ta, V, W), annealed at 1270 K for 2 h before the measurements. The analysis of the spectra shows that the effective hyperfine field B at 57Fe nuclei depends on the concentration x of the minority component of the alloys under consideration and the dependence is different for iron nuclei having unlike numbers of impurities in their neighbourhood. The latter is at variance with previously published data, which suggest that the general B(x) dependence is common for all impurity configurations present in the vicinity of iron nuclei.

Mean hyperfine fields at 57Fe in dilute iron-based alloys studied by Mössbauer spectroscopy

Abstract The room temperature Mössbauer spectra of 57Fe were measured for numerous dilute iron-based alloys Fe1−xDx (D = Al, Co, Cr, Mn, Mo, Ni, Os, Pt, Re, Ru, Ta, Ti, V, W, Zn), annealed at 1270 K for 2 h before the measurements. The spectra were analyzed using the Hesse–Rübartsch method in order to determine the mean hyperfine magnetic field at the 57Fe nuclei as a function of concentration x of the minority component of the alloy. As the binary alloys are one-faze solid solutions of an element D in iron, a linear relationship between and x is observed. The result supports the suggestion that Mössbauer spectroscopy is a useful tool for the study of dissolution of different elements in iron.