On the Homogeneity of Single Phase Obtained in Metallic Systems with Positive Heat of Mixing

Abstract

X-ray diffraction and absorption spectroscopy measurements have been performed in metastable solid materials obtained by mechanical attrition or codeposition process of immiscible systems in view to investigate the short and long range order obtained inside these solutions. Firstly, experiments show that CuBoFeloColo milled powders are in quasi perfect solid solution ; this result arouses interest because giant magnetoresistance is more readily controlled by decomposition of a supersatured solid solution. Secondly, codeposition of CuSOMoSO presents a long range order typical of a well-defined cristalline structure whereas the short range order appears very disordered.

Structural coherence between phases in Ni0.35Ag0.65thin films

“…Frequently, the lattice parameter of each phase, determined from this long-range-order investigation, is plotted versus the mean composition of the sample: a continuous evolution of such a parameter (a Vegard law dependence) is attributed to the presence of a solid solution in the material analysed. Nevertheless, no information about the homogeneity of this solid solution can be obtained from this simple analysis, and a short-range study of the neighbourhood of each element in this phase has to be performed, by x-ray absorption spectroscopy (XAS) for example [17]. The lack of the series of reflections associated with interplanar distances of the pure element does not prove the existence of an alloy phase: experimental evidence that such an interpretation may be erroneous has already been obtained for two binary systems, Cu-Co [18] and Au-Pt [19].…”