Mössbauer spectroscopy characterization of Zr-Nb-Fe phases

C. P. RAMOS; M. GRANOVSKY; C. SARAGOVI

La Plata

Workshop; 35th Anniversary of Hyperfine Interactions at La Plata International Workshop and Humboldt Kolleg on Solid State Physics; 2005

The aim of this work was the characterization of the ternary phases and of those coming from the corresponding binary systems in the Zr-Nb-Fe diagram by means of Mössbauer Spectroscopy. This is part of a complete study involving a tentative isothermal section at 900°C of the center of the Zr-Nb-Fe diagram which will be published elsewhere. In this kind of works Mössbauer spectroscopy is not a commonly used technique, however our results and previous studies [1-3] demonstrates that it gives very useful information, sometimes not provided by other techniques. Zr-Nb-Fe alloys with Nb contents between 5 and 50 at.% and Fe contents between 10 at.% and 60 at.% were analyzed both, as cast and after a heat treatment at 900°C during 4 months. Mössbauer characterization of the phases was complemented by optical and scanning electron microscopies, X-ray diffraction and electron microprobe analysis. From the obtained results it can be inferred that Fe in both of the Laves phases present in this system (Zr(FeNb)2 and (ZrNb)Fe2) sees different environments producing quadrupole splitting and hyperfine field distributions respectevely. Two types of body centered cubic betha phases (Zr-rich and Nb-rich) were found having noticeable differences in their Mössbauer parameters. Furthermore it was shown that the ternary Fe(NbZr)2 compound would show magnetic character at low temperatures. Concentration dependence of the hyperfine parameters and their relations with the lattice parameters contributed to the structural characterization of the phases.     [1] C. Ramos, C. Saragovi, M. Granovsky, D. Arias. Hyp. Interact. 122 (1999) 201 [2] C. Ramos, C. Saragovi, M. Granovsky, D. Arias. Hyp. Interact. 139/140 (2002) 363 [3] C. Ramos, C. Saragovi, M. Granovsky, D. Arias. J. Nuc. Mat. 312 (2003) 266