Structure studies of Fe-based metallic glasses by Mössbauer spectroscopy method

Received 10.01.2011; published in revised form 01.03.2011 Purpose: The paper presents a structure characterization of selected Fe-based metallic glass in as-cast state. Design/methodology/approach: The studies were performed on Fe72B20Si4Nb4 metallic glass in form of ribbons. The amorphous structure of tested samples was examined by X-ray diffraction (XRD) and transmission electron microscopy (TEM) methods. Mössbauer spectroscopy method was applied to comparison of structure in studied amorphous samples with different thickness (cooling rates). Findings: The XRD, TEM and Mössbauer spectroscopy investigations revealed that the studied alloy in as-cast state was amorphous. Comparison of diffraction patterns of studied samples with different thickness showed the slightly narrowing of diffraction lines. The TEM observations also revealed a changing of image contrast of glassy ribbons with increase of sample thickness. The Mössbauer spectra presented broadened six line patterns characteristic to the structural disorder of amorphous ferromagnetic materials. The hyperfine magnetic field distributions for studied sample thickness indicated the existence components corresponding to the regions with different iron concentration (an iron-rich and an iron-poor surroundings). Practical implications: The Mössbauer spectroscopy is very useful method in studying the structural environment of Fe atoms on a nearest-neighbor length scale allowing the analysis of iron-containing phases. Originality/value: The obtained examination results confirm the utility of investigation methods in analysis of microstructure in function of sample thickness.