Nanocrystalline materials, which have been proposed to represent a new solid state structure, are investigated by Mössbauer spectroscopy. Nanocrystalline materials are polycrystals with a crystal size of typically 1–10 nm. These materials consist of two components of comparable volume fractions: a crystalline component and an interfacial component, formed by the atoms located either in the crystals or in the interfacial regions between them. As the atomic configurations of both components are different, two kinds of Mössbauer spectra are expected. Iron nanocrystalline material is found to exhibit a two-component Mössbauer spectrum, consisting of a crystalline component and a second one with different Mössbauer parameters. The Mössbauer parameters of the second subspectrum are consistent with the model of the interfacial component of a nanocrystalline material.

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Fe-B alloys in both a nanostructural state and a disordered amorphous-like state have been produced using a novel ball-mill method. Mossbauer measurements at room temperature and 4.2 K on materials of nominal starting compositions Fe80B20 to Fe40B60 combined with X-ray diffraction and differential scanning calorimetry, revealed that samples with low B-content (or approximately=50 at.% B) formed primarily in an amorphous-like state. The detectable B content of the mechanically alloyed samples was found to be lower than the nominal composition for all samples. The presence of unreacted B was confirmed by annealing experiments in which the expected fractions of phases alpha -Fe, Fe2B and FeB were obtained as crystallization products. In the samples, which partially exhibit a nanostructural state, B seems to be present only in the disordered interfacial regions.

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