The influence of Cu and Nb on the crystallization products of annealed FeCuNbSiB

Depending on different Nb and Cu concentration, we studied the formation of nano- and microcrystalline phases in differently annealed samples of FeCuNbSiB. First, the kinetics of crystallization was explored by measuring the temperature-dependent electrical resistivity and magnetization. After this, we collected Mössbauer spectra and did an X-ray diffraction analysis of annealed samples at chosen temperatures to discover the different crystalline phases. It was found how the onset of crystallization had been shifted towards other temperatures. The analysis of Mössbauer spectra shows that building up the well-known DO₃ structure of Fe₃Si is disturbed in the alloy without Cu. At higher Nb content, we resolve two different crystallization steps in the formation of Fe₃Si and a new crystalline phase, probably being a structure like Fe₂₃B₆.