INFLUENCE OF ANNEALING TEMPERATURE ON MAGNETIC MICROSTRUCTURE OF Fe76Mo8Cu1B15 ALLOY

Magnetic microstructure of NANOPERM-type Fe76Mo8Cu1B15 alloy is studied by 57 Fe Mossbauer spectroscopy in amorphous and nanocrystalline states. The method used provides detailed a view on structural and magnetic changes induced by heat treatment. The latter was performed in the range from 300 to 550 ◦ C for 1 hour. Mossbauer spectra recorded at room temperature and at the temperature of liquid nitrogen were analyzed by the help of distributions of hyperfine fields and quadrupole splitting. The crystalline phase that evolved after annealing at 450 ◦ C represents iron atoms in bcc arrangement. With increasing the temperature of heat treatment above the first crystallisation stage, different amounts of nanocrystallites were obtained reaching up to 40% of the total volume fraction. K e y w o r d s: Mossbauer spectroscopy, nanocrystalline alloys, hyperfine fields