Effect of heat treatment process on the structural and soft magnetic properties of Fe38Co38Mo8B15Cu ribbons

In this study, the effect of crystal formation, grain growth and surface properties on magnetic properties via changed with heat treatment process in amorphous Hitperm-type alloy produced by planar flow casting method was investigated. The produced Fe38Co38Mo8B15Cu1 amorphous ribbons were subjected to selected heat treatments. The low temperature and short time heat-treated samples displayed broad, continuous, and low-intensity XRD diffraction peaks and the intensities of the crystalline peaks increased noticeably with increasing time and temperature. The AFM images of as-quenched Fe38Co38Mo8B15Cu1 ribbon surfaces displayed one type of sharp peak raises evenly distributed on the surfaces. The microstructural of the heat-treated samples exhibited nanocrystalline bcc-FeCo grains randomly dispersed in the remaining amorphous matrix. The mean sizes of grains increased from 1.8 nm to 5.6 nm with increasing heat-treatment temperature and time. The saturation magnetization increased from 81 to 135 emu/g with increasing heat-treatment temperature ranging from 300 to 420 degrees C and then decreased to 113 emu/g for 450 degrees C. The coercivity showed the or non-monotonous dependence with increasing annealing time and temperature.