Nano/sub-micron crystallization of Fe-Co-7.15V alloy by thermo-mechanical process to improve magnetic properties

In this study, the effect of nano/sub-micron crystallization on the magnetic properties of Fe-Co-7.15V alloy was investigated. Hence, cold-rolled Fe-Co-7.15V alloy (with 90% reduction) was annealed in different conditions. The magnetic properties of the annealed samples were measured by vibrating sample magnetometer. It was found that the best magnetic properties of the cold-rolled alloy were obtained after annealing at 550 °C for 2 h. The performed microstructural studies by field emission scanning electron microscope, showed that improvement of coercivity by annealing was related to the partial recrystallization and the formation of nano/sub-micron grains. Also, the magnetic studies showed that saturation induction was reduced by annealing at temperatures higher than 450 °C. The performed phase identification by X-ray diffraction analysis indicated that a decrease in saturation induction was related to the formation of residual non-magnetic γ phase.