Effects of grain size on coercivity of combined-reaction-processed FePd intermetallics

Abstract The evolution of the microstructure and the coercivity of cold-deformed ferromagnetic Fe–Pd intermetallics with equiatomic composition during isothermal annealing at 500 and 600 °C has been studied by X-ray diffraction, scanning and transmission electron microscopy and vibrating sample magnetometry. The deformation-processed alloys exhibit morphologically essentially equiaxed microstructures and up to about fivefold increased coercivity compared with conventionally processed bulk L10-ordered FePd. An inverse linear relationship between the coercivity and the average grain size has been established, which for grain sizes in the range of about 0.4–1.0 μm has been attributed to a nucleation-type coercivity mechanism.