Microstructure and magnetic properties of hard magnetic Pr

In the present work the phase constitution, microstructure and magnetic properties of the Pr9Fe52Co13Zr1Ti3B22 alloy ribbons in the as-cast state and subjected to short time annealing were investigated. The ribbons were obtained by melt-spinning technique (with the velocity of the copper roll surface of 15 m/s). Subsequently, the samples were annealed for 5 min at temperatures ranging from 923 to 1013K. The ribbon samples in as-cast state were fully amorphous and exhibited soft magnetic properties. Annealing at 923K resulted in partial devitrification of samples that has not changed considerably their magnetic properties. Heat treatment of specimens at higher temperatures caused the increase of volume fractions of hard magnetic phase, which was accompanied by significant changes of their hysteresis loops. The evolution of microstructure was studied by transmission electron microscopy TEM. Magnetic interactions between the grains of crystalline phases of selected samples were investigated basing on the deltaM plots determined from recoil curves