Primary crystallization and hard magnetic properties of Nd60Al10Fe20Co10 metallic glasses

Abstract

The primary crystallization in Nd60Al10Fe20Co10 ribbons and its effect on magnetic properties are investigated by means of DSC, x-ray diffraction, vibrating sample magnetometer and high-resolution electron microscope (HREM). The kinetic primary crystallization is found in the DSC traces of Nd60Al10Fe20Co10 ribbons and is invisible in annealed ribbons and as-cast rods. The amorphous feature of the as-spun ribbons is determined by HREM and is in accordance with the reduced glass transition temperature (about 0.52) of the alloy. Ribbons annealed at 473 K contain the same nano-scaled particles as those in as-cast rods and exhibit a coercivity higher than as-spun ribbons but much lower than as-cast rod. The enhanced coercivity of the ribbons depends strongly upon the primary crystallization, and the difference in coercivity between as-cast rods and annealed ribbons is attributed to the different volume fraction of the nano-scaled particles in the samples.