Temperature dependence of the coercive field of gas atomized Fe73.5Si13.5B9Nb3Cu1

In this work, the dependence of the coercive field of Fe73.5Si13.5B9Nb3Cu1 gas atomized powder with the temperature for different particle sizes has been studied, observing an anomalous behavior in the under 25 powder particle size fraction. This unusual behavior is related with the microstructure of the powder, and is attributed to the presence of a multiphase magnetic system, with non-magnetic regions decoupling the ferromagnetic domains.

► An anomalous thermal dependence of the coercive field of gas atomized Fe73.5Si13.5B9Nb3Cu1 powder particles under 25 μm powder particle, increasing Hc as temperature increases.
► It is proposed that Cu rich regions at inter-grain boundaries could act as exchange decoupling regions contributing to the thermal increase of coercivity.
► This anomalous thermal dependence points out that tailoring microstructure and size, by controlling the cooling rate of more adequate multiphase systems, could be a promising procedure to develop soft or hard magnets, avoiding Rare Earths metals that is nowadays an important target for the engineering of magnetic materials.