Magnetization processes of hard magnetic composites - Monte Carlo studies

In the present work we performed some simulated annealing plus Monte Carlo studies concerning a hard magnetic spherical particles embedded into soft ferromagnetic matrix as well as irregular branches of soft and hard magnetic phases. Magnetization process of such system depends on exchange interactions of soft and hard magnetic object and interface between them. Especially interesting is the comparison of interactions in systems with different, regular and irregular geometry[…

Size effect of hard magnetic properties of Fe-Nb-B-Tb milled alloys

The paper refers to magnetic and structural properties of powders made of Fe-Nb-B-Tb ultra-high coercive alloy. The initial alloy was milled in a low energy mill for 1 h and 14 h. With increasing milling time we observed gradual deterioration of hard magnetic properties i.e. the coercive field decreases from 5.51 T to 0.14 T for the bulk alloy and 14 h milled powder, respectively. However, for the 1 h milling time the micrometric powder reveals quite high coercivity of 2.77 T which is promising for possible applications in magnetic composites[…

Ultra-fast current aided sintering of high coercive magnetic powders and composites

The paper refers to pulverization and sintering of the (Fe80Nb6B14)0.88Tb0.12 high coercive alloy. The powder was sintered using the ultra-fast current aided method. It turned out that too long discharge time leads to appearing of a soft magnetic phase and simultaneously, decrease in coercivity of the compacted powder. Nevertheless, it was possible to establish preference technology parameters, preserving magnetic hardness of the alloy. As a final test, an impact of Co-powder addition on magnetic properties was studied. The introduced soft magnetic phase (about 20 wt. %) caused about 30% increase of magnetic remanence, which is a result of direct exchange interactions between the two phases