Tripling magnetic energy product in magnetic hard/soft nanocomposite permanent magnets

Abstract

Nanocomposite materials comprising two or more nanoscale functional components attracted more attention due to their high performance than that of the corresponding single counterpart, which have wide potential applications in many fields. The manipulation of the component phases, fraction/distribution of each phase, and grain size in the nanocomposite is of priority to obtain a high performance. Here, in this work, a two-step process of optimal high-energy ball milling followed by optimal low temperature annealing had been adopted to fabricate Sm–Co/FeCo nanocomposite magnets with triple magnetic energy product in triple-phase nanocomposites. An evolution of microstructure including morphology, phase constitution and grain size towards a high performance magnet had been investigated, which resulted in a record high maximum energy product of 29.1 MGOe. The microstructure of well distributed nanoscale SmCo3 and SmCo5 duplex hard phases and soft phase with almost equal percent is the key factor to get this high performance. The fabrication procedure in controlling the microstructure with uniformly distributed triple phases and nanoscale grain size will shed light on synthesizing other types of nanocomposite materials with high performance.