Microstructure and magnetic properties of sintered NdFeB magnets with improved impact toughness

Abstract

An effort to increase the impact toughness of Nd–Fe–B sintered magnets by adding small amounts of Al, Nd, Ga, Cu, and Nb was successful. No significant compromise to magnetic properties occurred. Based on this work, a series of sintered Nd–Fe–B magnets with improved toughness was developed, which we call ToughNEO™. Small precipitates, which may contribute to the improvement of toughness, were observed using scanning electron microscope for all samples with improved toughness. Tumbling and drilling tests further verified the improved toughness of these developed ToughNEO™ magnets.

The mechanism of enhanced magnetic properties of sintered permanent magnets by substitution of Pr for Nd

“…The average particle size decreases from 2.77 m to 2.33 m as the Pr addition content increases from 0 to 100 wt%. This is because the toughness of the strip casting ribbons becomes lower with the decreases of Nd content [11,12]. In the jet milling process, the ribbons with higher Pr content are easily crushed into fine particle size powder, which means that fine JM powders could be obtained by increasing the Pr content in the alloys.…”

Effect of Pr and Dy substitution on the impact resistance of sintered Nd–Fe–B magnets

“…The impact resistance is one of the key factors that influence the reliability of brittle materials during commercial use. Liu et al and Liu et al reported [7,8] that impact toughness of sintered Nde FeeB magnets can be significantly improved by increasing the contents of Nd and doping elements such as Nb, Cu, Al, etc. The change of the mechanical properties after rare-earth element substitution such as Pr and Dy in sintered NdeFeeB magnets has never been studied.…”

Improved magnetic properties and fracture strength of NdFeB by dehydrogenation

“…Moreover, some applications of magnets for structural elements that require magnets to operate under mechanical stresses have been limited due to the insufficient strength of currently available magnets. Further improvement in strength and toughness of magnets will widen the fields of application [7,8]. In this paper, effects of the hydrogen desorption process on magnetic properties and fracture strength of sintered NdFeB were investigated.…”