Effect of doping Al-Cu-Fe alloy on the microstructure and magnetic properties of annealed Nd-Fe-Co-B ribbons

• Published in: Physica. B, Condensed matter Condensed matter, 2022-12, Vol.646, p.414333, Article 414333
• Main Authors: Wang, Shu, Sun, Ji-Bing, Xiao, Zhi-Xia, Yang, Ming-Xu, Shi, Wei-Dong
• Format: Article
• Language: English
• Subjects: Annealing; Magnetic properties; Microstructure; Permanent magnetic magnets; Phase transition
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2022.414333

Doping 1 wt% Al89.5Cu9.7Fe0.8 alloy promotes the phase separation of Nd13.53Fe74.89Co5.54B6.04 alloy, forming the unique microstructure of small Nd-rich particles embedded in the large equiaxed Al-Cu-Fe-rich grains with the same Nd2Fe14B-type structure. Low-temperature annealing at 650 °C–710 °C improves the disorder degree of Nd2Fe14B-type phases and reduces the composition difference between different phases. Correspondingly, the large amorphous regions reduce to ∼20 nm small particles, and the small amorphous regions are crystallized into nanoclusters or nanoparticles. When the annealing temperature exceeds 750 °C, the grain composition is thoroughly homogenized, and the grains begin to overgrow. Al-Cu-Fe addition improves the thermal stability of some Fe-rich amorphous particles and makes them difficult to crystallize. Compared to the as-spun ribbons, annealing at 710 °C increased the coercivity by 72%, the remanence by 34%, and the maximum magnetization by 2.0%. At the same time, the corresponding microstructure evolution models are established. •Annealing changed the microstructure of Nd-Fe-Co-B ribbons.•The Hc, Mr, and M2T increased by 72%, 34%, and 2.0%, respectively.•The addition of Al-Cu-Fe alloy promotes phase separation and solute separation.•The microstructure consists of two types of Nd2Fe14B-type grains.•Proposed the new microstructure evolution models.