Electroless Fabrication of Nd-Fe-B/α-Fe Heterostructured Composite Magnets and their Magnetic Properties

Abstract:

Electroless plating was used to coat Fe layers on the hard magnetic Nd-Fe-B powders to fabricate Nd-Fe-B/α-Fe heterostructured magnetic powders. The heat treatment was performed to study the property evolution of the heterostructured magnetic powders. The results show that Fe coating was oxidized to Fe₂O₃ while drying; through the hydrogen reduction annealing, Fe₂O₃ was reduced to α-Fe. The coercivity of the heterostructured magnetic powders increased from 111.3 kA/m (1.4 kOe) to 524.7 kA/m (6.6 kOe) after annealing at 650°C. However, the demagnetization curve of powders presents a kink due to un-ideal coupling between hard and soft magnetic phases because of the aggregation of α-Fe. The magnetization processes of the heterostructured powders transferred from the dominant nucleation mechanism to domain wall pinning mechanism after the heat treatment.

• Periodical: Materials Science Forum (Volumes 809-810)
• Pages: 426-432
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.809-810.426
• Online since: December 2014
• Authors: Xiao Dong Fan, Na Tian, Cai Yin You*
• Keywords: Coercivity, Electroless Plating, Heterostructure Magnetic Powders, Hydrogen Reduction

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