Coercivity study of hybrid magnet consisting of R-lean and R-rich phases

Coercivity of the hybrid magnets prepared by a hot pressing and subsequent die-upsetting the blends of R-rich (Nd_13.5Fe₈₀Ga_0.5B₆) and R-lean [Nd_xFe_93-xNb₁B₆ (x=6 and 9)] melt-spun ribbons was investigated. The effects of the amount and composition of the added R-lean alloy on the coercivity of the hybrid magnets were examined. The effect of deformation during the die-upsetting on the coercivity was also investigated. The magnetically significantly dissimilar R-rich Nd₂Fe₁₄B single phase region and R-lean nanocomposite region in the hybrid die-upset magnet were well coupled via a magnetostatic interaction. The coercivity of the compacted and die-upset hybrid magnets decreased with increasing the added R-lean alloys and showed a more profound deterioration (<5 kOe) in the die-upset magnet when the amount of R-lean alloy exceeded 20 wt%. The coercivity of the die-upset hybrid magnet is significantly lower than that of the compacted magnet, and this was due mainly to the texture development during the die-upsetting.