Improvement in Coercivity of Nd-Fe-B Melt-spun Ribbons with the Addition of Nd-Cu Alloys

Abstract

Nd₁₅Fe₇₇B₈,Nd₄Fe_77.5B_18.5,and R-Cu (R=Nd, Pr, Sm, Ce) eutectic alloys were produced by the melt-spinning technique. The Nd-Fe-B alloys mixed with the Nd-Cu alloy were annealed to examine the effects of the Nd-Cu alloy on the coercivity of the Nd-Fe-B alloys. The coercivity of the Nd-Fe-B alloy increased as the amount of the Nd-Cu alloy increased. The Nd₁₅Fe₇₇B₈ alloy mixed with 30% Nd-Cu alloy exhibited an unusually high coercivity of 29.2 kOe after annealing at 873 K for 1 h. It was found that the coercivity of the Nd₄Fe_77.5B_18.5 alloy was also increased by the addition of Nd-Cu alloys. The Nd₄Fe_77.5B_18.5 alloy mixed with 40% Nd-Cu alloy showed a coercivity of 4.6 kOe after annealing at 923 K for 1 h.