Abnormal variation of magnetic properties with Ce content in (PrNdCe)₂Fe₁₄B sintered magnets prepared by dual alloy method

Resource-saving (PrNdCe)₂Fe₁₄B sintered magnets with nominal composition (PrNd)_15−x Ce_x Fe₇₇B₈ (x = 0−10) were prepared using a dual alloy method by mixing (PrNd)₅Ce₁₀Fe₇₇B₈ with (PrNd)₁₅Fe₇₇B₈ powders. For Ce atomic percent of 1% and 2%, coercivity decreases dramatically. With further increase of Ce atomic percent, the coercivity increases, peaks at 6.38 kOe in (PrNd)₁₁Ce₄Fe₇₇B₈, and then declines gradually. The abnormal dependence of coercivity is likely related to the inhomogeneity of rare earth chemical composition in the intergranular phase, where PrNd concentration is strongly dependent on the additive amount of (PrNd)₅Ce₁₀Fe₇₇B₈ powders. In addition, for Ce atomic percent of 8%, 7%, and 6% the coercivity is higher than that of magnets prepared by the conventional method, which shows the advantage of the dual alloy method in preparing high abundant rare earth magnets. (paper)