Two-phase microstructure in Pr-(Fe, Co, Ni)-B sintered magnets

A search was carried out for a two-phase sintered magnet comprising Pr₂TM₁₄B and PrTM, where TM stands for Fe, Co and Ni. Specimens were prepared by a powder metallurgical method using alloys with compositions Pr₁₇(Fe_0.6Co_0.3Ni_0.1)₈₃−_χB_χ (x = 4, 5 and 6). X-Ray diffraction and scanning electron microscopy—energy-dispersive X-ray studies have revealed that two-phase magnets are realized for Pr₁₇(Fe_0.6Co_0.3Ni_0.1)₇₈B₅. The microstructures of these sintered magnets are characterized by Pr₂TM₁₄B grains surrounded by an intergranular Ni-rich PrTM phase whose thickness is less than about 3 μ.