Study On The Phase Equlibria And Magnetic Properties Of Pr/Ce-Fe-B Alloy

Rare earth permanent magnet composed of rare earth metals and transition metals.As the wide application of permanent magnets,Nd-Fe-B permanent magnet are limited their developments due to resource crisis.The application of high-abundant rare-earth metals such as La,Ce,and Y with low price and abundant reserves in Nd-Fe-B permanent magnet becomes a research hotspot.Phase equilibria of RE-Fe-B alloys are fundamental information to understand the phase formation of Nd-Fe-B magnet with high-abundant rare-earth metals Ce,La and Y.In this work,phase equilibria,solidification microstructure,phase transition and magnetic properties of Pr/Ce-Fe-B alloys were studied experimentally through the diffusion couple method and the key alloy experiments.?1?The Pr/Ce-Fe-B diffusion couples annealed at 873 K for 960 hrs and the Pr-Fe-B and Ce-Fe-B alloy samples annealed at 873 K for 2400 hrs were characterized by electron microprobe,X-ray diffraction,and scanning electron microscope.Phase relations of the Pr-Fe-B and Ce-Fe-B ternary systems at 873 K were obtained finally. The ternary compounds,Ce₂Fe₁₄B,Ce_1.1Fe₄B₄,Ce₅Fe₂B₆,Pr₂Fe₁₄B,Pr_1.1Fe₄B₄ and Pr₅Fe₂B₆ were confirmed to exist be stable at 873 K,and their crystal structures were determined.?2?Ce₁₁Fe₈₂B₇,Pr₅Fe₇₅B₁₅ and Pr₁₈Fe₇₅B₇ alloy were prepared by arc melting method.The microstructure,phase formation,phase composition and phase transition temperature of as-cast alloys were analyzed by X-Ray diffraction,scanning electron microscopy and differential thermal analysis.The effect of cooling rate on the solidification structure of Ce₁₁Fe₈₂B₇ was studied.Solidification process of the alloy samples was simulated using thermodynamic calculation with Scheil model.The experimental results are consistent with the simulation results.?3?Nd_13.4Fe_79.9B_6.7?(Nd_0.9Ce_0.1)_13.4Fe_79.9B_6.7?and(Nd_0.9Pr_0.1)_13.4Fe_79.9B_6.7 ribbons were prepared by means of melt spinning method.The phase formation,microstructure and magnetic properties of the ribbons were characterized by X-ray diffraction,scanning electron microscope,and vibrating sample magnetometer.The optimal magnetic properties of Nd_13.4Fe_79.9B_6.7and(Nd_0.9Ce_0.1)_13.4Fe_79.9B_6.7 ribbons at the wheel speed of 26m/s achieved,while the magnetic properties of(Nd_0.9Pr_0.1)_13.4Fe_79.9B_6.7ribbon increase with the increase of wheel speed.