Effect of Ga Content on Magnetic Properties and Microstructure of Sintered Nd-Fe-B Magnet AITranslate

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Chinese Library Classification Number:TM273[一般工业技术]

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Sintered Nd-Fe-B magnets with different Ga contents were prepared by a powder metallurgy process.The effects of Ga content on the magnetic properties and microstructure of the sintered Nd-Fe-B magnets were systematically studied through a magnetometer,X-ray diffractometer,scanning electron microscope,energy dispersive spectrometer,electron probe microanalyzer(EPMA),and micromagnetic simulation system.The results show that the magnet with 0.4%(mass fraction)Ga addition exhibits optimal magnetic performance:its remanence Br is 13.58 kGs,coercivity Hcj is 19.71 kOe,and maximum magnetic energy product(BH)_maxis 44.63 MGOe.Additionally,its thermal stability is improved to a certain extent.The addition of an appropriate amount of Ga enhances the wettability of the grain boundary phase of the magnets,leading to formation of a continuous and smooth non-magnetic grain boundary layer and precipitation of the Nd₆Fe₁₃Ga phase.This Nd6Fe13Ga phase reduces the Fe concentration at grain boundaries,thereby decreasing the grain boundary magnetization intensity and weakening the exchange coupling among ferromagnetic grains.Consequently,the coercivity of the magnets is significantly improved.The micromagnetic simulations of demagnetization nucleation show that the addition of an appropriate amount of Ga can inhibit the agglomeration of rare earth-rich phases,effectively reduce the stray field intensity at the triangular grain boundaries and decrease the volume fraction of the triangular grain boundary phase,thereby significantly reducing the demagnetization nucleation sites,narrowing the demagnetization nucleation regions,and further significantly enhancing the coercivity of the magnets.