| NdFeB rare earth permanent magnetic material with excellent magnetic properties is widely used in electric motors, generators and other fields. Ce is a rare earth element which has high quality and costs low. When Ce was added into NdFe B. It can reduce the cost of the raw material in the NdFeB magnet, and the comprehensive utilization of the rare earth can be improved. When the NdFeB or NdCeFe B magnet is working, the eddy current will be produced, this will increase the temperature of the magne which will lead to the loss of the magnetic flux and the decrease of the working efficiency.Magnets with high resistivity which doping with CaF2 can improve the magnetic resistivity. This is an effective method to reduce the eddy current loss and can solve the problems which was caused by the increasing of the temperature of the magnet of the magnetic.The hot deformation process, doping CaF2 in NdCeFe B magnets prepared(Nd, Ce)FeB/ CaF2 anisotropy of the composite magnet, discussed the containing Ce and CaF2 on NdFe B rare earth permanent magnet’s micro structure and the influence of change and the influence and reason analysis, the conclusions of this paper are as follows:(1) Through to composite magnets in the process of rapid quenching optimized,prepared good appearance and size of the quenched ribbons. At the same time, the hot deformation composite magnets of preparation process including hot pressing temperature, thermal deformation temperature, deformation rate, and other factors influence, has carried on in the discussion. Finally to obtain the optimum process:Particle size range is 0.1 mm-0.3 mm and 550℃ hot pressing temperature, pressing pressure 300 MPa, isothermal retention pressure time is 60 s, thermorheological temperature is 850℃, the deformation rate is 10 mm / min, reduction rate is about 70%,the isothermal deformation process is about 100 s.(2) Composite magnet(Nd1-xCex) 29FebalB0.9M with CaF2 in the adding amount is3wt%, magnet remanence, maximum magnetic energy product decreased with the increase of Ce content, but the coercivity appears increased first and then decreased trend, when Ce addition is 15wt%, the coercivity reaches the maximum value 9.49 kOe.(3) When CaF2 content 3wt%, the composite magnet appeared coercivity trend is because with the increase of Ce content, Ce as low melting point elements on themicrostructure of the magnet to optimization function, resulting in the coercivity increases at first, but with the increase of Ce content, leading to the weakness between the main phase and rich rare earth phase exchange interaction, this also lead to the main phase inversion is not uniform, so the coercivity of the magnet is down again.(4) Composite magnet as doping with CaF2, magnet resistivity has been greatly improved, when CaF2 addition amount is 3wt%,(Nd1-xCex) 29FebalB0.9M(x = 0.2) hot deformation resistivity of the composite magnet increase from 230μΩ·cm to 270μΩ·cm,when the adding amount is 6 wt%, a sharp increase in the resistivity of the magnet,when the addition of CaF2 is 6 wt%, Ce content is 30% the resistivity of the magnet can be 350μΩ·cm, but magnetic properties reduced severely, in order to meet the industrial requirements the amount of CaF2 supplementation should not exceed 6%.The hot deformation of composite magnet preparation process of doped CaF2(Nd1-xCex) 29FebalB0.9M in CaF2 addition’s amount is 3%, Ce content is 15wt%, the performance optimal and remanence 11.26 kG, magnetic energy product 21.93 MGOe,coercivity reaches maximum 9.49 kOe, resistivity reaches 269μΩ·cm, which compared with magnet without doping CaF2 has increased by 13%. Through the optimization of CaF2 content and Ce content in hot pressed / hot deformed magnets, a high resistivity,low cost and high magnetic properties(Nd1-xCex) 29FebalB0.9M hot pressed / hot deformed magnet is provided. |
PDF Full Text Request