低能球磨制备Mn55Bi45永磁合金的微结构及矫顽力机理研究

Microstructure and coercivity mechanism of Mn 55 Bi 45 permanentmagnetic alloys prepared by low energy ball milling

目的:通过研究Mn 55 Bi 45永磁合金球磨制备方法和矫顽力机理,从而获取高性能Mn 55 Bi 45永磁合金。方法:采用低能球磨制备LTP-MnBi粉末,通过微结构和磁化行为分析,研究了合金粉末的相组成、磁性能及矫顽力机理。结果:研究表明LTP-MnBi粉末矫顽力大小与晶粒大小有密切关系,随着球磨时间的增加,内禀矫顽力先增大后减小。结论:通过4 h低能球磨,Mn 55 Bi 45粉末表现出最佳磁性能,内禀矫顽力为13.2 kOe,饱和磁化强度为37.1 emu/g,最大磁能积3.6 MGOe。通过FORC分析Mn 55 Bi 45矫顽力变化机理,Mn 55 Bi 45粉末的矫顽力变化可归结为Mn 55 Bi 45晶粒细化的结果。

Aims:The ball milling method and coercivity mechanism of Mn 55 Bi 45 permanent magnetism alloys were investigated to obtain high performance Mn 55 Bi 45 PM alloy.Methods:Low-energy ball milling was used to prepare LTP-MnBi powder.The phase composition,the magnetic properties and the coercivity mechanism of the alloy powder were investigated by the microstructure and magnetization behavior analysis.Results:The results showed that the coercivity of LTP-MnBi powder was closely related to the grain size;and the coercivity increased and then decreased with the increase of ball milling time.Conclusions:Through 4 hours of low energy ball milling,Mn 55 Bi 45 powder showed the best magnetic properties,an endowed coercivity of 13.2 kOe,a saturation magnetization intensity of 37.1 emu/g,and the maximum magnetic energy product of 3.6 MGOe.Through FORC analysis of the Mn 55 Bi 45 coercivity change mechanism,the coercivity of Mn 55 Bi 45 powder changes can be attributed to the results of Mn 55 Bi 45 grain refinement.