钴含量对烧结钕铁硼居里温度及磁性能影响规律研究

Study on the Effect of Cobalt Content on the Curie Temperature and Magnetic Properties of Sintered NdFeB

与烧结钐钴磁体相比,烧结钕铁硼稀土永磁具有优异的室温磁性能和力学性能,但其居里温度较低,只有310℃左右,限制了其在耐高温磁应用领域的使用推广。钴元素部分取代钕铁硼中的铁元素可以提高钕铁硼永磁体的居里温度,传统的钴添加方式会使磁体中形成铁钴软磁相,从而造成磁体的矫顽力大大降低。本文研究了不同钴添加量对钕铁硼磁体物相、居里温度和磁性能的影响规律,结合Al、Ga、Cu等元素对钕铁硼永磁体晶界相物相结构的协同调控作用,避免了钴元素取代铁元素过程中Fe-Co软磁相的产生。本研究制备的高钴含量钕铁硼磁体矫顽力高H_(cj)>28kOe,居里温度T_(c)>450℃,剩磁温度系数|α|20℃~100℃<0.078%/℃,矫顽力温度系数|β|20℃~100℃<0.55%/℃。

Compared with sintered samarium cobalt magnets,sintered NdFeB rare earth permanent magnets have excellent room temperature magnetic properties and mechanical properties,but their Curie temperature is lower,only about 300℃,which limits the promotion of their use in high temperature applications.Partial replacement of iron in NdFeB by cobalt can increase the Curie temperature of NdFeB permanent magnets.The conventional cobalt addition method will cause the formation of ferro-cobalt soft magnetic phase in the magnets,which will greatly reduce the coercivity of the magnets.In this paper,the influence of different cobalt additions on the phase,Curie temperature and magnetic properties of NdFeB magnets is investigated,and the synergistic control of Al,Ga,Cu and other elements on the grain boundary phase of NdFeB permanent magnets is combined to avoid the generation of Fe-Co soft magnetic phase.The high cobalt content NdFeB magents prepared in this study have high coercivity H_(cj)>28kOe,Curie temperature T_(c)>450℃,remanence temperature coefficient|α|20℃~100℃<0.078%/℃,coercivity temperature coefficient|β|_(20℃~100℃)<0.55%/℃.