NdFeB/SmCo_5复合永磁体界面反应规律研究  

Interface Reaction Law of NdFeB/SmCo_5 Composite Permanent Magnets

作　　者：崔熙贵[1] 王兴华 崔承云[1] 潘金鑫 梅鹏 彭希超 

机构地区：[1]江苏大学机械工程学院,江苏镇江212013

出　　处：《稀有金属》2017年第11期1224-1230,共7页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(51401087);中国博士后科学基金特别资助项目(201104511)资助

摘　　要：对NdFeB/SmCo_5复合永磁体界面反应可能生成的合金相及其形成能力进行了分析,以控制NdFeB和SmCo_5两硬磁相间的界面反应,有效改善复合磁体的磁性能。利用Miedema理论和几何外推模型,计算了NdFeB/SmCo_5复合体系可能反应生成的系列合金相的形成焓,分析了2∶14∶1和1∶5两硬磁合金相的元素替代规律,得出了NdFeB与SmCo_5间的界面反应热力学规律。结果表明:2∶14∶1和1∶5合金相的形成焓随稀土元素改变而变化,且1∶5合金相的形成焓更负;SmCo_5合金相较Nd2Fe14B合金相更稳定,但是稀土含量为33.3%的SmCo_2合金相的形成焓更负,其形成能力优于SmCo_5合金相;Nd(或Pr)或Fe取代SmCo_5合金相中的Sm或Co后增大了其形成焓,降低了1∶5相的形成能力;然而,Sm或Co取代Nd_2Fe_(14)B合金相中的Nd或Fe反而使2∶14∶1相的形成焓更负,增强了其形成能力。Nd_2Fe_(14)B合金相转变成Nd_2Co_(14)B合金相的热力学驱动力要显著高于其转变成Sm_2Fe_(14)B合金相的,使得Nd_2Fe_(14)B合金相优先发生界面反应形成Nd_2(Fe,Co)_(14)B合金相,而SmCo_5合金相则倾向于形成更稳定的SmCo_2合金相。The alloy phases possibly produced by interface reaction and their formation ability were analyzed to control the interface reaction between NdFeB and SmC% hard magnetic phases and effectively improve the magnetic properties of composite magnet. The formation enthalpies of alloy phases possibly produced in NdFeB/SmC% composite system were calculated by using Miedema theory and the geometric extrapolation model. The element replacement laws of 2： 14：1 and 1：5 hard magnetic alloy phases were analyzed, obtaining the thermodynamic law of interface reaction between NdFeB and SmCo5. The results showed that, the formation enthalpies of 2： 14：1 and 1：5 alloy phases changed with rare earth elements variation, and the formation enthalpy of 1：5 alloy phase was more negative. SmC% alloy phase was more stable than Nd2Fe14B alloy phase, but the formation enthalpy of SmCo2 alloy phase with 33.3% rare earth element was more negative, the formation ability of which was better than that of SmCo5 alloy phase. Its formation enthalpy increased after replacement of Sm or Co in SmC% alloy phase by Nd （ or Pr） or Fe, thereby reducing the formation ability of 1 ： 5 phase. However, the formation enthalpy of 2： 14：1 phase became more negative after the replacement of Nd （or Pr） or Fe in Nd2Fel4B alloy phase by Sm or Co, increasing its formation ability. The thermodynamic driving force of Nd2Fe14 B alloy phase transforming to Nd2 Co14 B alloy phase was significantly higher than that of Nd2 Fe14 B alloy phase transforming to Sm2 Fe14 B alloy phase, making Nd2 Fe14 B alloy phase preferentially undergo interface reaction to form Nd2 （ Fe, Co） 14B alloy phase. While SmCo5 alloy phase tended to form more sta- ble SmCo2 alloy phase.

关 键 词：复合永磁体 MIEDEMA理论 形成焓 界面反应 

分 类 号：TM273[一般工业技术—材料科学与工程]