(中南工業(yè)大學(xué) 粉末冶金國(guó)家重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410083)
摘 要: 通過(guò)Kronmüller微磁學(xué)矯頑力模型擬合不同溫度下測(cè)得的矯頑力，分析了Sn對(duì)三元NdFeB合金和NdDyFeB合金磁性能的影響及與顯微組織的關(guān)系。發(fā)現(xiàn)摻雜Sn并未改變合金的矯頑力機(jī)制，在150 ℃以下，合金的反磁化過(guò)程由形核控制；在150 ℃ 以上，則由疇壁釘扎控制。然而，摻雜Sn卻使兩者的局部有效退磁因子Neff都減小，同時(shí)也增大了晶粒表面缺陷對(duì)矯頑力的影響。局部退磁因子減小，是NdDyFeBSn合金矯頑力提高的主要原因。而對(duì)于NdFeBSn合金，晶粒表面缺陷增大的影響超過(guò)了局部退磁因子減小的作用，故矯頑力反因Sn的存在而降低。在150℃以上，NdDyFeBSn合金中能形成更為有效的釘扎中心。
關(guān)鍵字: NdFeB磁體；摻雜；矯頑力機(jī)制；微磁學(xué)
（State Key Laboratory for Powder Metallurgy,
Central South University of Technology, Changsha 410083, P.R.China）
Abstract:The correlation of magnetic properties and microstructural improvement of NdFeB doped Sn was analyzed by fitting temperature dependence of coercivity with Kronmüller's model. Results showed that coercive mechanism is not changed by doping Sn. Beneath 150℃, nucleation controls demagnetization and pinning of domain wall determines it above 150℃. However, microstructural parameters, Neff and αK, are reduced because of doping Sn. The reduction of localized effective demagnetic field improves the coercivity of NdDyFeBSn. For NdFeBSn, decrement of coercivity by imperfections at the grain surface is larger than coercivity increment by reducing Neff. Above 150 ℃, more effective pin-site can be formed by doping Sn.
Key words: NdFeB magnet; doping; coercive mechanism; micromagnetism
