1.IntroductionIn this work Ga and Co were added inthe Nd-Fe-B alloys to increase the Curietemperature and improve the temperaturedependence.The improvement of alloy per-formance and the mechanism of coercivitywith the...1.IntroductionIn this work Ga and Co were added inthe Nd-Fe-B alloys to increase the Curietemperature and improve the temperaturedependence.The improvement of alloy per-formance and the mechanism of coercivitywith the additions of Ga and Co elementsare reported.The Curie temperature of the展开更多
本文研究了添加微量元素Si对HDDR工艺制备各向异性Nd Fe Co B Si系永磁磁粉的磁性能和磁粉结构的影响。研究结果表明 :添加Si可以显著地提高磁粉的矫顽力和各向异性 ,Si的添加可以细化晶粒 ,还能使反磁化畴难以形核 ,因而磁粉的矫顽力...本文研究了添加微量元素Si对HDDR工艺制备各向异性Nd Fe Co B Si系永磁磁粉的磁性能和磁粉结构的影响。研究结果表明 :添加Si可以显著地提高磁粉的矫顽力和各向异性 ,Si的添加可以细化晶粒 ,还能使反磁化畴难以形核 ,因而磁粉的矫顽力较高。目前对于添加Si的Nd Fe展开更多
The characteristics of novel Nd-Fe （Ni, Co, Al ）-B microstructure prepared by strip casting technique were studied. The novel microstructure was observed using scanning electron microscope （SEM） and transmission e...The characteristics of novel Nd-Fe （Ni, Co, Al ）-B microstructure prepared by strip casting technique were studied. The novel microstructure was observed using scanning electron microscope （SEM） and transmission electron microscope （TEM）. Along the direction of heat flow, there are two kinds of different microstructures. Close to the wheel side, there is a thick layer containing many polygonal Nd2Fe14B grains. Near the free surface side, however, there are relative uniform platelike Nd2Fe14B grains whose growth direction is not completely the direction of the heat flow during solidification. The formation of the novel microstructure is presumed to be the contribution of the special temperature field and Ni component.展开更多
Effect of Co substitution and annealing treatment on the formation, magnetic properties and microstructure of （NdDyTb）12.3（FeZrNbCu）81.7.xCoxB6 （x=0-15） ribbons prepared by rapid quenching and subsequent anneali...Effect of Co substitution and annealing treatment on the formation, magnetic properties and microstructure of （NdDyTb）12.3（FeZrNbCu）81.7.xCoxB6 （x=0-15） ribbons prepared by rapid quenching and subsequent annealing was systematically investigated by means of differential scanning calorimeter （DSC）, X-ray diffraction （XRD）, high resolution scanning electron microscopy （HRSEM） and vibrating sample magnetometer （VSM）. Phase analysis revealed single-phase material. The remanence polarization Jr and maximum energy product （BH）max increased with increasing x from 0 to 12 and then decreased for x=15. The intrinsic coercivity Hci of （NdOyTb）12.3 （FeZrNbCu）81.7-xCoxB6 ribbons optimally processed decreased from 1308.7 kA/m for x=0 to 817.4 kA/m for x=15. Optimum magnetic properties with Jr=1.041 T, Hci=944.9 EA/m and （BH）max=155.1 kJ/m^3 were achieved by annealing melt-spun ribbon （x=12） at 675 ℃ for 10 min. There was no significant influence of Co substitution on microstructure.展开更多
The major drawbacks of Nd-Fe-B magnets are relatively low Curie temperature and poor thermal stability. Ribbons with the near stoichiometric 2：14：1 composition of Nd10.8Dy0.75Tb0.75Fe79.7-xCoxZr0.8Nb0.8Cu0.4B6.0 （x...The major drawbacks of Nd-Fe-B magnets are relatively low Curie temperature and poor thermal stability. Ribbons with the near stoichiometric 2：14：1 composition of Nd10.8Dy0.75Tb0.75Fe79.7-xCoxZr0.8Nb0.8Cu0.4B6.0 （x=0, 3, 6, 9, 12, 15） were prepared by rapid quenching and subsequent heat treatment. The effect of Co element on the magnetic properties, thermal stability, and microstructure of the ribbons was systematically studied by vibrating sample magnetometer （VSM）, thermal magnetic analysis, atomic force microscopy （AFM）, and transmission electron microscopy （TEM）. It was found that Co substitution was significantly effective in improving the magnetic properties and the thermal stability of nanocrystalline ribbons. Although the intrinsic coercivity decreased from 1308.7 kA/m for x=0 to 817.4 kA/m for x=15, the remanence polarization and maximum energy product increased from 0.839 T and 116.5 kJ/m^3 for the Co-free samples to 1.041 T and 155.1 kJ/m^3 for the 12at% Co-substituted samples, respectively. About 10 K increase in Curie temperature was observed for the 2：14：1 phase with 1at% Co substitution. The absolute values of temperature coefficients of induction and coercivity were significantly decreased with Co substitution, which may be attractive for high operational temperature applications. The microstructure of nanocrystalline ribbons was slightly refined with Co substitution.展开更多
文摘1.IntroductionIn this work Ga and Co were added inthe Nd-Fe-B alloys to increase the Curietemperature and improve the temperaturedependence.The improvement of alloy per-formance and the mechanism of coercivitywith the additions of Ga and Co elementsare reported.The Curie temperature of the
文摘The characteristics of novel Nd-Fe （Ni, Co, Al ）-B microstructure prepared by strip casting technique were studied. The novel microstructure was observed using scanning electron microscope （SEM） and transmission electron microscope （TEM）. Along the direction of heat flow, there are two kinds of different microstructures. Close to the wheel side, there is a thick layer containing many polygonal Nd2Fe14B grains. Near the free surface side, however, there are relative uniform platelike Nd2Fe14B grains whose growth direction is not completely the direction of the heat flow during solidification. The formation of the novel microstructure is presumed to be the contribution of the special temperature field and Ni component.
文摘Effect of Co substitution and annealing treatment on the formation, magnetic properties and microstructure of （NdDyTb）12.3（FeZrNbCu）81.7.xCoxB6 （x=0-15） ribbons prepared by rapid quenching and subsequent annealing was systematically investigated by means of differential scanning calorimeter （DSC）, X-ray diffraction （XRD）, high resolution scanning electron microscopy （HRSEM） and vibrating sample magnetometer （VSM）. Phase analysis revealed single-phase material. The remanence polarization Jr and maximum energy product （BH）max increased with increasing x from 0 to 12 and then decreased for x=15. The intrinsic coercivity Hci of （NdOyTb）12.3 （FeZrNbCu）81.7-xCoxB6 ribbons optimally processed decreased from 1308.7 kA/m for x=0 to 817.4 kA/m for x=15. Optimum magnetic properties with Jr=1.041 T, Hci=944.9 EA/m and （BH）max=155.1 kJ/m^3 were achieved by annealing melt-spun ribbon （x=12） at 675 ℃ for 10 min. There was no significant influence of Co substitution on microstructure.
文摘The major drawbacks of Nd-Fe-B magnets are relatively low Curie temperature and poor thermal stability. Ribbons with the near stoichiometric 2：14：1 composition of Nd10.8Dy0.75Tb0.75Fe79.7-xCoxZr0.8Nb0.8Cu0.4B6.0 （x=0, 3, 6, 9, 12, 15） were prepared by rapid quenching and subsequent heat treatment. The effect of Co element on the magnetic properties, thermal stability, and microstructure of the ribbons was systematically studied by vibrating sample magnetometer （VSM）, thermal magnetic analysis, atomic force microscopy （AFM）, and transmission electron microscopy （TEM）. It was found that Co substitution was significantly effective in improving the magnetic properties and the thermal stability of nanocrystalline ribbons. Although the intrinsic coercivity decreased from 1308.7 kA/m for x=0 to 817.4 kA/m for x=15, the remanence polarization and maximum energy product increased from 0.839 T and 116.5 kJ/m^3 for the Co-free samples to 1.041 T and 155.1 kJ/m^3 for the 12at% Co-substituted samples, respectively. About 10 K increase in Curie temperature was observed for the 2：14：1 phase with 1at% Co substitution. The absolute values of temperature coefficients of induction and coercivity were significantly decreased with Co substitution, which may be attractive for high operational temperature applications. The microstructure of nanocrystalline ribbons was slightly refined with Co substitution.
