Nd-Fe(Co,Nb)-B交换耦合磁体的磁性

用熔体快淬法结合热处理制备了高性能纳米复合永磁合金Nd₉Fe_85.5-xCo_xNb₁B_4.5(0≤x≤16).最佳磁性能对应的成分为Nd₉Fe_81.5Nb₁B_4.5,其永磁性能如下：最大磁能积(BH)_max＝156kJ/m³,剩磁J_r＝1.11T 关键词：

MAGNETIC PROPERTIES OF Nd-Fe(Co,Nb)-B EXCHANGE COUPLING MAGNET

The melt spun ribbons of nanocomposite Nd₉Fe_85.5-xCo_xNb₁B_4.5(x＝0-16) have been prepared by rapid quenching and post heat treatment. The best magnetic properties obtained in Nd₉Fe_84.5Nb₁B_4.5 ribbons are as follows:(BH)_max＝156kJ/m³,J_r＝1.11T and μ₀H_cJ＝0.68T.It is shown that the melt spun ribbons consist of both 2∶14∶1 compound and α-Fe(Co,Nb) phases with mean grain sizes smaller than 30nm. The effect of exchange coupling between the nanostructure grains of Nd₂(Fe,Co,Nb)₁₄B and α-Fe(Co,Nb) are observed clearly. The Curie temperature enhancement is about 10K and the largest reduced remanence achieved 0.776.It is also indicated that there is a close relation between the reduced remanence and the mean grain size of α-Fe phase. The smaller the mean grain size of α-Fe phase, the greater the remanence enhancement. The Curie temperature of the melt spun ribbons increases quickly with a rate of 11.3K/at%. The coercivity, remanence and maximum energy product decrease monotonically with increasing Co content for the Nd₉Fe_85.5-xCo_xNb₁B_4.5 ribbons.