(Nd,Dy)13.5Fe80B6.5合金铸片的微结构研究

研究了铸片工艺制备的(Nd,Dy)13.5Fe80B6.5铸片的微结构。结果表明:铸片主要由2∶14∶1相片状晶组成且存在明显的择优取向,晶粒沿[00l]方向择优生长;取向度随轮速改变发生明显的变化,在v=1.5～2m·s-1时取最大值。当v=2m·s-1时铸片由厚度约3μm、且被0.2～0.5μm的富Nd相薄层隔开的2∶14∶1相片状晶组成,铸片中不存在α Fe枝状晶。     

纳米复合永磁材料的有效各向异性与矫顽力

研究了纳米Nd2Fe14B/α-Fe复合永磁材料中晶粒交换耦合相互作用对有效各向异性的影响和变化规律.结果表明：晶粒之间的交换耦合作用使材料的有效各向异性Keff随晶粒尺寸的减小而下降、随软磁性相成分的增加而降低. 当晶粒尺寸 减小到4nm时，Keff值减小为其各自通常各向异性常数值的1/3—1/4.有效各向异性的变化特点与矫顽力的变化规律基本相同.纳米复合永磁材料矫顽力的降低主要由于有效各向异性的减小而引起. 关键词： 纳米复合永磁材料 交换耦合相互作用 有效各向异性 矫顽力     

Effective anisotropy and coercivity in nanocrystalline single-phase NdFeB permanent magnetic material

The effect of exchange-coupling interaction on the effective anisotropy and its varying tendency in nanocrystalline single-phase NdFeB permanent magnetic material have been investigated. The results show that the exchange-coupling interaction between grains makes the effective anisotropy of material, Keff, decrease with the reduction of grain size. The variation of Keff is basically the same as that of coercivity. The decrease in effective anisotropy is the main reason of the reduction of coercivity for nanocrystalline single-phase NdFeB permanent magnetic material. In order to get high anisotropy and coercivity in nanocrystalline single-phase NdFeB permanent material, the grain size should be larger than 35 nm.