纳米复合永磁合金Nd_9Fe_(85-x)B_6Mn_x的XAFS研究

XAFS Studies of Nd_9Fe_(85-x)B_6Mn_x Nanocomposite

为了研究淬火速度及 Mn掺杂对纳米复合 Nd- Fe- B磁性材料微结构的影响 ,利用 XAFS技术对不同淬火速度的 Nd9Fe84.5B6Mn0 .5样品及退火和未退火的 Nd9Fe85-x B6Mnx( x=0 .5和 1 .0 )样品 ,进行了 Fe原子局域结构的分析。结果表明 ,纳米复合 Nd9Fe84.5B6Mn0 .5磁性材料随着淬火速度的增加 ,Fe原子的最近邻配位距离单调减小 ,而配位无序度的变化较为复杂。退火前 ,掺杂微量 Mn原子进入磁体的 Nd2 Fe14 B主相晶体结构 ,掺杂量不同对主相局域结构的影响有明显差异。退火后 ,Mn原子退出磁体的主相结构 ,进入晶界或产生富集 ,没有发现掺杂量不同对主相局域结构的影响 。

In order to study the effect of Mn addition and quenching speed on Nd Fe B alloy, the local structures of the Nd 9Fe 85 x B 6Mn x ( x =0.5 and 1.0)nanocomposite manufactured at different quenching speed and under different annealing condition have been investigated by XAFS. It is showed that the first coordination distance of Fe atom in the Nd 9Fe 84.5 B 6Mn 0.5 alloy decreases with the quenching speed, and the change of the disorder factor is complex. Before annealing some Mn atoms enter main lattice of the Nd 9Fe 85 x B 6Mn x (x =0.5 and 1.0) nanocomposite,and its effect on main lattice is different for x =0.5 and 1.0.Afert annealing the structures of main lattice are same for x =0.5 and 1.0 because of Mn leaving,but the effect of Mn atoms on the magnetism of the Nd 9Fe 85 x B 6Mn x nanocomposite is different for x =0.5 and 1.0.