纳米晶复合Pr_2Fe_(14)B/α-Fe快淬薄带的织构与磁性

Texture and magnetic properties of nanocomposite Pr_2Fe_(14) B/α-Fe melt-spun ribbons

采用快淬方法制备了纳米晶复合Pr2Fe14B/α-Fe永磁薄带,研究了不同淬火速率对薄带织构和磁性的影响.通过改善快淬工艺,使得薄带中Pr2Fe14B相的晶粒在薄带的自由面形成显著的织构,Pr2Fe14B相晶粒易轴沿垂直于带面方向取向.分析了快淬凝固过程中Pr2Fe14B相的晶粒取向过程和机理,以及晶粒的大小和薄带结构的均匀性对薄带磁性的影响.对自由面有显著取向的薄带,进行酸蚀和打磨减薄处理,去除贴辊面未取向的部分,剩余部分为具有Pr2Fe14B相晶粒取向的各向异性薄带,Pr2Fe14B相取向使薄带的剩磁得到增强,矫顽力也有所提高.

The effect of quenching rate on texture formation and magnetic properties of nanocomposite Pr2Fe14 B/α-Fe melt-spun ribbons has been investigated. The c-axis texture of Pr2 Fe14 B phase perpendicular to the ribbon plane was found on free surface of melt-spun ribbons prepared by optimized melt-spun technique. The formation of c-axis texture mainly result from the crystallites of Pr2 Fe14 B growing up along the flow of heat, which is induced by the contact of melt alloy with the surface of Cu wheel. The texture of Pr2Fe14 B phase does not penetrate through the thickness of melt-spun ribbons, and the incompletely textured structure does not bring about remanence enhancement. Anisotropic nanocomposite Pr2Fe14B/α-Fe ribbons were obtained by eliminating the unaligned part of the ribbons melt-spun at 16 m/s through acid-etching and polishing the side of ribbons in contact with the roller surface during spinning. Both Br and i Hc of the anisotropic ribbon measured along the direction perpendicular to the plane were improved obviously due to the c-axis alignment of Pr2 Fe14 B phase.