纳米晶Nd10.5Pr2.5Fe80Nb1B6快淬薄带织构及其形成机制  

Texture Forming Mechanism of Nanocrystalline Nd_(10.5)Pr_(2.5)Fe_(80)Nb_1B_6 Melt-Spun Ribbons

作　　者：张勇[1] 王艳[1] 刘新才[1] 潘晶[1] 王红玉[1] 潘建峰[1] 董友仁[1] 龙能兵[1] 李天华[1] 

机构地区：[1]宁波大学材料科学与化学工程学院,宁波市新型功能材料及其制备科学重点实验室,浙江宁波315211

出　　处：《中国稀土学报》2016年第1期24-32,共9页Journal of the Chinese Society of Rare Earths

基　　金：国家自然科学基金项目(51174121和51274125);浙江省重点科技创新团队项目(2012R10016-08);宁波大学王宽诚幸福基金资助

摘　　要：采用熔体快淬法制备了Nd10.5Pr2.5Fe80Nb1B6快淬薄带,利用X射线衍射、扫描电镜分析了快淬薄带的显微组织,并用振动样品磁强计测量了其磁性能,分析了磁织构的形成机制。实验结果表明：Nd10.5Pr2.5Fe80Nb1B6快淬薄带在快淬速度为5～20 m·s^-1时,薄带自由面形成[006]磁织构、峰强比I（006）/I（410）为26.95～69.08,快淬薄带破碎小颗粒树脂2 T磁场固化样品的约化剩磁比为0.69～0.74,内禀矫顽力Hci=375.84～712.48 kJ·m^-3,最大磁能积（BH）max=105.58～157.30 kJ·m^-3;薄带沿与[006]织构垂直的方向测量的约化剩磁比为0.35～0.47,后者的磁能积只有前者的30%～43%。对于合适成分的钕铁硼合金,当钕铁硼熔体温度接近其熔点,熔体受辊触发以极快速度形成等轴晶、薄带自由面难以择优取向;提高钕铁硼熔体温度,在低快淬速度时在贴辊面孕育出强各向异性纳米晶等轴晶甚至可能形成织构,在等轴晶区之上生长柱状晶区具有[006]磁织构;当快淬速度增加,贴辊面不足以形成磁织构、但具有择优取向,如柱状晶区具有占整个薄带厚度的足够空间,能发展出自由面的磁织构;随着快淬速度的进一步增加,柱状晶区厚度减小,自由面难以形成织构;当快淬速度再增加时,薄带易形成非晶。Nd10.5Pr2.5Fe80Nb1B6 ribbons were melt-spun at different wheel speeds 5 ～ 35 m·s^-1,and were analyzed by X ray diffraction,scanning electron microscopy,and measured by vibrating sample magnetometer. Their magnetic texture forming mechanism was discussed. The results showed that there was [006] magnetic texture of（ NdPr）2Fe14B phase near the free surface of Nd10.5Pr2.5Fe80Nb1B6 ribbons melt-spun at the wheel speed 5 ～ 20 m·s^-1,with the peak intensity ratio I（ 006）/ I（ 410）26. 95 ～ 69. 08. The reduced remanence ratio of particle-resin cured in 2 T magnetic field,of the ribbons,Mr/ Ms,is 0. 69 ～ 0. 74,the intrinsic coercive force,Hci,375. 84 ～ 712. 48 kJ·m^-3,the maximum energy product,（ BH）max,105. 58 ～ 157. 30 k J·m^-3. And the ratio of the ribbons,measured in the direction perpendicular to the [006]texture,was 0. 35 ～ 0. 47,their maximum energy product was only 30% ～ 43% of the particle-resin. To the ribbons with the appropriate compositions,such as Nd10. 5Pr2. 5Fe80Nb1B6,the [006]texture forming mechanism would be as follows. When the melt temperatures of the ribbons were close to their melting points,the whole melt will be triggered by the roll,to form the equiaxed grains without any preferred orientation. To increase the melt temperature so the melt cooling rate was raised,if the wheel speed is enough low,the high melt cooling rate made the ribbon near the wheel surface nurture equiaxed nanocrystals with strong anisotropy,even with the [006] texture; and the columnar grain zone with the texture within the ribbon near the free surface are developed over the equiaxed grain zone. And in the ribbons near both to the wheel surface and the free surface,the [006] texture will be obtained. As the wheel speed was increased,the ribbon near the wheel surface was not enough to form a magnetic texture,but with preferred orientation; and the columnar grain zone with the[006]magnetic texture can be formed only the zone with enough space of the total ribbon thickness. The higher the wheel

关 键 词：快淬薄带 织构 织构形成机制 磁性能 微观组织 稀土永磁材料 

分 类 号：TG294[金属学及工艺—铸造]