摘要
用熔体快淬法制备了高性能纳米双相耦合Nd2Fe14B/α Fe磁体,研究了快淬速率和热处理工艺对其磁性能和微结构的影响。实验结果表明,控制快淬速率在12m·s-1时,可直接得到显微组织均匀、α Fe相粒子细小且均匀分布的纳米双相耦合Nd2Fe14B/α Fe磁体。低温退火处理后可消除由少量非晶相带来的成分不均匀性,其最高磁性能为iHc=432.2kA·m-1,Jr=1.08T,(BH)max=115kJ·m-3。快淬速率提高,非晶相体积分数增加,在高温晶化热处理时软硬磁相析出不均匀,个别α Fe相粒子奇异长大,尺寸达到100nm左右,这不利于软硬磁相间的交换耦合作用,有损磁性能。
Nanocomposite Nd 2Fe 14 B/α Fe magnets have been synthesized by melt spinning a Nd 8Fe 86 B 6 alloy and the effect of wheel speed and annealing process on their magnetic properties and microstructure has been investigated. The results show that there is an optimum wheel speed about 12 m·s -1 at which a homogeneous Nd 2Fe 14 B/α Fe microstructure with fine α Fe grains is developed directly from the melt. After low temperature annealing, the non uniform composition from amorphous is eliminated and the magnetic properties can increases. The maximum magnetic properties are: iH c=432.2 kA·m -1 , J r=1.08 T, ( BH ) max =115 kJ·m -3 . However, higher wheel speed leads to the appearance of amorphous phase and its volume fraction increases with the increase of wheel speed. These result in a Nd 2Fe 14 B/α Fe structure with large α Fe grains after a subsequent crystallization annealing, which deteriorates the exchange coupling between Nd 2Fe 14 B phase and α Fe phase and decrease its magnetic properties.
出处
《中国稀土学报》
CAS
CSCD
北大核心
2002年第z2期71-75,共5页
Journal of the Chinese Society of Rare Earths
基金
国家重点基础研究发展规划项目(973)"纳米材料和纳米结构"G1999064508
教育部科学技术重点项目资助课题
关键词
稀土
纳米复合磁体
交换耦合
矫顽力
rare earths
nanocomposite magnets
exchangse coupling
coercivity
