摘要
采用快淬加后续晶化退火方法,制备了NdFeB/α-Fe双相纳米晶复合永磁合金的快淬态和晶化态薄带,用原子力显微镜(AFM)观察了薄带贴辊面和自由面的微观形貌,分析研究了薄带不同表面晶粒尺寸与均匀性的差异。贴辊面快淬时冷却速度快、结晶度高,快淬态主要由非晶体组成,退火时新相的析出以均匀形核的方式成核,晶化态晶粒数量少、平均尺寸(～70nm)大,但晶粒大小均匀。自由面快淬时析出了数量较多、尺寸较大的微晶,退火时以非均匀形核为主,成核率高,晶粒数量多、尺寸小,平均晶粒尺寸(～50nm)小于贴辊面,但由于微晶本身的长大,形成了超过100nm的粗大晶粒,使微观结构的均匀性变差。薄带不同表面微观形貌的差异将会对纳米晶复合永磁材料的磁性能产生直接的影响。
The ribbons of NdFeB/α-Fe composite alloy were prepared by melt spinning and post crystallizing. The morphologies of wheel side surface and free side surface of ribbons were observed by AFM. The grain size and uniformity on different surfaces were investigated The component near the wheel side surface of as-spun ribbons is mainly amorphous due to high cooling rate. The mechanism of new crystal precipitation is homogeneously nucleating during crystallization annealing. So the lower nucleation rate results in a smaller grain quantity and a bigger average grain size（-70 nm）. But the grains are uniform. On the free side surface, precursors have a higher crystallinity. A large amount of fine crystallites result in heterogeneously nucleating of the newly crystal during the crystallization. The higher nucleation rate and larger grain quantity decrease the average grain size to -50 nm. But the microstructure is nonuniform and the coarse grains （over 100 nm ） appear due to the old crystallite growing. The differences between grain size and uniformity on different surfaces may affect the magnetic properties of NdFeB/a-Fe composite alloy.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2010年第A01期174-176,共3页
Rare Metal Materials and Engineering
基金
四川省特种材料及制备技术重点实验室基金资助
