Department of Physics and Astronomy, University of Delaware, Newark, DE 19716, USA.
J Phys Condens Matter. 2010 Apr 28;22(16):164213. doi: 10.1088/0953-8984/22/16/164213. Epub 2010 Mar 30.
High-energy ball milling has been shown to be a promising method for large-scale fabrication of rare earth-transition metal nanoparticles. In this work, we report crystallographically anisotropic SmCo(5), PrCo(5) and Sm(2)(Co, Fe)(17) nanoparticles (particle size smaller than 10 nm) obtained by surfactant-assisted ball milling and study their size and properties as a function of the milling conditions. By milling nanocrystalline precursor alloys, we obtained SmCo(5) platelets (flakes) approximately 100 nm thick with an aspect ratio as high as 10(2)-10(3). The unusual shape evolution of this brittle material is attributed to its increased plasticity in the nanocrystalline state. The nanoflakes are susceptible to re-crystallization annealing and exhibit a room-temperature coercivity of up to 19 kOe. The successful fabrication of rare earth-cobalt nanoparticles and ultra-thin flakes provides hope for the development of nanocomposite permanent magnets with an enhanced energy product.
高能球磨已被证明是一种很有前途的方法，可用于大规模制备稀土-过渡金属纳米粒子。在这项工作中，我们报告了通过表面活性剂辅助球磨得到的各向异性 SmCo(5)、PrCo(5)和 Sm(2)(Co, Fe)(17)纳米粒子（粒径小于 10nm），并研究了它们的尺寸和性能与球磨条件的关系。通过研磨纳米晶前驱体合金，我们得到了厚度约为 100nm、纵横比高达 10(2)-10(3)的 SmCo(5)薄片。这种脆性材料的异常形状演变归因于其在纳米晶状态下的塑性增加。纳米薄片易于再结晶退火，并表现出高达 19kOe 的室温矫顽力。稀土-钴纳米粒子和超薄薄片的成功制备为开发具有更高能量积的纳米复合永磁体提供了希望。
