SmCo5/Fe7Co3高温永磁复合材料的纳米相结构与磁性能

Using the AAO membrane with different nanometer-sized aperture as a template, electrochemical alternating deposition with hard and soft phase is used to fabricate SmCo5 / Fe7Co3 multilayered nanowires with a high curie point and a good crystal orientation on the template, and then AAO template is taken off, so the nanowires with two-phase layer in about 10 nm thickness of each layer and direct atom contact on the duplex interfaces are carried out. Finally, the magnetic composite powders being close to theoretical model are prepared by SmCo5 / Fe7Co3 multi-layer duplex nanowires. Through the study on the alternating nucleation and growth mechanism of the hard and soft two-phase, we want to theoretically clarify the growth mechanism of hard and soft magnetic two-phase nanocrystalline with an ideal parallel orientation, uniform and formal features; by optimizing the nano-phase structure and interface microstructure of this new type of permanent magnet materials, it results in that the microstructure of SmCo5 / Fe7Co3 multi-layer duplex nanowires is closer to the theoretical model of two-phase nano-permanent magnetic materials. Through the study on the variation mechanism on the magneto-crystalline anisotropy of composite permanent magnet corresponding to thickness changes of the hard and soft magnetic two-phase nanocrystalline layer under the variable temperature conditions, we are going to reveal the law and relationship between the nano-phase structures and interface exchange coupling, to clarify the impact mechanism of microstructure optimization on the anisotropy of hard magnetic phase and magnetic properties of the nano duplex permanent magnet composite powders in the high temperature, to solve the bottleneck scientific problem that the high temperature magnetic properties of nano duplex composite permanent magnet is generally lower at present, which will provide a theoretical basis for the development of new type of high temperature permanent magnets with high magnetic properties.

以不同纳米尺寸孔径的AAO膜为模板，采用电化学软硬相交替沉积法制备取向性好的高居里点的SmCo5/ Fe7Co3多层纳米线，脱去AAO模板，制成软硬两相层厚皆为10纳米左右，双相界面原子直接接触的纳米线，然后将SmCo5/ Fe7Co3多层双相纳米线制成趋近理论模型的复合磁粉。通过研究软硬双相的交替形核长大机制，从理论上阐明软硬磁双相纳米晶体实现理想平行取向、均匀、规则的生长机理；通过优化这种新型永磁材料的纳米相结构和界面微结构，使其符合双相纳米永磁材料的理论模型；通过研究变温条件下复合永磁体的磁晶各向异性随软硬磁双相纳米晶层厚度不同而变化的机理，揭示其纳米相结构与界面交换耦合作用的关系与规律，从而阐明新型纳米双相永磁体微结构优化对高温下硬磁相的各向异性常数和复合磁粉磁性能的影响机理，以解决目前双相纳米复合永磁体的高温磁性能普遍偏低的瓶颈科学问题，为研制新型高磁性能高温永磁体提供理论依据。

项目采用纳米阵列模板和直流电化学软硬相交替沉积晶体生长方法制备出了取向性较好、软硬两相层厚皆为10～20nm的三种Sm-Co/Fe-Co双相纳米线。通过对其晶体结构、形貌、物相组成以及室温及高温磁性能测试与表征、分析和讨论，得到主要创新性结论如下：. (1) XRD分析结果表明：沉积态的Sm-Co/Fe-Co双相纳米线中Sm-Co合金为非晶结构，而Fe-Co相为晶体结构。退火后的Sm-Co/Fe-Co双相纳米线转变为多晶结构。.(2)SEM/EDS分析结果表明：在低分辨率下，三种工艺方法制备所得的Sm-Co/Fe-Co双相纳米线的形貌与单相Sm-Co纳米线类似；随着Sm-Co溶液沉积时间的缩短，双相纳米线中Sm和Co元素的含量减少，Fe元素含量相对增多。.(3)透射电镜分析结果表明：沉积态的Sm-Co/Fe-Co双相纳米线线径均匀一致。衍射光环表明沉积态的双相纳米线并不是完全的多晶组织。高分辨透射电镜观察到经过660℃退火的Sm-Co/Fe-Co双相纳米线的两相界面原子实现了表面配位，产生了共面结构，正是这种界面微结构产生了界面弹性交换耦合作用。.(4)常温VSM分析结果表明：退火后，三种工艺制备出的Sm-Co/Fe-Co双相纳米线的剩磁比和矫顽力均得到很大的提高，但饱和磁化强度有所降低；当硬磁相含量较多，软磁相含量较少时，双相纳米线的饱和磁化强度、矫顽力和剩磁比更大，故制得双相纳米线工艺方法Ⅰ为最优的Sm-Co/Fe-Co双相纳米线的制备工艺。.(5)双相纳米线的从室温到1000℃高温的热磁曲线和VSM分析研究测试结果表明，随着温度的升高，其矫顽力和剩磁比先升高后降低，且在700℃时矫顽力的值达到最大，其饱和磁化强度则随温度升高而降低。在700℃的高温下，仍具有较高的热稳定性，是一种很好的高温永磁复合材料。