Preparation and Microscopic Evolution Analysis of High-Pressure Aerosolized Samarium Iron Alloy Powder AITranslate

［1］Hoffer G，Strnat K. Magnetocrystalline anisotropy of YCo5 and Y2Co17［J］.IEEE Transactions on Magnetics，2003，2（3）：487.

［2］（薛平，郭学益. Sm2Fe17Nx稀土永磁材料的研究现状及进展［J］.稀有金属与硬质合金，2007，35（2）：53.）

P Xue，X Y Guo. Research status and progress of Sm2Fe17Nx rare earth permanent magnets［J］.Rare Metals and Cemented Carbides，2007，35（2）：53.

［3］Kobayashi K，Iriyama T，Yamaguchi T. Magnetic properties of the single magnetic domain particles of Sm2Fe17Nx compounds［J］.Journal of Alloys Compounds，1993，193（1-2）：235.

［4］（李芳，刘颖，杨锦，高升吉，涂铭旌. 快淬法制备SmFeN稀土永磁合金粉的研究［J］.金属功能材料，2004，11（3）：1.）

F Li，Y Liu，J Yang，S J Gao，M J Tu. Preparation of SmFeN rare earth permanent magnet alloy powder by rapid quenching［J］.Metal Functional Materials，2004，11 （3）：1.

［5］Ye J W，Liu Y，Li M，Gao S J. Structural change in Sm2Fe17 alloys during homogenization and HD processing［J］.Materials Characterization，2007，58（2）：108.

［6］（马康，王清峰，宋健，初冠南. 固溶-时效对2195铝锂合金型材力学性能的影响［J］.锻压技术，2023，48（2）：203.）

K Ma，Q F Wang，J Song，G N Chu. Influence of solution-aging on mechanical properties for 2195 Al-Li alloy profile［J］.Forging & Stamping Technology，2023，48（2）：203.

［7］（王倩，李青春，常国威. 快速凝固技术的发展现状与展望［J］.辽宁工业大学学报：自然科学版，2003，23（5）：40.）

Q Wang，Q C Li，G W Chang. Present situation and prospect of rapid solidification technology［J］.Journal of Liaoning University of Technology：Natural Science Edition，2003，23 （5）：40.

［8］（叶家豪，赵云超，李洲，朱晨辉，徐流杰. 水热法制备ZrO2掺杂钨粉体过程中的粉体形貌与相转变［J］.稀有金属，2023，47（6）：825.）

J H Ye，Y C Zhao，Z Li，C H Zhu，L J Xu. Morphology and phase transition of ZrO2 doped tungsten powder prepared by hydrothermal method［J］.Chinese Journal of Rare Metals，2023，47（6）：825.

［9］（高颂，王亚宁，庞晓辉，田悦鸣. 价键理论用于分析高温合金中的痕量元素［J］.分析试验室，2023， 42（8）：1045.）

S Gao，Y N Wang，X H Pang，Y M Tian. Application of valence bond theory in the analysis of trace elements in superalloys［J］.Chinese Journal of Analysis Laboratory，2023，42 （8）：1045.

［10］（周寿增，董清飞. 超强永磁体-稀土铁系永磁材料 ［M］. 北京：冶金工业出版社，1999. 407.）

S Z Zhou，Q F Dong. Ultra-Strong Permanent Magnets-Rare Earth Ferromagnetic Materials ［M］. Beijing：Metallurgical Industry Press，1999. 407.

［11］Lee C H，Reitzr D. An experimental study of the effect of gas density on the distortion and breakup mechanism of drops in high speed gas stream［J］.International Journal of Multiphase F1ow，2000，26（2） ：229.

［12］（邓庚凤，何桂荣，邓华军，黄崛起. 还原扩散法制备钐铁氮磁性材料的组织结构与性能研究［J］.中国稀土学报，2010，28（6）：676.）

G F Deng，G R He，H J Deng，J Q Huang. Study on microstructure and properties of neodymium iron nitrogen magnetic materials prepared by reductive diffusion method［J］.Journal of the Chinese Rare Earth Society，2010，28（6）：676.

［13］（郭广顺，王明明，纪宏超，李冬冬，裴未迟，魏晨阳，史昱. 介观尺度模拟方法及其在金属材料微观组织演变中的应用［J］.塑性工程学报，2023，30（5）：1.）

G S Guo，M M Wang，H C Ji，D D Li，W C Pei，C Y Wei，Y Shi. Mesoscale simulation methods and their application to microstructure evolution of metallic materials［J］.  Journal of Plasticity Engineering，2023，30（5）：1.

［14］Andrew M M，Leane F，Robert F. Estimation of cooling rates during close-coupled gas atomization using secondary dendrite arm spacing measurement［J］.Metallurgical and Materials Transactions B，2013，44（4）：992.

［15］（顾晓倩，滕海涛，曲鹏，丁照崇，贾倩，吕保国. 微纳钨粉制备方法研究评述［J］.稀有金属，2023，47（10）：1427.）

X Q Gu，H T Teng，P Qu，Z C Ding，Q Jia，B G Lv. Review of research on synthesis methods of micro-nano tungsten powder［J］.Chinese Journal of Rare Metals，2023，47（10）：1427.

［16］Anand V，Kaufman A J，Grant N J. Rapid Solidification Processing ［M］. Baton Rouge，LA：Claitor's Publishing Division，1978. 273.

Basic Information:

DOI：10.13373/j.cnki.cjrm.XY19070014

Chinese Library Classification Number:TG146.4

Citation Information:

Sm-Fe-N system alloy materials，as the fourth-generation rare earth permanent magnet material，has both large/high magnetic moment，well thermal shock resistance/thermal stability and high Curie temperature. However，it is extremely difficult to maintain a stable chemical composition for Sm-Fe alloy in high temperature conditions due to its high melting point and volatile characteristics of Sm element. Therefore，the poor quality of Sm-Fe powder prepared through conventional processes has been one of the obstacles to develop of Sm-Fe-N permanent magnet materials. The high-pressure gas atomization technology is one of efficient routes to improve atomization quality of alloy powders，refine grain size，and inhibit element segregation. In this paper，the alloy powders with the chemical composition of 24% Sm and 76% Fe （mass fraction） were prepared in a self-design high-pressure gas atomization and rapid quenching equipment using commercial Sm and Fe element as the raw materials. The influence of process parameters on the atomization quality of alloy powders prepared under different atomization and chamber pressure conditions was discussed. The results showed that the atomization pressure had a significant effect，while chamber pressure had a less effect on the particle size of atomized powder. The appropriate process parameters of high-pressure gas atomizing Sm-Fe alloy was atomization pressure 3.0 MPa and chamber pressure 0.3 MPa. Under this process conditions，the percentage of particle size less than 40 μm of atomized Sm-Fe alloy powders was 89.94% and the average particle size was less than 25 μm. Sm-Fe alloy powders prepared under optimized process conditions were divided into 7 groups according to the particle size，and the corresponding morphology，microstructure，chemical composition，and phase constitution were characterized by means of scanning electron microscope （SEM），energy-dispersive X-ray spectroscopy （EDS） and X-ray diffraction （XRD），respectively. It was illustrated that the surface smoothness of the atomized Sm-Fe alloy powders was significantly improved，and the surface morphology changed from coarse square structure to lamellar structure with the decreasing of the atomized Sm-Fe alloy powders particle size. Besides that，the microstructure around and inside matrix evolved from coarse dendritic to fine equiaxed dendritic，which meant that the microstructure also strongly dependent on the particle size of atomized alloy powders. It was found that the reduction of particle size was beneficial to the homogeneous distribution of Sm and Fe elements in the atomized alloy powders. The atomized Sm-Fe alloy powders was mainly composed of α-Fe，Sm₂Fe₁₇，and SmFe₉ phases according to XRD results. The volatilization of Sm element in preparation process caused to a noticeable decrease of Sm₂Fe₁₇ phase with Th₂Zn₁₇-type crystal structure in atomized Sm-Fe alloy powders. The crystal structure of TbCu₇-type SmFe₉ phase tended gradually to more orderly when the particle size was less than 30 μm.