3D打印用(Mn,Fe)₂(P,Si,B)球形粉的制备及磁热性能研究
Synthesis and Magnetocaloric Properties of Gas-Atomized (Mn,Fe)₂(P,Si,B) Spherical Powders for 3D Printing Applications

增材制造(3D打印)作为一种新型的近净成型技术，有望实现磁制冷工质的快速、高效、复杂成型。然而，制备出球形度高、尺寸小、磁热性能优异的磁热合金球形粉是目前制约其3D打印成型的瓶颈问题。本研究采用气体雾化法成功制备出了(Mn,Fe)₂(P,Si,B)多元合金球形雾化粉，借助扫描电子显微镜、X射线衍射仪、综合物性测量系统等深入研究了其显微形貌、晶体结构、磁相变行为以及磁热性能。本研究所获得的球形粉球形度高，有望使粉料在3D打印过程具有较高的流动性；所得球形粉颗粒尺寸小、尺寸分布窄，有利于激光3D打印工件获得高致密度和高尺寸精度；第二相含量低、热滞小、熵变值大，具有优异的磁热性能。由此可见，本研究获得的球形雾化粉十分适合3D打印等新型制造领域，为室温磁制冷材料的加工和成型提供新的思路，推动其产业化之路。
Additive manufacturing (3D printing), a novel near-net shape manufacturing technique, offers a rapid and efficient way to fabricate complex magnetocaloric heat exchangers. However, the syn-thesis of magnetocaloric powders with a small particle size, spherical shape and good magnetocaloric properties becomes the bottleneck for the implementation of 3D printing. In the present work, spherical-shaped (Mn,Fe)₂(P,Si,B) magnetocaloric powders have been successfully synthesized via gas atomization. The morphology, crystal structure, magnetic phase transition behavior and the magnetocaloric properties have been studied using scanning electron microscope, X-ray diffractometer and physical property measurement system. The gas-atomized powders are highly spherical shaped, which benefits the mobility of the powders during the 3D printing process. The small particle size with a narrow size distribution is good for increasing the spatial resolution and the density of the printed heat exchangers. Besides that, the gas-atomized powders show a small thermal hysteresis and excellent magnetocaloric properties. Additionally, the weight fraction of the secondary phase is relative low in the gas-atomized powders, which will not dilute the magnetocaloric properties of the main phase. Consequently, the synthesized gas-atomized powders are well suited for the 3D printing processing, which provides a new horizon for manufacturing magnetocaloric materials and thus paves the way for magnetic refrigeration applications.