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利用机械合金化法制备Ni50Mn43Sn7磁性形状记忆合金粉末。采用X射线衍射(XRD)、扫描电镜(SEM)及振动样品磁强计(VSM)等分析手段研究了机械合金粉末的微观结构和磁性随球磨时间的变化。结果表明:在球磨过程中,依次形成一些Mn1.77Sn,MnSn2,Ni3Sn4,Ni3Sn2和Ni4Sn等中间相,随着球磨时间的增加,MnSn化合物与NiSn化合物逐渐结合而消失,球磨270h后,形成Ni2MnSn,机械合金化完成。在球磨初期,粉末晶粒尺寸急剧减小,球磨90h后晶粒尺寸基本保持稳定,颗粒以絮状团聚结构存在。由于球磨过程中粉末得到细化等原因,饱和磁化强度Ms随球磨时间的增加而减少,矫顽力(Hc)随球磨时间的增加先增大,球磨90h后急剧减小。
Preparation of Ni50Mn43Sn7 Magnetic Shape Memory Alloy Powder by Mechanical Alloying. The microstructure and magnetic properties of mechanical alloying powders were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). The results show that some Mn1.77Sn, MnSn2, Ni3Sn4, Ni3Sn2 and Ni4Sn intermediate phases are formed during the milling process. With the increase of milling time, MnSn and NiSn compounds gradually disappear. After 270h milling, Ni2MnSn, Mechanical alloying completed. In the early stage of ball milling, the grain size of the powder decreases sharply, the grain size remains stable after 90h milling, and the particles exist in the form of floc agglomeration. The saturation magnetization Ms decreases with the increase of ball milling time, and the coercive force (Hc) first increases with the increase of ball milling time and decreases sharply after 90h milling.