Inclusion agglomeration and flotation during levitation melting in a cold crucible were investigated. The morphology, number and chemical composition of inclusions were characterized by scanning electron microscopy and transmission electron microscopy with energy-dispersive x-ray spectroscopy analysis. In the billet, inclusions were mainly single mixed inclusions (oxide as the core, nitride as the shell), and their size was in the range of 1–7 μm. After levitation melting, approximately 81% of inclusions existed in the form of clusters. The number of clusters was higher at the top, and the size was larger at the top (150–250 μm). The mechanism of levitation melting removing inclusions was discussed by collision theory. First, nitrides dissolved, and the core oxides were exposed. Then, oxides collided, agglomerated, and floated. Turbulent collision played the leading role in inclusion agglomeration, while Stokes collision was predominant for inclusion flotation. Finally, nitrides precipitated again during solidification.

中文翻译：

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镍基高温合金冷坩埚悬浮熔炼过程中夹杂物团聚和浮选的研究

研究了在冷坩埚中悬浮熔化过程中夹杂物的团聚和浮选。通过扫描电子显微镜和透射电子显微镜以及能量色散 X 射线光谱分析对夹杂物的形态、数量和化学成分进行了表征。钢坯中夹杂物主要为单一的混合夹杂物（氧化物为核，氮化物为壳），尺寸在1～7 μm之间。悬浮熔炼后，大约81%的夹杂物以团簇的形式存在。顶部的簇数较多，顶部的尺寸较大（150-250 μm）。用碰撞理论讨论了悬浮熔化去除夹杂物的机理。首先，氮化物溶解，核心氧化物暴露。然后，氧化物碰撞、凝聚并漂浮。湍流碰撞在包裹体团聚中起主导作用，而斯托克斯碰撞在包裹体浮选中起主导作用。最后，氮化物在凝固过程中再次沉淀。