电磁预处理+电磁搅拌铸造超高纯铝的晶粒细化及机理研究

(5N5) super high pure aluminum sputtering target materials are often used in semiconductor, recording medium and advanced display. Research results show that the grain size is very important for preparation and performance of film integrated circuit. Electromagnetic stirring can stir the melt out of contact, which is a reasonable method for refine super high pure aluminum. But single electromagnetic field can not refine super high pure aluminum effectively as the content of impurity elements is low and the number of heterogeneous nucleation particles is few. In this project, electromagnetic pretreatment and casting with two coils are used to refine the super high pure aluminum. One coil is located above the mold to pretreat the aluminum melt, and the overcooling induced by electromagnetic field is used to increase the number of nucleation particles. Another coil is located around the mold to play the role of stirring during the solidification process. The intense stirring caused by the electromagnetic force could break the dendrite arms near the solidification interface, and the solidification structure of super high pure aluminum could be furthermore refined. The means such as metallographic observation, chemical analysis and SEM, etc are used to study the effect of electromagnetic and mechanical fields on structure and performance of (5N5) super high pure aluminum. This project will supply a new method and thought for refining the super high pure aluminum and correlation studies, and the experimental data and theoretical foundation will be also supplied.

（5N5）超高纯铝溅射靶材常用于半导体产业、记录媒体产业和先进显示器产业。研究结果表明：靶材的晶粒尺寸对集成电路薄膜的制备和性能有很大的影响。电磁搅拌无需接触铝熔体，对于细化超高纯铝较为可行。但超高纯铝中杂质元素含量非常少，凝固的过程中异质形核核心非常少，单一电磁场对超高纯铝不能起到良好的细化效果。在本项目中，采用电磁预处理+电磁连铸的方法来制备细晶超高纯铝。一个电磁线圈布置在结晶器的上部，起预处理熔体的作用，发挥电磁场的磁致过冷作用，达到提高形核核心数量的目的。另一个线圈布置在结晶器周围，在凝固过程中起搅拌铝熔体的作用，由电磁力引起的强力搅拌，将凝固前沿的枝晶臂折断，进而进一步细化高纯铝的凝固组织。通过金相观察、化学分析、扫描电镜分析等手段考查电磁预处理+电磁搅拌对（5N5）超高纯铝组织及性能的影响。为超高纯铝晶粒细化和相关研究开辟新的方法与理念，并提供必要的理论依据和实验数据。

（5N5）超高纯铝溅射靶材常用于半导体产业、记录媒体产业和先进显示器产业。研究结果表明：靶材的晶粒尺寸对集成电路薄膜的制备和性能有很大的影响。电磁搅拌无需接触铝熔体，对于细化超高纯铝较为可行。但超高纯铝中杂质元素含量非常少，凝固的过程中异质形核核心非常少，单一电磁场对超高纯铝不能起到良好的细化效果。在本项目中，采用电磁预处理+电磁连铸的方法来制备细晶超高纯铝。一个电磁线圈布置在结晶器的上部，起预处理熔体的作用，发挥电磁场的磁致过冷作用，达到提高形核核心数量的目的。另一个线圈布置在结晶器周围，在凝固过程中起搅拌铝熔体的作用，由电磁力引起的强力搅拌，将凝固前沿的枝晶臂折断，进而进一步细化高纯铝的凝固组织。通过金相观察、化学分析、扫描电镜分析等手段考查电磁预处理+电磁搅拌对（5N5）超高纯铝组织及性能的影响。为超高纯铝晶粒细化和相关研究开辟新的方法与理念，并提供必要的理论依据和实验数据。