AN ELECTROSTATIC LEVITATOR FOR HIGH-TEMPERATURE CONTAINERLESS MATERIALS PROCESSING IN 1-G
AN ELECTROSTATIC LEVITATOR FOR HIGH-TEMPERATURE CONTAINERLESS MATERIALS PROCESSING IN 1-G
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DOI：
10.1063/1.1144475
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发表时间：
1993-10-01
影响因子：
1.6
通讯作者：
SPJUT, RE
中科院分区：
文献类型：
--
作者：
RHIM, WK;CHUNG, SK;SPJUT, RE
本文论述了金属及合金无容器加工高温静电悬浮技术的最新进展。首次展示了一种可在真空中悬浮金属和合金(直径2-4 mm球体)的静电悬浮技术，以及可重复使用的过热-过冷-再辉循环，同时保持良好的定位稳定性。与电磁悬浮相比，静电悬浮(ESL)具有几个重要的优点。最重要的是样品温度的宽范围，可以在不影响悬浮的情况下实现。文中还介绍了悬浮器的总体结构、电极设计、位置控制硬件和软件、样品加热、充电、制备方法和操作步骤。特别强调了样品的光电和热电子发射充电。虽然这种ESL更多地面向地面操作，但也简要介绍了微重力应用的扩展。在一个锆样(T(M)=2128K)中，系统表现出多个过热-过冷-再辉循环。这种悬浮器完全成熟后，将成为地面和空间实验室研究过冷液体的热物理性质、成核动力学、亚稳相的产生以及获得具有新特性的广泛材料的宝贵工具。
This article discusses recent developments in high-temperature electrostatic levitation technology for containerless processing of metals and alloys. Presented is the first demonstration of an electrostatic levitation technology which can levitate metals and alloys (2-4 mm diam spheres) in vacuum and of superheating-undercooling-recalescence cycles which can be repeated while maintaining good positioning stability. The electrostatic levitator (ESL) has several important advantages over the electromagnetic levitator. Most important is the wide range of sample temperature which can be achieved without affecting levitation. This article also describes the general architecture of the levitator, electrode design, position control hardware and software, sample heating, charging, and preparation methods, and operational procedures. Particular emphasis is given to sample charging by photoelectric and thermionic emission. While this ESL is more oriented toward ground-based operation, an extension to microgravity applications is also addressed briefly. The system performance was demonstrated by showing multiple superheating-undercooling-recalescence cycles in a zirconium sample (T(m)=2128 K). This levitator, when fully matured, will be a valuable tool both in Earth-based and space-based laboratories for the study of thermophysical properties of undercooled liquids, nucleation kinetics, the creation of metastable phases, and access to a wide range of materials with novel properties.