Present and Future Capabilities of Acoustic Levitation and Positioning Devices

The techniques of acoustic positioning without the use of resonant cavities have been explored and developed over a number of years and the currently available capabilities are reviewed. The performance and characteristics of these nonresonant acoustic systems are described in regard to containerless processing with emphasis on the low-g environment. This includes manipulation and mixing of liquid drops, super-cooling phenomena, heating to temperatures of 1600° C or higher, rapid cooling solidification, and surface shape control. Some possible applications are measurements of physical properties of substances at high temperatures or of highly reactive specimens, and the formation of unique glasses and alloys of new compositions.