Application of a plate sonotrode to ultrasonic degassing of aluminum melt: Acoustic measurements and feasibility study

A flat plate sonotrode was used for ultrasonic melt processing (degassing) of aluminum melts. Calculations showed that this sonotrode should have several antinodes with maximum amplitude, spaced at 16.5 mm. The direct measurements of the amplitude in air and indirect measurements of foil cavitation erosion in water validated these calculations. Unique acoustic measurements of cavitation activity in water and a liquid aluminum alloy were performed using a cavitometer and confirmed that the cavitation conditions were met with this scheme. The melt degassing efficiency using the plate sonotrode was significantly higher (70-80%) than with a conventional cylindrical sonotrode (45-50%) in batch operation. The new scheme was also suitable for ultrasonic melt processing in the melt flow giving about 50% degassing efficiency, which opens the way to upscaling this technology to treat larger volumes of melt.