Ultrasonic Irradiation of a Surface: The Best Energetic Ratio, the Most Difficult Reactor Design - Applications in Sonoelectrochemistry

• Published in: Meeting abstracts (Electrochemical Society) Vol. MA2025-01; no. 24; p. 1438
• Main Authors: Hihn, Jean-Yves, Hallez, Loic, Pflieger, Rachel, Pollet, Bruno Georges
• Format: Journal Article
• Language: English
• Published: The Electrochemical Society, Inc 11.07.2025
• ISSN: 2151-2043; 2151-2035
• DOI: 10.1149/MA2025-01241438mtgabs

The most common use of ultrasound in surface irradiation is to clean or degrease components such as jewelry, lenses or other optical parts, dental and surgical instruments, and electronic equipment [1]. But the use of ultrasound in electrodeposition has also been the subject of numerous claims since the 1950s and several authors [2, 3] have reported the beneficial effect of ultrasound in metal plating. This is particularly competitive as it can lead to a reduction in the use of chemical additives or even their complete elimination. They also report that plating in an ultrasonic field can produce coatings with increased hardness and brightness, better substrate adhesion, finer grain and reduced porosity and internal stress. Most of these properties are in direct relationship with the coating microstructure in terms of grain size and crystalline organization, which becomes therefore a major issue [4], and for once, the energy loss/beneficial effects ratio is rather positive [5]! Although the potential of sonochemistry in surface application is very interesting, it has not been industrialized on a large scale. Almost all the above cases offer high added value, but with little energy considerations. This can be a major barrier to the scale-up. To overcome this problem, pioneers works deal with the sonoreactors characterization, using global and local techniques, which allow a good prediction of the acoustic field, and by extension, lead to better reactor design [6]. On this occasion, an original physical parameter was designed to predict local agitation depending of the geometrical configuration: an equivalent flow normal to the surface [7] and a tangential flow. These new tools have made it possible to make better uses of several developments, including modifications of the transducer shape. For example, increasing the frequency level causes a reduction in transducer thickness, which is the known limit for energy per surface. It is then possible to focus the acoustic energy by changing the transducer shape. High-Intensity Focused Ultrasound transducers, as their name suggests, are capable of concentrating the acoustic energy at the focal point, which can be advantageous for high-energy chemical applications [7]. Finally, the most recent advances in sonoreactor optimization are the use of frequency sweeps to probe acoustic cavitation activity. An unprecedented enhancement or quenching of cavitation activity was observed when short frequency sweep gaps were applied in negative and positive directions, respectively. It was found that, irrespective of the frequency gap, it is the direction and frequency sweep rate that governs cavitation activity [8, 9]. This will open up considerable opportunities for a wide range of applications, including controlled surface erosion [10] and conducting polymers [11]. [1] G. Mazue, R. Viennet, J-Y. Hihn, L. Carpentier, P. Devidal, I. Albaïna Ultrason. Sonochem., 18(4) 895–900, 2011 [2] C.T. Walker, R. Walker, Electrodepos. Surf. Treat. 1 (1973) [3] F. Touyeras, J.Y. Hihn, X. Bourgoin, B. Jacques, L. Hallez, V. Branger, Ultrason. Sonochem. 12 (2005) [4] A. Nevers, L. Hallez, F. Touyeras, J.-Y. Hihn, Ultrason. Sonochem. 40 (2018) [5] J.Y.Hihn, F. Touyeras, ML. Doche, A. Mandroyan, C. Costa and B.G. Pollet in Power Ultrasound in Electrochemistry: From Versatile Tool to Engineering Solution, Chichester, UK, John Wiley & Sons Ltd 2012 [6] J.Y. Hihn, M.L. Doche, A Mandroyan, L. Hallez and B.G. Pollet in Handbook on Applications of Ultrasound: Sonochemistry for sustainibility, CRC Press Taylor & Francis in 2011 [7] B.G. Pollet, J.Y. Hihn, M.L. Doche, A. Mandroyan, J.P. Lorimer, T.J. Mason J. of Electrochem. Soc. 154(10) 131-138 2007 [8] L. Hallez, J. Lee, F. Touyeras, A. Nevers, M. Ashokkumar, J-Y Hihn, Ultrason. Sonochem. 29 194–197, 2016 [9] N. Sleiman, L Hallez, R Pflieger, SI Nikitenko, JY Hihn Ultrason Sonochem 83, 105939, 2022 [10] N. Sleiman, R. Pflieger, L. Hallez, S. Nikitenko, J-Y Hihn Ultrasonics Sonochemistry 104, 106836, 2024 [11] F. Lallemand., JY. Hihn, M. Atobe., A. Et Taouil. in Power Ultrasound in Electrochemistry: From Versatile Tool to Engineering Solution, Chichester, UK, John Wiley & Sons Ltd 2012