Aerial Ultrasonic Wave Applications in Materials Processing

Aerial ultrasonic waves—high‐frequency acoustic vibrations propagating through air—have emerged as a versatile tool in a range of materials‐processing operations. By harnessing acoustic radiation pressure, cavitational microjets and high‐frequency oscillatory shear, these airborne waves enable non‐contact cleaning, de‐icing, surface texturing and enhanced powder handling without the need for liquid coupling. In cleaning and de‐icing applications, ultrasonic beams dislodge contaminants or ice by imposing rapid oscillatory stresses at material interfaces. In additive and subtractive processes, precise energy deposition permits controlled removal or deposition of material layers, while in powder spreading and granulation, ultrasonically induced agitation improves flowability and uniformity. Aerial ultrasound also underpins non‐destructive evaluation, where tightly focused beams reveal subsurface defects. The ability to deliver energy through air avoids many of the environmental and logistical drawbacks of liquid‐coupled ultrasonics. Recent advances in transducer design, beam‐forming and impedance‐matching materials have extended operational frequencies into the hundreds of kilohertz and beyond, achieving finer spatial resolution, higher acoustic power and improved directivity. These developments are fostering new routes towards sustainable manufacturing, enhanced safety in aerospace and infrastructure maintenance, and novel processing schemes in electronics, pharmaceuticals and composite materials.

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Aerial Ultrasonic Wave Applications in Materials Processing publication trend

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Technical terms

Aerial ultrasonic wave: A high‐frequency acoustic wave propagating through air rather than a liquid medium, employed for remote energy delivery.

Cavitation: The formation, growth and violent collapse of microscopic gas or vapour bubbles in a pressure field, producing localized high‐pressure jets and shock waves.

Acoustic radiation pressure: The steady force exerted on an object by a travelling or standing acoustic wave due to momentum transfer.

Air-coupled ultrasound: Ultrasonic energy transmitted and received through air, requiring specialised impedance‐matching transducers to overcome the large acoustic impedance mismatch between solid and gas.

Piezoelectric transducer: A device that converts electrical signals into mechanical vibrations (and vice versa) using piezoelectric materials, fundamental to generating ultrasonic waves.

References

1. Effect of Ultrasonic Vibration on the Surface Adhesive Characteristic of Iced Aluminum Alloy Plate. Applied Sciences (2022).
2. High-Frequency Ultrasonic Radiator Power Increase by Means of Summation of Vibrations of Symmetrically Arranged Langevin Transducers. Symmetry (2023).
3. Numerical and experimental analysis of focused air-coupled ultrasonic transducer based on cross-linked polypropylene film. AIP Advances (2022).