Interparticle Collisions Driven by Ultrasound

• Published in: Science (American Association for the Advancement of Science) Vol. 247; no. 4946; pp. 1067 - 1069
• Main Authors: Doktycz, Stephen J., Suslick, Kenneth S.
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for the Advancement of Science 02-03-1990; American Association for the Advancement of Science; The American Association for the Advancement of Science
• Subjects: 400201 - Chemical & Physicochemical Properties; Acoustics; Applied sciences; Chemical Phenomena; CHEMICAL REACTIONS; Chemistry; Comets; DATA; Exact sciences and technology; EXPERIMENTAL DATA; FLUID FLOW; FLUIDS; INFORMATION; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; Irradiation; LIQUIDS; Melting; Metal particles; Metal powders; Metals; Metals. Metallurgy; Microscopy, Electron, Scanning; Microspheres; Minor planets; NUMERICAL DATA; Particle collisions; Powder metallurgy. Composite materials; Production techniques; Scanning electron microscopes; SHOCK WAVES; Slurries; Solid-liquid equilibrium; SOLIDS; SOUND WAVES; Transition metal compounds; TURBULENT FLOW; ULTRASONIC WAVES; Ultrasonics; Ultrasonography; Scanning electron microscopy; Melting; Interparticle interaction; Metal powder; Tin; Irradiation; Iron; Experimental study; Particle collision; Ultrasound; Velocity; Zinc
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.2309118

Ultrasound has become an important synthetic tool in liquid-solid chemical reactions, but the origins of the observed enhancements remained unknown. The effects of high-intensity ultrasound on solid-liquid slurries were examined. Turbulent flow and shock waves produced by acoustic cavitation were found to drive metal particles together at sufficiently high velocities to induce melting upon collision. A series of transitionmetal powders were used to probe the maximum temperatures and speeds reached during such interparticle collisions. Metal particles that were irradiated in hydrocarbon liquids with ultrasound underwent collisions at roughly half the speed of sound and generated localized effective temperatures between 2600°C and 3400°C at the point of impact for particles with an average diameter of ∼10 μm.