Sonochemistry (4) The Evolution of Ultrasound Continues (Production of Nanoparticles)
Ultrasound is used to generate countless vacuum balls (cavities) of 10 mm in diameter in water. 20,000 times per second or more, these vacuum balls are generated and annihilated in 1/40,000th of a second. At that time, positive and negative shock waves are generated. In water, a vacuum ball of 10 mm in diameter is repeatedly generated and annihilated at ultrahigh speed.
This is ultrasonic waves.
Metals, minerals, and various other fine powders captured inside the shock wave are pulverized by the strong pressure change, and finally sub-micron particles are generated. Up to this point, it is easy. If the fine powder in this state is further subjected to more powerful shock waves that generate cavities that dissipate at higher speeds, nanoparticles are produced. Although the details are still to be revealed, ultrasonic waves can be effectively used to produce nanoparticles without relying on chemical reactions or reduction reactions.
by shibano