Authors: K. Hielscher
Affilation: Hielscher Ultrasonics, Germany
Pages: 232 - 242
Keywords: ultrasonic production of nano particles, synthesis, milling, deagglomeration, dispersion
The application of mechanical stress – e.g. generated by ultrasonic cavitation - breaks the particle agglomerates apart. Also, liquid is pressed between the particles. Different technologies are commonly used for the dispersing of powders into liquids. This includes high pressure homogenizers, agitator bead mills, impinging jet mills and rotor-stator-mixers. High intensity ultrasonication is an interesting alternative to these technologies and particularly for the particle treatment in the nano-size range the only effectual method to achieve the required results. Intense cavitational forces allow for dispersing and milling of particles, e.g. pigments down to nano-size. Ultrasonic milling and dispersing narrows the particle size distribution curve significantly and avoids the “right tailing”. Thus, particle characteristics and product’s quality are greatly enhanced. The present paper discusses the advantages of ultrasonic milling and dispersing and shows the advantages of this innovative technique compared with traditional methods. By ultrasonication, the most important parameters – amplitude, pressure, temperature, viscosity, and concentration – can be fully controlled. Thereby, every specific process can be optimized and scaled-up linearly from bench-top up to production size.