22 Aug Piezo Ceramics – At the Core of Ultrasonic Liquid Processing

Exposed Piezoelectric Ceramics in Ultrasonic Transducer

Ultrasonic homogenizers are powerful tools used in the laboratory and industrial settings to break down and disperse materials. At the core of an ultrasonic homogenizer is a piezoelectric ceramic, which is responsible for generating the high-frequency vibrations necessary for the homogenization process. In this article, we will explore how piezoelectric ceramics work and their role in producing vibrations in an ultrasonic homogenizer.

Piezoelectric ceramics are a type of material that can convert electrical energy into mechanical energy and vice versa. When an electric field is applied to a piezoelectric ceramic, it deforms, producing mechanical stress. Conversely, when mechanical stress is applied to the ceramic, it generates an electric field. This phenomenon is known as the piezoelectric effect.

In an ultrasonic homogenizer, a piezoelectric ceramic is used to produce high-frequency vibrations. The ceramic is typically composed of lead zirconate titanate (PZT), a material that exhibits a strong piezoelectric effect. The ceramic is cut into a specific shape, such as a disk or ring, and electrodes are attached to its surfaces. When an alternating current is applied to the electrodes, the ceramic expands and contracts, vibrating at high frequencies.

The frequency of the vibrations produced by the piezoelectric ceramic determines the size of the cavitation bubbles that form in the liquid being homogenized. Cavitation is the formation and collapse of small bubbles in a liquid. When the ceramic vibrates, it creates pressure waves that travel through the liquid, causing it to vibrate and form cavitation bubbles. As the bubbles collapse, they generate high pressures and temperatures, resulting in the fragmentation of particles and the dispersion of materials.

The efficiency of an ultrasonic homogenizer depends on the strength and stability of the vibrations produced by the piezoelectric ceramic. The strength of the vibrations is affected by several factors, including the size and shape of the ceramic, the thickness of the electrodes, and the frequency of the alternating current applied to the ceramic. Additionally, the stability of the vibrations can be affected by the temperature and the quality of the electrical connections between the ceramic and the power source.

In conclusion, piezoelectric ceramics are critical components of ultrasonic homogenizers, responsible for generating the high-frequency vibrations necessary for the homogenization process. The piezoelectric effect allows these ceramics to convert electrical energy into mechanical energy, producing vibrations that cause cavitation bubbles in the liquid being homogenized. Understanding how piezoelectric ceramics work and their role in ultrasonic homogenization is essential for optimizing the efficiency of these powerful tools in the laboratory and industrial settings.

-Joshua Detzel, ChBE