Ultrasonic systems are applied in numerous industries – their cost-efficiency, effectiveness and eco-friendliness are the vital aspects giving the technology a massive popularity boost. Mentioned below are the most common spheres of ultrasonic use according to Hilsonic, one of the leading ultrasonic cleaner manufacturers in the UK and the company deeply involved in ultrasound technologies development.
The impact of sonication on melt significantly increases the intensity of the formation of bubbles of dissolved gas, and as a result, its content can be reduced by two times or even more, even if sonication is not prolonged. The occurrence of gas bubbles in the melt is followed by flotation of scattered hard nonmetallic inclusions, which increases the density of the casting and melt flowability, enabling to penetrate into the smallest recesses of the mold. Further degassing, there is a significant decrease in the grain, which results in further improvement of physico-mechanical properties of the casting. Melt treatment is usually performed immediately before casting and may be carried out both in a stationary volume of the furnace or mixing bucket using a submersible radiator with a working tool of refractory materials, and by ‘scoring’ the metal in the channel by means of a special tray or using a multi-layer filter screen of glass that provide, besides ultrasonic degassing, filtering the melt. The technology is applicable to a low-density low-melting metals and their alloys.
Intensification of galvanic and chemical processes
Under the influence of ultrasonic processes on copper plating, nickel plating, chrome plating, cadmium plating, zinc plating, silver plating and a number of other materials a reduced polarisation and hydrogen ion discharge is facilitated, thus providing an increased cathodic current density, accelerating the deposition of coatings. In fact, ultrasound increases the active area of the cathode by 3 times. As a result a more uniform coating of the required thickness is achieved, improving its adhesion to the substrate. The technology is implemented through the connection of submerged ultrasonic emitters with frontal type of radiation.
Today catalysts are the most common element of chemical technology. But few know that the similarities, the specific effects can be achieved with the help of powerful ultrasonic waves. Moreover, ultrasound is capable of intensifying the many physical and physico-chemical processes which do not affect the catalysts. Structurally related settings are made in the form of a fixed volume (e.g. ultrasonic bath) or in the form of systems with immersion transducers.
Preparation of emulsions and suspensions
Under the influence of the ultrasound on the mixture of mutually insoluble liquids a transition of one liquid dispersed in another condition in the medium – emulsification (ultrasonic dispersing liquid in the liquid) takes place. Resistance emulsion obtained by ultrasound is significantly higher than in other types of resistance systems. The technology is implemented with the help of ultrasonic baths and ultrasonic units with submersible transducers for large volumes of production are used installation flow.
The process is based on sonocapillary effect and used for impregnating electrical products: the transformer windings, rotors, stator coils etc., as well as for sealing porous molded parts. As a result, the impregnation time is reduced by several times, and in some cases, a single impregnation instead of multiple is achieved.