Principle of Ultrasonic Metal Powder Production
The ultrasonic metal powder equipment directly inputs the liquid to be atomized onto the surface of the tool head of the ultrasonic transducer, forming a thin liquid layer. The thin liquid layer generates surface tension waves under the action of ultrasonic vibration. When the amplitude of the liquid droplets on the surface of the liquid exceeds that of the tool head, the droplets will fly out and be atomized into small droplets. During the atomization process, the thickness of the thin liquid layer has a significant impact on the atomization effect, which limits the mass flow rate of the liquid to be atomized and restricts the increase in atomization rate.
The following figure shows the tin powder prepared by ultrasonic mist.
Ultrasonic atomization is a new type of atomization technology that transfers the energy of ultrasonic waves to the liquid to be atomized and crushes it by directly contacting the ultrasonic tool head. This powder making technology can obtain spherical metal powders with good sphericity and narrow particle size distribution, while also having significant advantages such as simple equipment and process, high controllability, and low cost.
The process parameters that control powder characteristics (size, distribution, shape, and oxygen content) are related to atomizer design (nozzle geometry), atomizer operating conditions (fluid properties, pressure, temperature, atmosphere), and materials (melting temperature, viscosity, surface tension, superheat). Some of these parameters have a significant impact on the characteristics of the powder. For example, low metal viscosity, low metal surface tension, high metal superheat (the temperature difference between the molten metal and its melting temperature), small nozzle diameter, high atomization pressure, and large flow rate are beneficial for producing fine powder.
Metal alloy atomization was developed to meet the needs of metallurgical science. As a strictly controllable atomization method with process parameters, the development of ultrasonic atomization technology is of great significance in the production of metal powders with controllable particle size, good sphericity, and high purity, especially in the preparation of high-performance spherical metal powders with particle size less than 20 μ m.
