Application of ultrasonic wave in metal powder preparation

　As an important industrial raw material, metal powder is increasingly used in electronics, metallurgy, energy, and aerospace. With the modern industry, the performance requirements of the particle size, purity and morphology of metal powder materials are gradually improved, although the preparation methods of traditional metal powders such as water atomization, gas atomization and centrifugal atomization have entered large-scale industries. In the production stage, but due to the process characteristics of the powder characteristics such as particle size, particle size distribution, powder geometry, etc., it is difficult to meet the requirements of high-performance metal powder in some areas. In order to meet the needs of this new situation, metal powder ultrasonic atomization technology has undoubtedly become a hot core research topic in the ultrasound industry today.
　First, the status quo of metal powder preparation technology:
　From the practical point of view, in many metal powder preparation processes, the atomization method is the most important preparation method of solder powder. According to different atomization methods, there are mainly three kinds of gas atomization, rotary disk centrifugal atomization and ultrasonic vibration atomization.
　1. Gas atomization: gas atomization is to use a high-speed gas stream to crush and atomize the molten liquid flowing through the nozzle into fine droplets, and to cool and solidify in the sedimentation to form powder particles. It is characterized by high milling efficiency and large yield, but the products obtained are mostly ellipsoidal and have coarse surface with fine powder adhesion, high oxygen content, wide particle size distribution, high proportion of fine powder, and difficult processing in subsequent processes. . In addition, nitrogen consumption is large and the cost is high.
　2, rotating disk centrifugal atomization method: rotating disk centrifugal atomization was originally developed by the American Prattz & Whitney aircraft manufacturing company. Due to its unique powder size, controllability and cleanliness of the shape and low cost, it has been paid more and more attention, and has become an important method for preparing metal or alloy powder. Compared with gas atomization, the preparation of solder powder by centrifugal atomization method makes the control atmosphere relatively easy, the product has good sphericity, small oxidation degree, easy particle size control, high yield and large output. The disadvantage is high equipment speed, high heat resistance and wear resistance of the motor. In addition, the use of vacuum exhausters and high speed motors has increased the cost of the equipment.
　3. Ultrasonic atomization method: Ultrasonic atomization method is a new type of milling method developed in recent years. The molten metal is atomized into powder by ultrasonic waves. Compared with the above two atomization processes, the solder powder prepared by the ultrasonic atomization process has the best sphericity, a narrow particle size distribution, and a low oxygen content, but the yield is small.
　Second, the new metal powder ultrasonic atomization technology has the following advantages compared with other atomization methods:
　1. The prepared powder has the advantages of high purity, low oxygen content, good sphericity and uniform particle size distribution.
　2. The equipment and process are simple, the operation is convenient, and the product quality is stable and controllable.
　3. Significant advantages such as low energy consumption, high utilization rate and low cost.
　4. Ultrasonic atomization method has obvious characteristics such as environmental protection, energy saving, low carbon and sanitation.
　Practice has proved that the metal powder ultrasonic atomization technology is a new energy-saving and environmentally-friendly metal powder preparation technology. If it can be reasonably applied, it will have broad application prospects in the modern industrial field.