The powder metallurgy process is bound to involve the preparation of powder. The powder preparation process can be divided into three main categories, one is the rapid solidification atomization powder technology, the other is the mechanical alloy powder technology, and the other is It is an ultrafine powder preparation technology.
The rapid solidification atomization powder milling technology of powder metallurgy is relatively straightforward. This type of powder milling technology can effectively reduce the segregation of alloy components, so the obtained alloy powder components are relatively uniform.
Due to the different atomization media used, the atomization methods used in powder metallurgy powder technology also have a variety of choices, such as two-stream atomization, gas atomization, high-pressure water atomization, centrifugal atomization, vacuum atomization, etc. In two-stream atomization, after the atomizing medium and the metal liquid flow are sprayed through the nozzle, the two liquid flows collide with each other, thereby breaking the liquid flow and spraying powder.
In the gas atomization method, the gas pressure generally reaches 2-8 MPa, and the powder particles with smooth surface can be obtained on this basis for powder metallurgy. The water atomization method uses water with a higher density as the atomization medium, so the condensation rate achieved is an order of magnitude higher than that of the general gas atomization method, so the shape of the obtained powder is generally irregular.
Mechanical alloying powder milling technology is a way to prepare alloy powder or composite powder from element powder. It is completed in a high-energy ball mill and requires long-term grinding between powder particles and between powder particles and grinding balls. The powder will be broken and torn. The ultrafine powder preparation technology in powder metallurgy has significantly different physical, chemical and mechanical properties due to the small particle size.