According to the different preparation process, the preparation methods of metal powder can be divided into reduction method, electrolysis method, grinding method, atomization method and so on. At present, argon atomization and plasma rotating electrode are commonly used in China.
1. Argon atomization
The powder by argon atomization is a method of powder making by using the rapid flow of argon to impact the metal liquid, breaking it into small particles, and then condensing it into solid powder.
2. Plasma rotating electrode method
Plasma state is called the fourth state of substance. The process of powder production by plasma rotary electrode atomization (PREP) can be described as follows: metal or alloy are made into consumable electrodes, and the end of consumable electrode melts into liquid film under the action of coaxial plasma arc heating source. The liquid film is dumped into droplets at high speed under the action of rotating centrifugal force. Molten liquid drops and inert gas in atomization chamber can be described as follows:(The friction of argon or helium) further breaks under the shear stress, and then the droplets cool and solidify rapidly to spherical powder under the action of surface tension.
The metal powder produced by plasma rotating electrode method has the following advantages:
The ball degree is high, the surface is smooth, the fluidity is good, and the loose density is high. Therefore, the powder spreading uniformity is good and the printing product is dense; the powder particle size is small, the particle size distribution is narrow, the oxygen content is low, the printing time is less / no spheroidization and agglomeration phenomenon, the melting effect is good, the surface finish of the product is high, and the consistency and uniformity of the printing can be fully guaranteed; there is no hollow powder or satellite basically In the process of printing, there will be no air gap, entrapment, precipitation porosity, crack and other defects caused by hollow ball.
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