Powder Metallurgy(Metallic Powder)

Production of metallic powder

All the property of powder metallurgy only depends on the size of the powder of metal/alloy when it is produced. the important characteristic of powder includes the size, shape and size distribution.
 
There are the following number of processes a used to manufacture the metallic powder-

1. Solid-state reduction
2. Atomization 
3. Chemical and
4. Electrolysis 

Solid-state reduction 

• This process is generally used for the production of iron powder.
• In this process, the selected metal alloy is crushed, mixed with carbon and passed through a continuous furnace where a reaction place, which lives a cake of sponge metal. 
• This sponge-like metal is then Crush after separating from all non-metallic materials.
• Then it is sieved to produce the powder.
• The purity of the Powder depends on the purity of raw materials. The Powder particles are irregular and sponge-like which can be radially compressed to give good green strength. 

Atomization 

• In the atomization molten metal breaks into small droplets by rapidly freezing, before the droplets come into the contact with each other or with a solid surface. 
• The atomization is achieved by bringing the thing molten metal stream in contact with the impact of high-energy Jets of gas or liquid. 
• Air, nitrogen, and argon are commonly used gases, and water is the liquid most widely used. 
• In atomization, the particle shape is determined largely by the rate of solidification and varies from spherical, if a low-heat capacity gas is employed, to highly irregular if the water is used. 
• By wearing the design and configuration of Jet pressure and volume of the atomization fluid, the thickness of a string of stream of metal, etc. 
• it is possible to control the particle size distribution over the wide range.

Electrolysis

• In this process, the desired material is made as an anode in an electrolytic cell such that it is divisible by the electrolyte in the cell and then transported and deposited on the cathode in the sponge or powder form. 
• The deposit is removed, washed, and dried to get the metal powder. 
• Copper is the primary metal produced by electrolysis but iron, Chromium and Magnesium powder is produced using this process.