Powder metallurgy is a metalworking process for forming precision metal components from metal powders by compacting in a die.
Process Details:
The following are the basic steps of powder metallurgy:
Power production: Numerous processes can produce metallic powders: grinding, electrodeposition, comminution, atomization, chemical reduction, etc. In atomization, a liquid metal stream produced by injecting molten metal through a small orifice and the steam is broken up by jets of inert gas, air or water. The powder is also produced by reduction of metal oxides using hydrogen or carbon monoxide, as reducing agents. Mechanical comminution involves crushing, milling in a ball mill or grinding brittle or less ductile metals into small particles.
Powder Mixing: The process of mixing includes mixing of various metal powders are thoroughly intermingled. This is carried out in batch mixers. The temperature during mixing affects the friction between powder particles. With increasing temperature, the friction coefficient between most materials increases and the flow of powders is impaired.
Compacting: A controlled amount of the mixed powder is introduced into a precision die, and then it is pressed or compacted at room temperature and pressure in the range 100 Mpa to 1000 Mpa. In doing so, the loose powder is consolidated and densified into a shaped model. The model is called green compact. As it comes out of the die, the compact has the size and shape of the finished product. The strength of the compact is just sufficient for in-process handling and transportation to the sintering furnace.
Sintering: Sintering involves heating of the green compact in a protective atmosphere furnace to a suitable temperature below the melting point of the metal. Typical sintering atmospheres are endothermic gas, exothermic gas, dissociated ammonia, hydrogen, and nitrogen. Sintering is responsible for producing physical and mechanical properties by developing a metallurgical bond among the powder particles. It also serves to remove the lubricant from the powder, prevents oxidation, and controls carbon content in part.
To know More about Powder Metallurgy grab the chance and attend the forthcoming Conference: 5th International Conference on Advanced Material Research and Nanotechnology.
Dates of the Conference: May 22-23, 2019
Venue: Rome, Italy
For more Details: Advanced Materials 2019
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