3. Powder Metallurgy
Powder Metallurgy is an art & Science of Producing Powders and using them to make
finished or semi finished products
The Powders Could be
Metallic (Iron, Copper, Aluminum, Tin, Nickel etc……)
Non Metallic (Silica, Alumina, Calcia, Magnesia,
Silicon Carbide, Silicon Nitride, Boron Carbide etc…..)
5. Powder Production
Common Methods of Powder Production are
Atomization
Comminution
Electrolytic Deposition
Reduction of Metal Oxides
Mechanical Alloying
6. Atomization
This uses high pressure fluid jets to break
up a molten metal stream into very fine
droplets, which then solidify into fine
particles
7. Types of Atomization
Water atomization
Gas atomization
Centrifugal atomization
Ultrasonic atomization
11. Reduction of Metal Oxides
Process use gases as a reducing agent (Hydrogen and Carbon monoxide)
Also known as the removal of oxygen
Very fine metallic oxides are reduced to the metallic state
Spongy and porous powders are produced
12. Mechanical Alloying
Powders of two or more pure metals are mixed in a ball mill
under the impact of hard balls the powders fracture and bond together by
diffusion ,forming alloy powders
The dispersed phase can result in strengthening of the particles or can impart
special electrical or magnetic properties
13. Pressing
1) Filling of Powder in Die Cavity
2) Initial Position of Punches
3) Final Position of Punches
4) Ejection of Compact
14. Cold Isostatic Pressing
Mold made of elastomer (Neoprene,
rubber, urethane)
Pressurized at 200MPa to 400MPa in
aqueous medium (Oil /Water)
15. Powder Rolling
This process involves feeding of
powders between rolls to produce a
coherent and brittle green strip. This
green strip is then sintered & re-rolled
to obtain a dense, finished product.
16. Sintering
7 Sintering is thermal treatment of a powder or compact below the melting
temperature of the main constituent for increasing its strength by bonding
together of the particles.
