powder metallurgy

Powder Metallurgy

Powder Metallurgy (PM) is a metal forming process that utilizes fine particles of powder to shape components through pressure and heat. The powder used inPM consists of both metallic and non-metallic substances. Three basic steps are used in PM: powder production, component shaping, and sintering.

Powder Production

Powder production occurs in two methods, atomization and chemical precipitation. Atomization allows for powders of higher purity and consistent properties, but is more difficult with refractory alloys. Chemical precipitation is simpler and usually utilized for lower temperature alloys and ceramic compositions.

Component Shaping

Components are typically formed by pressing and compaction. Powders are either die formed or sinter bonded. Die forming using a tool and die set of the desired shape, which is then loaded into the press. Pressure and heat is applied to the component to achieve a rebound rate, or the bun height after being released from the die and then weighed. Compaction uses uni-axial pressing and allows for more complicated component shapes.

Sintering

Sintering is the process of bonding particles. A majority of the particles in the component remain as is, although during sintering, some particles may be altered in their size and shape. The temperature of sintering is usually lower than the melting temperature of the component alloys which allows for the component to be changed, yet remain intact and workable. This process does not however, produce a full, homogeneous component like regular solid forging.

Industry and Use

PM allows for components to be produced in a cost beneficial manner without sacrificing quality. After it has been used, recycled powder or new powder can be added and the component can be reshaped and sintered to produce a new component. PM is often used in the production of materials such as gears, bearings, magnetic cores, and structural components like aircraft parts.

Conclusion

Powder Metallurgy (PM) is a metal forming process which uses fine particles of powder to form components through pressure and heat. The powder used in PM consists of both metallic and non-metallic substances and the process consists of three basic steps; powder production, component shaping, and sintering. PM components have many uses in many different industries. PM also has the benefit of being cost effective and environmentally friendly, as it allows for components to be reshaped and reused multiple times.