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Powder metallurgy can be described as a metal processing technology employed to produce fine metal powders that are blended and then pressed to get the desired shape and followed by sintering process to bond the particles of the metal into a rigid mass. Metallic powders are elemental particles that are usually less than 1000 nm (1 mm) in size. Most of the metal particles used in PM are in the range of 5 to 200 mm. History of powder metallurgy dates back to 1000 AD where the ancient Arabs and Germans made high quality swords from iron powder . Powder Metallurgy is a sequential process of producing powder metallurgical materials, comprising manufacturing of powder, blending, sintering and pressing. One of the most important characteristics of this process is the shaping of metallic objects from powdered materials without melting .
This process is used to obtain intricate and near net shapes components that are extensively employed in areas requiring high precision, prominent being automotive, aerospace and medical fields. Iron, copper and aluminium are the most commonly used elemental powdered materials in this process. It is easy to fabricate any shape of a metal by powder metallurgy which are difficult to be shaped by any other methods and can be automated for economical production. Different alloys are mixed with powdered materials to get the definite shape and size of the product, some combinations of alloys manufactured by powder metallurgy cannot be produced in any other ways. The material wastage is very minimal, and the unusual mixtures of various materials can be utilized. The parts are made up of specific level of porosity in which the porous metal parts are produced. Furthermore, powder metallurgy route is green manufacturing and energy efficient manufacturing compared to casting and other metallurgical operation .
Powder metallurgy process can also be employed in manufacturing and processing of non-metal powders to products, which exhibit metallic properties, such as iron oxide based magnetic materials, ferrites, sintered corundum for machining and forming etc. In practice, the PM technology can be successfully applied to a manufacture of components from all typical metal materials. This also enables to make components of very complicated shapes, reducing the necessity of final machining which saves material as well as energy. In many cases properties of a material manufactured using the PM technology surpasses an adequate material made with the use of a different technology. Many unique products can be manufactured with powder metallurgy technology such as tungsten light bulb filaments, Automotive brake linings, spacecraft heat shields for re-entry into earth’s atmosphere. Future scope of powder metallurgy is vast, especially in the areas of Carbon nanotubes (CNTs) in which reinforced magnesium nanocomposites were synthesised using the powder metallurgy technique followed by hot extrusion process . Powder metallurgy technique is being developed a lot due to its industrial significance and immense research work is being done to increase productivity and ease in manufacturing.