Powder metallurgy sintering

Powder metallurgy (sintering) is the process whereby powdered iron or other metals are combined together at high pressure without high heat to fit molded forms. This process is used to produce homogenous (uniform throughout) metal parts. 

Foams can be fabricated by dissolution in acid, anode oxidation in liquid, or simply using powder-metallurgy sintering with or without placeholder or scaffolds [35-37]. For example, nanoporous gold is made by the dissolution in acid of silver atoms from an Au/Ag alloy during dissolution, gold atoms in the lattice of the... 

Herring C 1949 Surface tension as a motivation for sintering The Physics of Powder Metallurgy ed W E Kingston (New York McGraw-Hiii) pp 143-79... 

Post-Sintering Treatments. The sintering process concludes the powder metallurgy processes of production and consoHdation. However, some P/M parts may require a number of further operations. 

Nuclear Applications. Powder metallurgy is used in the fabrication of fuel elements as well as control, shielding, moderator, and other components of nuclear-power reactors (63) (see Nuclearreactors). The materials for fuel, moderator, and control parts of a reactor are thermodynamically unstable if heated to melting temperatures. These same materials are stable under P/M process conditions. It is possible, for example, to incorporate uranium or ceramic compounds in a metallic matrix, or to produce parts that are similar in the size and shape desired without effecting drastic changes in either the stmcture or surface conditions. OnlyHttle post-sintering treatment is necessary. 

In powder metallurgy, the powdered material to be worked is pressed in a mold, then heated to increase the rate of diffusion. The temperature required to obtain flow of the material may be significantly below the melting point. As the powder becomes more dense and less porous, the vacancies move to the surface to produce a structure that is even less porous and more dense. In addition to diffusion, plastic flow and evaporation and condensation may contribute to the sintering process. As sintering of a solid occurs, it is... 

Molybdenum is malleable and ductile, but because of its relatively high melting point, it is usually formed into shapes by using powder metallurgy and sintering techniques. 

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