Powder metallurgy (PM) is a metalworking process for forming near-net shape, precision metal components, and shapes from metal powders. One accepted definition describes powder metallurgy as the material processing technique used to consolidate particulate matter, both metals and/or nonmetals, into discrete shapes. Although the scope of this chapter is confined to metallic materials, the principles of the process apply to ceramics and other types of nonmetallic materials. There are four basic steps in the widely used conventional powder metallurgy process. These steps are powder manufacturing, blending, compacting, and sintering. For many applications, PM parts are ready for use after sintering. However, any one of several secondary operations can be performed to provide specific or special properties. Parts can be repressed, infiltrated, or impregnated. The controlled porosity of PM parts makes it possible to infiltrate them with another metal or impregnate them with oil or a resin to either improve mechanical properties or provide additional performance characteristics such as self-lubrication.