This has two main reasons:
(1) saving costs compared to alternative processes, or
(2) special attributes attainable by the PM-route only.
Saving costs plays a significant role within the following uses:
Structural (or mechanical) Parts:
This is the undoubted larger group.
Parts on iron base are the main section, but significant amounts of aluminium, brass, bronze and copper parts are produced as well as some titanium and beryllium. Although such parts have advantage over forgings in dimensional accuracy the main reason for their use is the economic thought. Within the past few years it has become possible to produce sintered parts, like with Hot Isostatic Pressing Services / Heißisostatisches Pressen with properties equal to or even superior to those of parts made in more traditional ways. There have been developments as well as in the materials as in modifications in the whole standard process of production.
Concerning parts with special characteristics the following examples shall be given:
Porous Materials: Most forms of metal are porous to some extent, sintered metals, poduced with a Hot isostatc Press (HIP) or also in some cases with a Cold Isostatic Press (CIP) even more, but here we have a process of producing parts having a significant adjusted porosity for several required purposes. The main products of this group are filters and oil-retaining bearings also referred to as self-lubricating bearings.
The following products cannot be produced satisfactorily by alternative processes:
Refractory metals have extremely high melting points such as molybdenum, tungsten, niobium, tantalum and rhenium. They are very difficult to produce by melting and casting plus are very brittle during cast state. A sintered powder compact can be deformed at a suitably elevated temperature mechanically. Then it gradually develops a microstructure with preferred orientation that gives the meanwhile dense material useful elasticity even at ambient temperatures.