During this process, the solid metal material is reduced to individual particles, or powder, through one of many processes. Metal powder can be made from many different materials, including aluminum, copper, bronze, nickel, brass, steel, stainless steel, nickel and titanium.
Metal powder is the starting product for the process of powder metallurgy in which solid metal products are fabricated. Metals such as aluminum, copper, bronze, nickel, crass, steel, stainless steel, titanium and more are all commonly used to make metal powder. In addition, alloy powders can be created from a combination of these elemental materials.
There are a number of methods by which powdered metal can be created, some of the most common of which include atomization, chemical precipitation, centrifugal disintegration and hydrogen reduction. Atomization, the most frequently used method, separates molten, or liquid, metal into tiny separate beads which are then frozen into a solid form of powder. Centrifugal disintegration uses a rotating electrode and metal rod within a chamber. The resulting force melts droplets off the metal which solidify and form a powder.
Grinding and chemical reactions are also commonly used to formulate a metal powder from a solid metal piece. Once a metal has been deconstructed into powder form, it is then able to be used to fabricate products through the process of powder metallurgy. Widely used in applications such as automobile components, structural parts, filtration systems and magnetic assemblies, metal powder and powder metallurgical construction are important elements of manufacturing.
Powder metallurgy, for which metal powder is required, has many advantages as a fabrication method. It is a simple method that consists of mixing the metal powder, compacting it into a die and then sintering, or heating, the die to form a solid shape. The powder is melted, fusing it together and causing it to bond in the shape of the die. The result is a solid metal part, also know as a sintered metal part. Powder metallurgy, or PM, is a cost effective fabrication process as it results in minimal waste. Other types of metal fabrication processes result in products that need a lot of secondary finishing, or result in lots of scrap metal pieces.
Powder metallurgy however uses the metal powders conservatively and the pieces do not require excessive finishing. The process is able to achieve close finish tolerances with both simple and complex shape requirements. Natural finishes on most metals are also suitable and therefore extra heating and finishing is not often required. If solid metal parts do undergo further heat treatment, this will add to their strength and level of wear resistance. High purity powders should be used for the best results in terms of metal density and smooth finish.