Metal powder
A metal powder is a fine powder of a metal that usually burns very well, while a solid piece of the metal cannot or only with difficulty burn. Metal powders are usually obtained by grinding (mechanically). But they can also be obtained chemically, physically or by electrolytic means. By decomposing metal carbonyls into metal and carbon monoxide , very pure and fine metal powders can be obtained. Carbonyl iron is obtained from the decomposition of iron pentacarbonyl . Similarly, nickel - and manganese powders are produced.
Examples of common metal powders:
Manufacturing
The production of metal powders can be broken down as follows:
- Mechanical processes (grinding in a mill or atomizing molten metal)
- Physical processes (evaporation of the metal and subsequent condensation, atomization of the metal in an arc)
- Chemical processes (reduction processes, carbonyl processes)
- Electrolytic processes (in an electrolytic bath, the metal is deposited as a powder on the cathode)
use
Metal powders are used, among other things, in the production of metal ceramics ( powder metallurgy ). They serve as the base material and are pressed into the desired workpiece shape. During the subsequent firing ( sintering ) of the so-called green body , the molded part solidifies through diffusion processes at the contact points of the metal powder particles. Another method is selective laser sintering ( Selective Laser Sintering ), a rapid prototyping process for the rapid production of models from CAD data, while the sintering process takes place directly in the powder bed instead.
Magnetic particle clutches and magnetic particle brakes use magnetizable (steel) powder for the frictional transmission of torque.