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The measured densities of powders – both, the apparent density and the tap density – are low compared to the wrought metals because of the gaps between the particles. They vary in a wide range between 0.5 and 6 g/cm3 depending on the morphology of the particles and their tendency to agglomeration. Precious metal powders can be compacted by pressing and then sintered; a certain amount of porosity is however always retained.
<figure id="fig:Different shapes of silver powders"> Fig. 8.1: Different shapes of silver powders a) spherical b) rounded crystal applomerates
[[File:Different shapes of silver powders.jpg|right|thumb|Different shapes of silver powders a) spherical b) rounded crystal applomerates]]
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Precious metal powders are produced by various methods, such as for example electrolysis, atomizing from the molten phase, chemical precipitation,
or by cementation with non-precious metals. Depending on the manufacturing process silver powders – as the by far largest volume precious metal powder used – have 2 bilder Fig. 8.1: Different shapes of silver powders a) spherical b) rounded crystal applomerates different properties as shown in <xr id="tab:DifferentTypesofSilverPowders" /> (Tab. 8.1) and (Tab. 2.12). Atomizing from a melt results in a powder with high tap density composed of spherical particles. Using electrolytic deposition from a silver salt solution creates randomly shaped dentritic to crystalline particle structures. Chemical processes can result in rather fine particles with a large specific surface area. <xr id="fig:Different shapes of silver powders"/> Fig. 8.1 shows typical SEM photo-graphs of atomized silver powder in spherical shapes (a) and a cementation powder composed of rounded crystal agglomerates (b).