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NUMISMATIC VOCABULARY: POWDER METALLURGY
Paul Schultz came up with what sounds to me like a definitive answer to Ron Abler's question about how his centennial medal was made. Thanks!
-Editor
On that Centennial Medal that looks like it started with pellets of metal--it probably was. The process is called Powder Metallurgy, and is a fairly common but specialized metallurgical process. Here is the introduction from the article on that process as presented in Wikipedia, followed by the web link. The article is pretty good at explaining the whole process, so no need for me to re-type it.
"Powder metallurgy is the process of blending fine powdered materials, pressing them into a desired shape or form (compacting), and then heating the compressed material in a controlled atmosphere to bond the material (sintering). The powder metallurgy process generally consists of four basic steps: (1) powder manufacture, (2) powder blending,(3) compacting, (4) sintering. Compacting is generally performed at room temperature, and the elevated-temperature process of sintering is usually conducted at atmospheric pressure. Optional secondary processing often follows to obtain special properties or enhanced precision." It is possible that the medal was formed directly by a powder metallurgy process, or that the blank planchet was formed by powder metallurgy and then the planchet was struck in the normal way. Close examination would reveal the approach used. If you want a more detailed technical description, see: en.wikipedia.org/wiki/Powder_metallurgy
To read the earlier E-Sylum article, see:
QUERY: HOW WAS THIS CENTENNIAL EXHIBITION AWARD MEDAL MADE?
(www.coinbooks.org/esylum_v15n42a14.html)
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