Is Copper-aluminum the same alloy as Aluminum-bronze?
WillieBoyd2
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Sometimes I see coin metals listed as "Copper-aluminum" or "Aluminum-bronze", sometimes for the same coin.
The old 1960's Yeoman world coin catalogs used "Aluminum-bronze" while the Numista website (https://en.numista.com/catalogue/index.php) uses both terms.
For example:
Argentina 10 Centavos 1943 (19.0 mm, 3.0 gm)
Yeoman: Aluminum-bronze
Numista: Aluminum-bronze (https://en.numista.com/3248)
France 1 Franc 1940 (23.0 mm, 4.0 gm)
Yeoman: Aluminum-bronze
Numista: Copper-aluminum (https://en.numista.com/707)
These alloys run around 89 to 95 percent copper and the rest is aluminum.
Sometimes small amounts of other metals are added.
My guess is that "Copper-aluminum" is the more modern term as the metal with the higher percentage is listed first.
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"Aluminium bronze" would be defined as any alloy with copper as the #1 element and aluminium as #2. As you note, perhaps other elements are present, perhaps not. For example, Australian coinage aluminium bronze is 92% copper, 6% aluminium, 2% nickel.
"Aluminium brass", which you might see elsewhere, would be an alloy with a significant zinc component, and usually a lower copper component, but with aluminium as either #2 or #3.
The Wikipedia article for "aluminium bronze" currently has a 5 franc coin from 1940 as an illustration of the alloy. https://en.wikipedia.org/wiki/Aluminium_bronze Curiously, Numista calls that 5 franc coin "aluminium bronze" as well, despite the 5 franc and 1 franc coins certainly being made from exactly the same alloy. Numista is a French website and these modern French coins would have been part of the original core of the database, so I "checked it in the original language", and curiously, the French versions of the two coin entries also use different terminology, despite both giving the alloy as 91.0% Cu, 9.0% Al.
1 franc: "Cupro-aluminium" - https://fr.numista.com/707
5 francs: "Bronze-aluminium" - https://fr.numista.com/1189
The English-language entries for these two coins are simply direct translations of these two different phrases. So I suspect the disparity is simply a "wiki effect" - two different people editing different parts of the wiki, and using two different terms to describe the exact same substance.
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