Quote:
Originally Posted by svandamme
pretty sure its oxydation not corrosion
if it were corrosion the statue would have been gone by now.
oxidation = protective layer. which makes it durable in time
normal copper corrosion is insignificant it is considred a noble metal
to actually corrode copper, there would have to be some ammonia, salt, sulfar or acids involved.
I doubt acid rain is enough
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The statue of liberty is corroded, and the green color is, I believe, not a direct result of oxidation, but oxidation is a part of the process. -
https://www.corrosionpedia.com/definition/1258/oxidized-copper
"Oxidized copper is a specific type of corrosion that is produced during a three-step process where copper oxidizes to copper oxide, then to cuprous or cupric sulfide, and finally to copper carbonate. It results in a green-colored copper layer or patina that forms over time.
Oxidation is one form of metallic corrosion, which is a reaction that occurs during an ionic chemical reaction when oxygen is present on the metal’s surface. During this process, electrons move from the metal to the oxygen molecules. Thereafter there is a generation of negative oxygen ions in the metal, thus leading to the creation of a surface laden with oxide. In the case of copper, this oxidation occurs as a result of the exposure of copper to air, although salt water, acidic compounds and heat can also induce corrosion.
Corrosion of most metals can cause serious damage and become a dangerous hazard if it affects infrastructure objects such as buildings, sewage pipes, ships and water supply pipes. However, copper corrosion is not as destructive because the copper forms a protective outer oxide layer that discourages further corrosion."
Corrosion can cause a protective layer. -
https://www.sciencedirect.com/topics/engineering/corrosion "I.C Passivity - Some metals, notably the stainless steels, titanium, aluminum, and chromium, corrode to form a thin film of corrosion product on their surfaces that greatly protects them from further attack. Carbon steels form a passive film that is only partially protective and is easily damaged."
Oxidation which is a type of corrosion can be a cause for the protective layer.
