Copper and materials made of copper alloy oxidize when exposed to the atmosphere, causing its shiny surface to tarnish. You know that any water can induce corrosion, but here are factors that can make corrosion happen even more quickly: Saltwater. Heat.

What causes copper to oxidize?

Similarly, when exposed to the atmosphere, copper will oxidize due to a reaction with oxygen and liquid water or moisture in the air. The characteristic red outer layer (rust) that forms when iron corrodes is caused by oxidation. ... Oxidation adds a blue-green color to copper, brass and bronze.

What is the oxidation of copper?

The oxidation number of metallic copper is zero. In its compounds, the most common oxidation number of Cu is +2.