We expect to see rust on a vehicle or metal object that’s been left outside in the cold and damp. But we wouldn’t necessarily expect to see metal rust or corrode when it’s not outside in the harsh elements. We don’t really expect it even when its a metal object designed to contain or carry water, such as hot-water heaters or water pipes. However it does sometime happen, so what is the cause of it?
This is referred to as ‘galvanic corrosion’, what does this mean then?
Galvanic corrosion is caused when different types of metals that have been adhered to each other, even though they shouldn’t be, are exposed to something such as water, that can compromise their adherence. This would explain why pipes that should hold water without any problems, start to corrode or rust. A hot water heater could contain metal elements or metal insulation, but because the metal they are adhered to are dissimilar, when exposed to water they begin to rust and need to be replaced.
Maybe one of the most notable examples of galvanic corrosion is the Statue of Liberty. The wrought iron structure was joined with copper, and so when it was exposed to water, the greenish patina corrosion started to happen.
Is there a way to avoid galvanic corrosion in your home? We will address this in our next article.