How does rust work to eat away a metal?

Question

Where does rust come from? How does it begin to form and why only on certain metals?

In: Chemistry

Answer 1

Rust is the combination of a metal with oxygen, for example let’s say you have an iron pipe that’s not painted or covered in any way, oxygen in the air will combine with the iron and form iron oxide which we usually know as rust, if there’s nothing interacting with the pipe rust will form a layer on the surface and that’s it, the problem is rust is brittle so if something rubs against it the rust will chip away revealing fresh iron that will again combine with more oxygen, repeat this process for long enough and you end with a hole on the pipe.