Question

in what condition metals are corrode​

Answer 1

Corrosion is an electrochemical reaction that appears in several forms, such as chemical corrosion and atmospheric corrosion, the latter of which is the most common form. When acidic substances (including water) come in contact with metals, such as iron and/or steel, rust begins to form.

Answer 2

Any chemical process that negatively influence the properties of a structure would be called corrosion. It may be the result of chemical reactions with oxygen, sulphur, water, salt, … Rust is caused by oxidation of iron in the presence of water.