Corrosion of metals
2013-1-21 · Why do metals corrode? Apart from gold, platinum and a few others, metals do not occur in the nature in their pure form. They are normally chemically bound to other substances in ores, such as sulphides, oxides, etc. Energy must be expended (e.g. in a blast furnace) to extract the metals from the sulphides, oxides, etc to obtain pure metals.