Résumé : |
Metallic corrosion, or where iron and steel are concerned, rusting, is a phenomenon which occurs with most metals. Most metals are inherently unstable and, where circumstances permit, they will corrode to form a more stable material. The only exceptions are those metals which are found naturally as metals.
A metal such as iron is another matter entirely. It occurs naturally as an oxide (iron ore) and in order turn it into iron a lot of energy is needed. (Because of the high cost of energy a lot of scrap iron and steel is re-used nowadays). When it corrodes, iron or steel is merely becoming more stable and reverting to an oxide once again. |