Metal and oxygen in the atmosphere in the oxidefilm formed on the surface. In continuation ofiron oxide is formed on oxidation of ordinarycarbon steel, corrosion continued to expand,eventually forming holes. You can use paint oroxidation of metal (for example, zinc, chromiumand nickel) plating to ensure the surface ofcarbon steel, but as you know it, thisprotection is only a film. If the protective layer is damaged, the following steel begins torust.
Corrosion resistance of stainless steel hosedepends on chromium content, when chromium isadded to 10. 5%, significantly increasedresistance to atmospheric corrosion of steel,but higher chromium content, although you maystill increase corrosion resistance, but notobvious. Because when alloyed with chromium onsteel, changed into similar to the type of surface oxide formed on the surface of purechromium metal oxides. This tight adhesion ofchromium-rich oxide surface, preventing furtheroxidation. This kind of very thin oxide layer,through which you can see the natural shine of the stainless steel surface, stainless steel hasa unique surface. And if the damaged surface,exposed steel surfaces and the atmosphericresponse to repair itself, forms the"passivation", continues to play a protectiverole.