Depending on its chemical composition, steel changes its properties very strongly. If it contains more than 12% chromium, it is coated with a chromium oxide layer only a few atoms thick, which protects it from corrosion. An example of such stainless steel is cutlery. By immersing stainless steel in saline solutions, the salt eats wholes into the protective layer. This can happen, for example, when too much salt is used in the dishwasher.