How Are Stainless Steel Outdoor Lights Anti-Corrosive?

Why is a stainless steel garden light "stainless"?
The resistance to corrosion to stainless steel in garden lights arises from a "passive", chromium-rich, oxide film forming naturally to the surface of the metal steel used in the manufacture of garden lights. At only 1-5 nanometres (i.e. 1-5 x 10-9 metres) thick this thin film is protective enough to strongly adhere, it is chemically stable (i.e. passive) under conditions which provide sufficient oxygen to the surface of the garden lights. A key element to a stainless steel garden light's durability of the corrosion resistance is that should the oxide film become damaged it will self repair, provided sufficient oxygen is available. Contrast to other steels types that yield to common corrosion where areas of the surface are affected, stainless steel used in garden lighting are in the passive state and therefore resistant to this form of attack.
Corrosion and oxidation resistance of stainless steel in Urban garden lights
The corrosion/oxidation resistance within stainless steel garden lights will improve as the chromium content increases. Additions of nickel to create the austenitic stainless steel grades will strengthen the oxide film to raises performance of stainless steel in certain conditions. Addition of molybdenum to either the ferritic or austenitic stainless steel garden lights improves pitting corrosion resistance.
What is stainless steel used in Urban garden lights?
Stainless steel garden lights contain chromium, or a combination of chromium and nickel, as well as amounts of other alloy additions, typically molybdenum will used in the manufacture of stainless steel. Chromium content of a stainless steel garden lights is generally greater than 14 per cent, it is this alloy that will keep the garden light's steel rust resistant and bright in spite of moisture or the action of corrosive acids and gases in the air. The presence of nickel will further improve corrosion resistance of stainless steel garden lights as does molybdenum.
Different grades and types of stainless steel.
Key requirement for use of stainless steel in outdoor garden lighting is that it should be corrosion resistant for the specified application and the environment the garden lighting will be fitted in. The final selection of a particular grade and type of stainless steel used in the manufacturing of garden lighting must initially meet the corrosion resistance requirements. It is worth noting that various grades of stainless steel will be used for the manufacture of stainless steel outdoor garden lighting. A garden light produced for warmer less damp climate could be manufactured using a lower and less expensive grade of stainless steel. For application in a damp and cold climate the correct grade of stainless steel must be used for garden lighting. A cheap alternative means of using lower grade stainless steel for budget outdoor garden lighting is to coat the surface with clear lacquer, this will last a year or two but eventually the lacquer will peel and discolour the garden lights.
All Urban garden lights are manufactured using high grade stainless steel for total protection against the elements.