In metallurgy, stainless steel, also known as inox steel or inox from French "inoxydable", is defined as a steel alloy with a minimum of 10.5 or 11% chromium content by mass.
Stainless steel does not corrode, rust or stain with water as ordinary steel does, but despite the name it is not fully stain-proof. It is also called corrosion-resistant steel or CRES when the alloy type and grade are not detailed, particularly in the aviation industry. There are different grades and surface finishes of stainless steel to suit the environment the alloy must endure. Stainless steel is used where both the properties of steel and resistance to corrosion are required.
Stainless steel differs from carbon steel by the amount of chromium present. Unprotected carbon steel rusts readily when exposed to air and moisture. This iron oxide film (the rust) is active and accelerates corrosion by forming more iron oxide. Stainless steels contain sufficient chromium to form a passive film of chromium oxide, which prevents further surface corrosion and blocks corrosion from spreading into the metal's internal structure.
Passivation only occurs if the proportion of chromium is high enough.
Buenos Aires ( /ˈbweɪnəs ˈɛəriːz/ or /ˈaɪrɪs/, Spanish: [ˈbwenos ˈaiɾes]) is the capital and largest city of Argentina, and the second-largest metropolitan area in South America, after São Paulo. It is located on the western shore of the estuary of the Río de la Plata, on the southeastern coast of the South American continent. Greater Buenos Aires conurbation, which also includes several Buenos Aires Province districts, constitutes the third-largest conurbation in Latin America, with a population of around thirteen million.