Definition - What does Atmospheric Corrosion mean?
Atmospheric Corrosion refers to the reaction on the surface of a metallic object which deteriorates and degrades the metallic material and its vital properties. It occurs due to electrochemical as well as the other reactions which act on the exposed metallic surface with the constituents of the atmosphere surrounding the material. Corrosion alters the microstructure and drastically reduces the mechanical strength and useful life of the metals.
Petropedia explains Atmospheric Corrosion
There are many constituents in the atmosphere which can cause corrosion and erosion of metals and nonmetals if they are not protected. The presence of oxygen and condensed water vapor (moisture and humidity) in the atmosphere is sufficient to cause gradual corrosion of unprotected iron and steel surfaces, producing iron oxide, which is commonly known as rust.
The vital factor in our environment that contributes to atmospheric corrosion process is the presence of moisture due to fog, dew, precipitation and relative humidity. In a completely dry atmosphere, oxygen and carbon dioxide do not cause corrosion. Salts of sulfur and chlorine along with the other vital factors in the atmosphere can aggravate corrosion by forming electrolytes. Ambient temperature and air pressure also affect corrosion. At higher temperatures some electrolytes become highly reactive. The critical humidity which enables corrosion is a factor which is specific to each metal.