Oxygenates rural atmospheres

The protection afforded in rural atmospheres is greater than that in urban or industrial atmospheres. In the latter area there is a greater concentration of industrial pollutants. The air in these areas is contaminated with various sulfur compounds, which together with the moisture in the air convert the normally impervious corrosion-resistant zinc carbonate and zinc oxide layer into zinc sulfate and zinc sulfite. These water-soluble compounds have poor adhesion to the zinc surface and therefore are washed away relatively easily by rain. This exposes the underlying surface to attack by oxygen in the air. 

A rural atmosphere is normally classified as one that does not contain chemical pollutants but does contain organic and inorganic dusts. Its principal corrodents are moisture and, of course, oxygen and carbon dioxide. Arid or tropical atmospheres are special cases of the rural environment because of their extreme relative humidities and condensations (Ref 4). Hie rural atmosphere is generally the least corrosive. 

Atmospheric corrosion results from a metal s ambient-temperature reaction, with the earth s atmosphere as the corrosive environment. Atmospheric corrosion is electrochemical in nature, but differs from corrosion in aqueous solutions in that the electrochemical reactions occur imder veiy thin layers of electrolyte on the metal surface. This influences the amount of oxygen present on the metal smface, since diffusion of oxygen from the atmosphere/electrolyte solution interface to the solution/metal interface is rapid. Atmospheric corrosion rates of metals are strongly influenced by moisture, temperature and presence of contaminants (e.g., NaCl, SO2,. ..). Hence, significantly different resistances to atmospheric corrosion are observed depending on the geographical location, whether rural, urban or marine. 

Oxygen and air. Titanium alloys are totally resistant to all forms of atmospheric corrosion regardless of pollutants present in either marine, rural, or industrial locations. Titanium has excellent resis-... 

The Influence of Oxygenates on the Atmospheric Chemistry of Urban, Rural, and Global Environments... 

---