what is the benefits of atmospheric corrosion
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Answer:
10.1 INTRODUCTION
Atmospheric corrosion is the degradation of materials caused by air and the pollutants contained in the air. It can be precisely defined as an electrochemical process which depends upon the presence of electrolyte which may be rain, dew, humidity or melting snow. The usual electrolyte is water which is a universal solvent. Atmospheric corrosion takes place under humid conditions, where the atmospheric relative humidity exceeds the equilibrium relative humidity over any saturated solution which is present on the metal surface (usually NaCl solution, which is ubiquitous).
K=∑tntnVk(n)
where K = accumulated corrosion productstn= time constant Vk= average corrosion rate during the period of wetness.
The corrosion rate is controlled by time of wetness, temperature and the electrolyte composition. Atmospheric corrosion is most predominant of all the other forms of corrosion. The importance of atmospheric corrosion is exemplified by the fact that the cost of protection against atmospheric corrosion is about 50% of the total cost of all other corrosion measures. No other form of corrosion affects the materials and equipment harder than atmospheric corrosion. Its devastating range extends from small articles, such as bolts, nuts and fasteners to industrial plants and equipment and megastructures, such as skyscrapers, towers and bridges. Atmospheric corrosion has not only its own share of engineering catastrophes, such as collapse of concrete structure and bridges, which occur from time to time, but also affects the public utilities and military combat readiness. It is, therefore, important for engineers to understand the relation between the material and the environment to incorporate control measures in the design.