1181Reducing the Aggressiveness of the Environment

Changes to the environment may be brought about to alter the factors that affect corrosion rate, namely temperature, pH, oxygen concentration, humidity, concentration of active species, presence of dissolved solids, and pollutants, for the case where the environment is predominantly gaseous, that is atmospheric corrosion. The aggressiveness of the environment may be reduced by lowering the temperature, lowering the relative humidity, and eliminating aggressive species such as chloride, sulfur, and nitrogen oxides and carbon dioxide. Also conditions should not be such that temperature differentials exist between surfaces such that dew point or condensation corrosion can be initiated.

With aqueous environments corrosion rates may be reduced by lowering the temperature, conductivity, and oxygen concentration. In addition, but dependent upon the nature of the metal/alloy, a change in the pH of the solution can reduce corrosion rate through the formation of passive films.

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