Corrosion rate behavior during different

Fig. 1 -28 shows the corrosion behavior of non-alloyed steel under rural, urban, and industrial environmental conditions (Barton 1973). This example can be used to discuss different trends. In the aggressive industrial atmosphere linear corrosion at a rate of 0.05 mm year" was reached after exposure for 1.5 years. During the first 18 months the corrosion rate was greater. In the urban atmosphere linearity was measured after 3 years the corrosion rate was low, 0.015 mm year". ... 

The foregoing description is of necessity oversimplified. For one thing, one is always dealing with an alloy rather than the pure metal, as pointed out earlier. During corrosion, the components of the alloy do not, as a rule, dissolve at a rate that is proportional to their respective concentrations. The medium in which the sample is corroding may also be complex, containing, for example, several different anions. All this leads to the formation of many simultaneous hydrolysis equilibria. Nevertheless, a detailed analysis can be made, at least in principle, for any specific case of interest, and the observed behavior can be interpreted in terms of the phenomena just discussed. ... 

---