Rust Layers in Steels Submitted to Dry-Wet Cycles

It is worth mentioning that at 0.6 M NaCI concentration for 46 days, the corrosion rate for CS and WS were of 3l00 xm per year and 3686 xm per year, respectively. For comparison purposes, it is possible to see that the performance of both steels in such aggressive environments of high chloride content is very poor, but it is even three to five times worse than in the case of total immersion tests. These corrosion rates seem to be inversely related to the iron conversion factor, which is lower (about 0.21) in the immersion tests than in the dry-wet tests (about 0.80). The different behaviors should be related to the type of iron phases, their characteristics, and their relative amounts. 

The values obtained for a were always less than one, suggesting that no protective rust layer was formed in these experiments, in agreement with the high corrosion velocities as reported above. The PAI values for CS range between 0.26 and 0.72, whereas those for WS range between 0.43 and 0.5. These values were always below I, which, compared to the high corrosion velocities well above 10 xm per year, are indicative of a nonprotective rust layer. On the other hand. 

Room temperature Mossbauer spectra of rust from carbon steel (a) and weathering steel (b) submitted to dry-wet cycles in 0.6 M NaCI concentration for 46 days. 

20 ENHANCING THE POSSIBILITIES OF MOSSBAUERSPECTROMETRY TO STUDYTHE INHERENT PROPEROES 

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