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Influence of hot water conditioning on the corrosion behavior of carbon steel
Author(s) -
Banica C.E.,
Czempik E.,
Vogt C.,
Schneider F.
Publication year - 2002
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/1521-4176(200204)53:4<256::aid-maco256>3.0.co;2-k
Subject(s) - corrosion , dielectric spectroscopy , materials science , carbon steel , metallurgy , conditioning , passivation , scanning electron microscope , anaerobic corrosion , electrochemistry , composite material , chemistry , electrode , layer (electronics) , statistics , mathematics
The effect of hot water conditioning on the corrosion behavior of carbon steel in aqueous solutions of sodium chloride has been examined. In particularly, it has been examined the effect of water conditioning in the presence of octadecylamine = ODA on the corrosion and passivation of carbon steel, which was a major point in this research because of the big interest in the improvement of the hot water corrosion situation in electric and heating power stations of development countries, where a lot of damage is produced on the walls of the heat exchangers. It has been tried to determine which conditioning methods are working to improve the corrosion resistance and also to remove the deposits. Because it is known that ODA = Octadecylamine improves the corrosion resistance (it does not allow the formation of thick layers and also removes the deposits), it has been tried to develop a method of hot water conditioning by using ODA. For examining the corrosion behavior and the resistance of these materials electrochemical techniques have been used: DC – Potentiodynamic scanning AC – Electrochemical Impedance Spectroscopy (EIS) Scanning Electron Microscopy (SEM) was applied to determine the morphology of the oxide layers. Additionally, the electrolytes after hot water conditioning were analyzed for dissolved iron. The most important results are: 1. Hydrazine conditioning reveals in pure hot water much lower corrosion than oxygen conditioning. 2. ODA addition retards the corrosion much more in the case of hydrazine conditioning, than in the case of oxygen conditioning. 3. Hot water conditioning in the case of carbon steel does not form protective oxide layers resistant to 0.01 m Cl − ‐solution (low polarization resistance, no passive range). 4. ODA showed no beneficial effect on the anodic branch of the polarization curve in 0.01 m Cl − ‐solution, but it reduced the cathodic currents.