This work is to development of the corrosion resistance of the steel pipeline structures utilizing concrete coating by using the cathodic protection technique to protect the structure of the coated steel pipeline structure. It deals with the matter of steel structures upon the survey periods, electrochemical dormant period because of the continuous cathodic presentation and the activation corrosion upon interruption period of this cathodic presentation and treatment this case of corrosion by using the cathodic protection technique. The initial free corrosion potential (Ecorr) upon intermittently intervals and corrosion rate measurement of the specimens by using full polarization curve (Tafel method) has been observed.
The results indicate that the moisture progressive within each specimen has produced different potentials along the steelpipe. Greater polarization has been associated with the submerged part of the specimen where the concrete coating resistance is at minimum. Whereas the degree of polarization is directly proportional with the level of external voltage. The results indicated that to achieve efficient design of a cathodic protection, the protected area should be divided into discrete electrochemical areas depending on the electrical resistance and steel potential to prevent the over-protection in the low electrical resistance areas. Furthermore, the results indicate that the absolute value of protection potential does not adequately to describe the electrochemical changes undergone by the polarized coated steelpipe. Owing to the flowing current between anode and cathode, the voltage drop is mainly not proportional with the electrical resistance of isolated coating, only when the coating is uniform over the entire area of steelpipe.
تاريخ النشر
29/03/2007
الناشر
The 10th Annual conference of the Foundation of Technical Education
د.عبدالوهاب حسن خضر | Dr. Abdulwahab Hassan Khuder | 4547