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| Effectiveness of Cathodic Protection under Simulated Disbonded Coating on Pipelines |
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| 中国科学院金属研究所 |
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Abstract The local potential and pH along a crevice simulating disbonded coating on pipelines were measured using microelectrodes.The effectiveness of cathodic protection (CP) in the local environment and the effects of applied cathodic potential, geometry of the crevice and solutio conductivity were investigated. The results showed that the IR drop in the disbondment mainly occurred in the vicinity of the opening. The distance effectively protected by CP increased with the decreasing applied potential. However, hydrogen evolution had a reverse effect when an overprotection potential was applied. The additional effct of CP was shown to be the modification of the local environment , such as increase of pH and conductivity of solution, which was beneficial to corrosion controlling as well as direct polarization of the exposed steel at the holiday.
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Received: 12 April 2006
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