In this work, a test rig was developed to study the effect of cathodic protection (CP) on corrosion of X70 pipeline steel in the crevice area under disbonded coating through the measurements of local potential, solution pH and dissolved oxygen concentration. Results demonstrated that, in the early stage of corrosion of steel, CP cannot reach the crevice bottom to protect steel from corrosion due to the geometrical limitation. Corrosion of steel occurs preferentially inside crevice due to a separation of anodic and cathodic reaction with the depletion of dissolved oxygen in the crevice solution. The main role of CP in mitigation of sequential corrosion of steel in crevice under disbonded coating is to enhance the local solution alkalinity. With the increase of distance from the open holiday, a high cathodic polarization is required to achieve appropriate CP level at crevice bottom. A potential difference always exists between the open holiday area and inside crevice, reducing the CP effectiveness.


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    Title :

    Effect of cathodic protection on corrosion of pipeline steel under disbonded coating (Short Communication)


    Additional title:

    Einfluss von Kathodenschutz auf die Korrosion von Rohrstahl unter einer enthafteten Beschichtung (Kurzmitteilung)


    Contributors:
    Chen, X. (author) / Li, X.G. (author) / Du, C.W. (author) / Cheng, V. (author)

    Published in:

    Corrosion Science ; 51 , 9 ; 2242-2245


    Publication date :

    2009


    Size :

    4 Seiten, 3 Bilder, 23 Quellen




    Type of media :

    Article (Journal)


    Type of material :

    Print


    Language :

    English