Cathodic delamination model

Fig. 24 Principal corrosion model explaining the formation of a galvanic element in case of cathodic delamination on polymer-coated iron, (a) Cross section through a metal-polymer interface with a defect in the polymer coating (b) overview of the polarization curves at the defect (i), the intact interface fii) and the situation after galvanic coupling of the parts (c).

Figure 7-59. Electrochemical model of cathodic delamination (Leng et al., 1999a).

From the preceding observations the model for cathodic delamination can be extended in the following way ... 

The model for anodic undermining shows large similarities to cathodic delamination. The main difference is the fact that oxygen transport through an open defect or... 

In more detail, the model of cathodic delamination can be described and understood as follows [3,57] the delamination starts with randomly distributed anodes and cathodes in a defect or at a dalaminated area. When iron is taken as an example, the dissolved Fe " at the anode is further oxidized to Fe + by oxygen and forms insoluble corrosion products in the defect that often adhere to the polymer (in the case of a blister) and at the edges of the defect (where oxygen enters the defect). In what way the defect is blocked and a cap of corrosion products is formed on the top of the blister see Figure 20.7. In this cap oxygen... 

In a recent review article written by and Amirudin and Thierry, different models of delamination on zinc-coated steel are discussed that range from purely cathodic to purely anodic [185]. Obviously, the... 

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