Cathodic delamination of seawater-immersed anticorrosive coatings: Mapping of parameters affecting the rate

Sörensen, Paul; Dam‐Johansen, Kim; Weinell, Claus Erik; Kiil, Søren

doi:10.1016/j.porgcoat.2010.03.012

Cited by 69 publications

(46 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is generally believed that in coating-metal systems hydrogen or secondary bonds between the metal oxide layer and the polymer (e.g. polar groups) are dominant [1,3]. Adhesion can, for example, be improved by using coupling agents.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, we used a model system with different layer structures to differentiate between those possibilities (see chapter 2.2). The transport of dissolved oxygen and water is generally considered to be sufficient to sustain corrosive reactions and therefore not to be the rate determining process (see [1][2][3] and references). For example, the cathodic delamination of epoxy coatings was found to be most probably controlled by the interfacial transport of hydrated cations in a thin aqueous layer at the coating-steel interface [2].…”

Section: Introductionmentioning

confidence: 99%

“…In that case, the transport of cations is considered to be the rate determining process, therefore, a proportionality between mean diffusion length, x , and diffusion time, t , has been assumed [3]:…”

Section: Introductionmentioning

confidence: 99%

“…app D is an apparent diffusion coefficient, taking into account that the transport of the ions is facilitated by an electrical field gradient [2,3] between anode and cathode resulting from the cathodic reaction [17]. This behaviour can be expressed using the Nernst-Planck equation.…”

Section: Introductionmentioning

confidence: 99%

“…The various methods having been used to examine deteriorating coating performance comprise classical methods like the 'cross cut adhesion test' or visual methods (e.g. removal of delaminated coating, measuring the rusted area underneath [3,8]). More advanced methods, based on electrical potential, electrical impedance or acoustic properties of the coating are Scanning Kelvin Probe (SKP) [25 -27], Electrochemical Impedance Spectroscopy (EIS) [6,27,28] and Scanning Acoustic Microscopy (SAM) [25,26,29], respectively.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Investigation of delamination mechanisms in polymer coatings by scanning acoustic microscopy

Alig¹,

Bargmann²,

Oehler³

et al. 2010

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

Scanning acoustic microscopy (SAM) was used to investigate disbonding, delamination and blister formation in polymer coatings for different layer structures and initial defect depths during exposure to a corrosive environment. The time evolution of disbonding and blister initiation and their growth was investigated by analysing the SAM images exposure to an electrolyte solution (Harrison solution). From investigations of a model system of coatings on steel substrates, it was possible to differentiate between water and/or ion transport (i) through the coating and (ii) along the coating-steel interface. For samples without clear coat randomly distributed blisters appeared at the coating-steel interface after exposure to the electrolyte solution, irrespective of the location of initial defects. The random distribution of growing blisters is related to diffusion of water and/or ions through the coating and "nucleation" at weak points of the substrate or within the polymer. For samples with clear coat a propagating migration front along the coating-steel interface of 3-4 µm height -starting from initial defects -was detected. The linear propagation of this front cannot be explained by Fickian diffusion. Therefore, it is discussed in terms of an accelerated diffusion or crack growth kinetics. Since blistering starts only at sites, where the migration front has passed, the presence of a thin water layer at the coating-steel interface, the loss of adhesion and the following corrosive processes are prerequisites for the nucleation of blisters. The blister growth shows a square-root time dependence which was related to a diffusion controlled transport mechanism.

show abstract

Section: Introductionmentioning

confidence: 99%