Influence of barrier pigments on the performance of protective organic coatings

Powder and High-Solid Coatings as Anticorrosive Solutions for Marine and Offshore Applications? A Review

“…The two main groups of barrier pigments are mineral-based materials mineral-based materials (mica, micaceous iron oxide (MIO) and glass flakes) and metallic flakes (aluminum, zinc, stainless steel, nickel or cupronickel). For more information about the different types of barrier pigments please refer to [1,[18][19][20][21]].…”

“…Disbonding from damage is the result of bonds breaking at the coating-metal interface coming from the alkalinity of the cathodic products [1,4,19,63]. They are a result of electrochemical reactions occurring at the coating-steel interface, where solid iron is oxidized to ferrous ions and oxygen is reduced to hydroxyl ions at the metal-paint interface, see Figure 6 [64].…”

“…The extent of cathodic delamination, from a coating point of view, will be dependent of the ability of the interface to sustain an alkaline pH and the ability of the reactive species to diffuse through the coating and along the coating-substrate interface [19,20]. Other parameters, such as the potential of the coated steel (in case of cathodically protected steel), the type of electrolyte and its concentration, the oxygen concentration, the coating thickness will also influence the rate of cathodic delamination [1,4,68,69].…”

Three-Dimensional Structure Analysis and Percolation Properties of a Barrier Marine Coating

“…Barrier coatings, an essential branch of the corrosion-resistant coating family, are deliberately structured to operate in extremely aggressive environments such as seawater123 to prevent corrosion of substrate materials45. Among these coatings, the aluminium flake pigmented epoxy coatings are widely applied to protect steel structures such as ocean-going vessels because of their excellent anticorrosive performance1, as determined by their diffusion barrier properties2.…”

“…Among these coatings, the aluminium flake pigmented epoxy coatings are widely applied to protect steel structures such as ocean-going vessels because of their excellent anticorrosive performance1, as determined by their diffusion barrier properties2. The shape and spatial distribution of the aluminium flakes, usually several microns wide and a few hundred nanometres thick, added to the materials significantly improve the barrier properties by decreasing the transport rate of corrosive substances such as ions, water (vapour) and oxygen through coating films126. Additionally, the aluminium can react with the hydroxide ions produced at the cathode in the corrosion cell, reducing the pH at the coating-steel interface and decreasing the rate of cathodic disbondment7.…”