Glass flake reinforced epoxy coatings have been widely used for many years on substrates exposed to extremely aggressive environments (such as splash zones of offshore installations). Glass flakes with high aspect ratio (large surface area and low thickness) can be dispersed in the epoxy resin and increase the path length for the diffusion of moisture and chemical ions. Therefore, it is believed that glass flake additives are particularly useful for harsh environments. In addition, glass flake additives are also known to enhance the durability of coatings. In this article, we used different analytical tools to determine the influence of glass flake quantity on the anti-corrosive properties of an epoxy coatings reinforced with glass flake.
Environments in oil and gas industries are often characterized by high temperature and pressure, harsh chemicals, humidity, extreme stress cycles, radiation, and mechanical disturbances.1,2 These extreme conditions degrade the ability of materials to perform, thus requiring enhanced protection through application of heavy-duty anti-corrosive and chemical resistant coatings that can withstand the aggressive environment.3
Organic coatings, because of their relatively low cost and excellent barrier protection, are typically the most viable option for protecting harsh environment assets. However, even superior quality organic coatings in their pristine form allow diffusion of chemical ions, moisture, or gas to some extent as a part of their inherent nature, resulting in coating degradation.4 A common method to improve the performance of harsh environment organic coatings is by reinforcing the polymer matrix with fillers.5 The enhanced corrosion protection may be derived from either a mechanical barrier from precipitation of inert salts or electrochemical protection through galvanic or passivation mechanisms.
Glass flake is one such filler that has been used in coating industries for several years to improve the performance of epoxy coatings in highly corrosive environments.6 Previous research have demonstrated that the incorporation of glass flakes into organic coatings increases the resistance of the coating to chemical ions as well as moisture or gas diffusion. Glass flake particles that have high aspect ratio (large surface area and low thickness) can align themselves in the polymer matrix parallel to the substrate. This creates a more torturous pathway for the permeation of the aggressive ingredients that come in contact with the coatings and results in extension of the coating lifetime.7-8 In addition to reducing permeability of the coating system, many glass flakes can offer additional advantages compared to other fillers. They provide abrasion resistance, mechanical hardness, and chemical inertness and do not impart additional color into the coating. This often makes glass flake a preferred filler choice for use in development of coatings for extreme environments.