Why use a glass flake coating?
Glass flakes have a high aspect ratio, which is low thickness to surface area. In a coating, the flakes overlap each other and by forming a tortuous path, present a barrier to the diffusion of liquids and gases. Particles of a granular or spherical nature do not overlap and offer only limited resistance to diffusion through a coating.
In terms of the benefits of using glass flakes these are many, in addition to the primary function as a barrier pigment. This is due to the control over flake thickness and particle size diameter, giving large aspect ratio platelets. In addition to the properties listed above glass flakes may also reduce lateral shrinkage during cure and give a compound thermal expansion similar to carbon steel.
This allows the coating to retain good adhesion even under thermal shock, have improved abrasion resistance and better dimensional stability. Glass flake coatings have a proven track record of providing long term protection, in some cases up to 25 years service.