Water Absorption in Organic Coatings For Metal Substrate: A Review

Organic coatings are widely used for corrosion control of steel structures. The presence of moisture in the coating can activate corrosion process. For organic coatings to serve their intended purpose they must maintain a good adhesion with the substrate. Proper adhesion of the coating is related to the effective surface preparation. The surface preparation techniques for steel substrate include mechanical and chemical pretreatments. The surface characterization tests are carried out and roughness parameters are measured using surface profilometer. After surface preparation/characterization, organic coatings are applied to the substrate by different methods depending upon the purpose of application, types of coatings, size and geometry of the object to be coated, and site of application. The most commonly used techniques that have been applied to provide information on water uptake phenomena in coatings applied to substrate is electrochemical impedance spectroscopy (EIS) and Fourier Transform Infrared Spectroscopy (FTIR). EIS and FTIR determine the dielectric properties and structure of the material respectively.