Corrosion behaviour of organic composite coated steel sheet

Effects of resin types and their silica contents were studied on corrosion behaviour of organic composite coated steel sheets. The following results were obtained. (1) High corrosion resistance of organic composite coated steel sheets is brought by preservation of corrosion products on the coating. (2) Types of resin and contents of silica strongly affect the corrosion resistance by changing the kind of corrosion products developed on organic composite coatings. Coating with hydrophilic resin shows good resistance with protective ZnC12.4Zn(OH)2 formation. However, coating with hydrophobic resin forms ZnO which retards the corrosion resistance.