Phosphate coatings as a way to protect steel reinforcement from corrosion

Phosphate coatings are successfully applied as a method of protecting steel products and structures from corrosion. Phosphate coatings mechanically prevent the entry of aggressive particles, such as chloride ions, to the surface of steel reinforcement. The parameters of corrosion rate of reinforcing steel in aggressive environment are determined by graphical method. The analysis of corrosion diagrams allows us to judge the effect of protective phosphate coatings on the kinetics of the corrosion process of steel reinforcement in environments of varying degrees of aggressiveness. The tests of the protective properties of phosphate coatings by contact corrosion method show that films with a finer crystal structure, as in modified phosphate coatings, are more resistant to anodic dissolution of steel. In parallel to determination of iron ions content in solutions the potential of steel reinforcement samples was measured. In samples protected by phosphate films, the potential change is not as sharp as in samples without coating, and the “dilution” of steel is slower. The study of anodic behavior of steel reinforcement of reinforced concrete, experimental study of the mass transfer mechanism of electrolyte supply to the surface of reinforced steel allow to develop practical recommendations to improve corrosion resistance and ensure the durability of reinforced concrete building materials.