Corrosion protection of reinforcement with phosphate coatings

Abstract

As a method of protection against corrosion, the application of phosphate coatings to the surface of steel reinforcement before the manufacture of a reinforced concrete product can be considered. The influence of modifiers introduced into the cold phosphating solution on the structure and protective properties of phosphate coatings was studied. It is established that from solutions with the addition of saccharin, glucose, Trilon A, Trilon B and washing preparations, fine crystalline, dense phosphate films are obtained. The introduction of the proposed additives also reduces the time of formation of a phosphate coating on the surface of the steel and leads to a decrease in their porosity. It has been established that phosphate coatings are resistant to the effects of aqueous, salt and acidic environments. Films deposited from modified cold phosphating solutions provide better corrosion protection compared to films obtained from a traditional cold phosphating solution. Presented phosphate coatings have high protective properties, because, due to their lower porosity, they well prevent the penetration of aggressive particles to the surface of the protected reinforcement.