ИСТИНА

An effective way to reduce the corrosion hazard during the operation of underground structures is the use of polymer coatings and electrochemical protection. However, under actual operating conditions, the polymeric coating often detaches from the pipe, as a result of which the exposed portion of the metal surface contacts the ground electrolyte and the process of destruction of the metallic material begins. To prevent corrosion of the metal under the separated coating, it is advisable to add a corrosion inhibitor and adhesion promoters (organosilanes) to the primer layer (intermediate layer between the polymer coating and the metal). Organosilanes and corrosion inhibitors are actively used in the paint industry to enhance the anti-corrosion properties of paint coatings. One of the most studied heterocyclic inhibitors of metal corrosion is 1,2,3-benzotriazole (BTA). BTA has been shown to be able to effectively passivate iron and low carbon steel. In order to improve the adhesion strength of the coating, it is advisable to use, together with BTA, the adhesion promoters, which are organosilanes. In addition, it can be assumed that mixed inhibitory compositions based on organosilanes with BTA will make it possible to use them in paints coatings with aqueous and organic media. In this work, was studied the mechanism of formation of polymer-like protective films formed as a result of polycondensation of organosilicon compounds with inhibitors of the adsorption type, as well as the possibility of using compositions based on oranosilanes with benzotriazole as additives to water-borne and soluble paint coatings. It has been established that the addition of BTA compositions with silanes to aqueous chlorine-containing (borate buffer + 0.01 M NaCl pH 6.7) prevents the steel from dissolving and increases the potential of pitting formation by 0.4-0.5 V. Dense polymer-like forms are formed on the steel surface layers consisting of BTA molecules and silanes. Polymerization occurs due to the reactions of hydrolytic polycondensation of the molecules of organosilanes and BTA. Apparently, the main reason for the inhibition of iron dissolution is the decrease in the adsorption of aggressive chloride anions on the surface of a passive metal film due to the negative charge of the surface and the presence of dense crystal-like siloxane-azole nanolayer. For water-soluble coatings, the best results are obtained when using the inhibitor compositions of aminoethylaminopropyltrimethoxysilane (DAS) + BTA due to alkaline catalysis of hydrolytic polycondensation reactions and good solubility of DAS in aqueous solutions. For organo-soluble paints, the greatest effect is achieved when using the inhibitor composition BTA + vinyltrimethoxysilane (BC) because of the better compatibility of vinyltrimethoxysilane with the components of film-forming varnishes. The addition of silanes and BTA improves the physicomechanical properties of paintwork materials and their adhesion to metal.