Improving the Anticorrosion Characteristics of Polymer Coatings in the Case of Their Modification with Compositions Based on Organosilanes

Abstract

Abstract The effect of a series of organosilanes and their mixtures with corrosion inhibitors on the anticorrosion properties of polymer and paint coatings on steel, namely, on the adhesive characteristics of the coatings and corrosion behavior of the metal in the presence of coatings modified with organosilanes, corrosion inhibitors, and their mixtures, is studied. It is shown that mixtures of 1,2,3-benzotriazole (BTA) with vinyltrimethoxysilane (VTMS) or aminoethylaminopropyltrimethoxysilane—diaminosilane (DAS) inhibit the local dissolution and underfilm corrosion of carbon steel, and the potential of local depassivation shifts by 0.3–0.4 V. Here, compact polymer-like layers that are strongly bound to the metal surface are formed on the surface of steel. Corrosion and mechanical tests of the samples of pipe steels with different types of inhibiting compositions are conducted. The effect of the inhibitors on the crack growth under static loading in a model soil electrolyte (pH of 5.5) and on the crack resistance of steel under slow tension in an NS-4 model underfilm electrolyte (pH of 7.0) is evaluated. The tests are performed in media free from and containing hydrogen sulfide. It is shown that the best inhibiting properties are manifested by the mixtures of corrosion inhibitors with organosilanes. Comparative laboratory and bench tests for the adhesive strength, water resistance, and resistance to cathodic detachment of the adhesive junctions obtained upon applying the modified polymer and paint coatings onto the surface of steel are performed. It is found that introducing a mixture of organosilane and a corrosion inhibitor improves the adhesive properties of polymer and paint coatings.