Synthesis of thin organic layers containing silane coupling agents and azole on the surface of mild steel. Synergism of inhibitors for corrosion protection of underground pipelines

Abstract

The mechanism of steel inhibition by 1,2,3-benzotriazole (BTA) formulations with organosilanes was studied by electrochemical methods and X-ray photoelectron spectroscopy (XPS). It was shown that the simultaneous introduction of these inhibitors into chloride-containing neutral media significantly reduces the rate of uniform and pitting steel corrosion. The use of scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) made it possible to investigate the distribution of elements in inhibitory formulations of 1,2,3-benzotriazole with organosilanes under various conditions for modification of steel surface. High efficiency of inhibitor compositions is associated with the formation of "polymer-like" protective layers as a result of silanes hydrolysis followed by hydrolytic polycondesation with BTA molecules. It was determined that these species in defined ratios create synergistic compositions with high inhibiting efficiency. The synthesized layers to decrease the adsorption of aggressive chloride anions due to possible negative surface charging and the presence of dense crystal-like siloxane-azole layers tightly bound to metal. The compositions are planned to use in adhesive layers for polymeric tapes used for protection of underground pipelines.