The use of organosilanes to inhibit metal corrosion. A review

A review of scientific and technical literature on the development of methods for the deposition of organosilicon coatings by modifying metal surfaces with organosilanes before applying an anti-corrosion polymer or paint coating is presented. The review covers scientific and technical information concerning the achievements in the deposition of organosilicon nanolayers on various metal surfaces and their characterization by modern research methods. The choice of organosilanes capable of creating siloxane surface layers that significantly increase the anticorrosive efficiency of a polymer/paint coating, i.e. providing both efficient corrosion protection and high adhesion of the polymer coating to the metal, is considered and justified. The processes that occur upon hydrolysis of organosilanes in aqueous solutions and upon interaction of silanes with a metal surface are considered. The main theories that describe the finishing action of organosilanes at a metal-polymer interface and the hypotheses that explain the mechanism of the formation of metal-siloxane bonds with the surface are presented. The mechanism of the anticorrosive action of siloxane surface layers is considered. The application of surface layers formed on a metal by modification with aqueous solutions of environmentally safe organosilanes for replacement of conversion coatings obtained by surface treatment with toxic hexavalent chromium compounds is discussed. It is shown that corrosion inhibitors are added to modifying aqueous organosilane compounds in order to enhance the anticorrosive efficiency of coatings and to provide the “self-healing” effect. Information on the synergistic effect of mixtures of organosilanes with corrosion inhibitors is provided and the mechanism of synergistic action of the mixtures is discussed.