Characterization of metal-metal oxide/polymer coatings on various material surfaces and measurement of corrosion rate by electroanalytical methods

Corrosion is a phenomenon that occurs as a result of electrochemical and chemical interactions between a metal material and its surroundings. Every material made of metal is affected by corrosion, which can lead to significant economic losses. To reduce the rate of corrosion in a metal material, a film can be formed on the metal surface, or the metal can be coated using various methods. In this thesis study, coatings were applied to the surfaces of 304L and 316L austenitic stainless steel types using metal/metal oxide (Sn/SnOx, Zr/ZrOx, Ti/TiOx, Te/TeOx) and various organic substances (phenolphthalein, taurine, pyrogallol red, etc.) with the aim of reducing the corrosion rate. Electrochemical metal-metal, metal-organic substance, and dual organic substance coatings were studied on steel samples individually and in binary mixtures. The methods used included cyclic voltammetry from electrochemical techniques, the sol-gel method from solution-based processes, and the sputter method from gas-based processes to coat the steel surfaces. The results of the materials obtained using these coating methods were compared with each other, and the effect of the methods on the corrosion rate was investigated. The corrosion rate of bare and modified steel surfaces was calculated as mm/year using the Tafel extrapolation method. Additionally, the polarization resistance values occurring on the steel surface were compared. Nyquist plots were obtained for the steel materials using Electrochemical Impedance Spectroscopy (EIS). The steel material surfaces were characterized using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) techniques. As a result, modifications of titanium, zirconium, and selenium-based substances and some dyes on steel, both alone and in combination with metals, were investigated. It was observed that these modifications on the steel surface significantly reduced the corrosion rate compared to bare steel. These coatings will enable the materials to be used for a longer period.