The Atmospheric Corrosion Mechanism Of Carbon Steel And Inhibition Mechanism Of Volatile Corrosion Inhibitor Under Thin Electrolyte Layer

The atmospheric corrosion mechanism of carbon steel and corrosion inhibition mechanism of 2-Propynylamine under thin electrolyte layer were investigated through a self-designed experimental set-up. Potentiodynamic polarization curves, electrochemical impedance spectrum measurements(ESI), scanning electron microscopy(SEM), X-ray photoelectron spectroscopy(XPS) and attenuated total reflectance-Fourier transformed infrared(ATR-FTIR) were applied in this study.The effects of some factors such as temperature, relative humidity, chloride ion concentration, different exposure time and the content of CO2 in the atmosphere on the atmospheric corrosion behavior of carbon steel had been studied in this research. And the atmospheric corrosion of carbon steel showed regular changes. The atmospheric corrosion rate increases with the increase of temperature and chloride ion concentration, it also increases with the increase of relative humidity. When the relative humidity is up to 90%RH, the atmospheric corrosion rate changes little. The atmospheric corrosion rate decreases with the increase of exposure time. CO2 can accelerate the atmospheric corrosion because CO2 could dissolve in the electrolyte and when the content of CO2 is 8%, the atmospheric corrosion of carbon steel is most serious. When the content of CO2 are between 1% and 8%, the atmospheric corrosion rate increase with the increase of the content of CO2. When the content of CO2 exceede 8%, the corrosion rate reduce slightly.The initial inhibition effect of 2-propynylamine can be attributed to the adsorption of 2-propynylamine on the metal surface based on donor–acceptor interactions between the unshared pair electrons of the N heteroatom in the 2-propynylamine molecule and the vacant d-orbitals of surface iron atoms. 2-Propynylamine eventually undergoes polymerization reaction to generate a dense inhibition film. And it has good inhibition effect under different temperature. When the temperature is 55?, the inhibition effect is the best.