Guo Xingpeng

Corrosion inhibition mechanism of carbon steel by sodium N,N‐diethyl dithiocarbamate in hydrochloric acid solution

The effect of sodium N,N‐diethyl dithiocarbamate (SDEDTC) on the corrosion of carbon steel in 0.5mol/L hydrochloric acid (HCl) solution was studied using weight loss, potentiodynamic polarisation curves and impedance measurement methods. Experimental results revealed that SDEDTC acted as an inhibitor in acid environments. Moreover, the compound was a mixed‐type inhibitor, acting predominantly as a cathodic inhibitor. Inhibition efficiency increased with increasing SDEDTC concentration at different temperatures. The corrosion inhibition mechanism of SDEDTC for carbon steel in HCl solution was also investigated by impedance techniques.

Inhibition of Ethyleneamine on the Pitting Corrosion of Rebar in a Synthetic Carbonated Concrete Pore Solution

Tetraethylenepentamine (TEPA) was surveyed to show strong inhibition on pitting corrosion of Q345B carbon steel in a carbonated synthetic pore solution (SPS) by electrochemical noise (ECN), electrochemical impedance spectroscopy (EIS), and polarization curves. The pitting corrosion potential shifts positively with an increase in the TEPA concentration. ECN data show that the low content of TEPA can increase the nucleation rate of the metastable pits slightly and can effectively reduce their lifespan. The high content (0.10 mol·L - 1 ) of TEPA accelerates the repassivation of metastable pitting and this is accompanied by an increase in noise resistance and a decrease in the nucleation rate and average pitting charge until the noise current transients disappear completely. Both the baseline current and the amplitude of the current transients decrease with an increase in the TEPA concentration, indicating that TEPA retards not only the pitting corrosion but also the general dissolution of the passive film. Micrographs show that the metastable pits mainly initiate and develop around the stable pits because of the induction of corrosion products, which causes the pitting cavity on carbon steel to grow generally in a planar rather than in a perpendicular direction.

Inhibition performance and adsorption behaviour of dodecylamine on N80 steel in CO2‐saturated brine solution

Purpose – This paper seeks to investigate the different inhibition performance and adsorption behaviour of dodecylamine in acidic and neutral environments and to understand further the inhibition mechanism of dodecylamine in CO2‐saturated brine solution.Design/methodology/approach – The inhibition performance and adsorption behaviour of dodecylamine on N80 steel in CO2‐saturated brine solution in acidic and neutral environments were investigated by potentiodynamic polarization, electrochemical impedance spectroscopy and the attenuated total reflection‐Fourier transform infrared spectroscopy.Findings – Corrosion potentials exhibited a pronounced shift in the positive direction at higher concentrations of dodecylamine. The inhibition efficiency of dodecylamine was shown to be pH‐dependent. The effective inhibition concentration of dodecylamine decreased from pH 4.9 to 7.4. In a neutral environment, the inhibitor was shown to affect the deposition of the corrosion products and provide more active sites to bo...