Influence of sodium gluconate and cetyltrimethylammonium bromide on the corrosion behavior of duplex (α-β) brass in sulfuric acid solution

초록

The present research focuses on the corrosion inhibition of a two phases (α-β) brass in 0.5 M H 2 SO 4 solution containing sodium gluconate (SG) and cetyltrimethyl ammonium bromide (CTAB) at different temperatures. The inhibition effect was studied using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), Scanning Electron Microscope with Energy-Dispersive Spectrometer (SEM-EDS), Inductively Coupled Plasma Spectrometry (ICPS) and Density Functional Theory (DFT). Experimental results revealed that the corrosion inhibitors exerted a strong effect on brass corrosion and found to be less effective at a long immersion time (24 h). A concentration of 10 −3 M of SG in combination with 5 ppm CTAB (SG/CTAB) can cover up to 89% of the brass’ surface, which provides very good protection against corrosion, reducing the corrosion rate from 49 mA cm −2 to 5.5 mA cm −2 . The study also showed that the inhibition efficiency of SG/CTAB was slightly decreased at higher temperatures and their adsorption on brass surface was found to follow the Langmuir adsorption isotherm. The SG/CTAB acted as cathodic type corrosion inhibitors with insignificant changes in the anodic reaction. Electrochemical impedance spectroscopy (EIS) studies revealed that addition of 5 ppm CTAB to different concentrations of SG considerably increases the corrosion resistance of brass. The synergistic effect of SG and CTAB is also discussed. The SEM-EDS and ICPS analyses support the experimental results. Furthermore, quantum chemical calculations were used to understand the electronic properties of SG and CTAB. © 2019 Elsevier B.V.

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