Abstract
The acidic corrosion of carbon steel is a great concern, which has caused serious economic losses on a global scale. Therefore, the exploitation of corrosion inhibition strategy for carbon steel and an in-depth study on its mechanism are of vital importance. Here we have developed a mixed type corrosion inhibitor of PPy-CTS, which incorporated the good solubility and adsorption capacity of chitosan (CTS) into the excellent corrosion inhibition performance of polypyrrole (PPy) by in-situ polymerization of pyrrole on CTS. The corrosion inhibition performance of PPy-CTS composites as a potential corrosion inhibitor for Q235 carbon steel in 1 M HCl solution was investigated by electrochemical (potentiodynamic polarization curve and AC impedance spectroscopy) and surface morphological (scanning electron microscopy and water droplet contact angle) characterization. The results revealed that PPy-CTS with the optimal concentration of 250 ppm achieved the highest corrosion inhibition efficiency of 91.1%. Subsequently, the corrosion inhibition mechanism was furtherly studied. Gibbs free energy obtained from the Langmuir isotherm model suggested that the absorption of PPy-CTS corrosion inhibitor on Q235 steel in 1 M HCl solution belonged to a combined type of physisorption and chemisorption, which resulted in the formation of a physical barrier preventing the carbon steel from corrosion. In addition, the conductive polymer PPy of corrosion inhibitor possessed an oxide-film anodic protection for carbon steel. Ultimately, PPy-CTS effectively suppressed the corrosion reaction of carbon steel in harsh acidic environment through the synergistic effect of physical barrier and anodic protection.
Multidimensional Study On The Corrosion Inhibition of Polypyrrole-Chitosan (PPy-CTS) Composites For Carbon Steel In Acid Medium
