Study on the inhibition performance of succinic anhydride-nonylphenol polyoxyethylene ether copolymer and iodide ions towards the corrosion of Q235 Steel in 1M HCl

The corrosion inhibition performance of NPSA towards the corrosion of Q235 steel in 1 M HCl and the synergistic effect between iodide ions and NPSA were studied using electrochemical method (OCP, Tafel and EIS) and weight-loss method. The metal was protected in the test solution containing NPSA, while the surface was well protected by the inhibitor mixture. The corrosion inhibition efficiency increased with the increase in the inhibitor concentration, and the maximum inhibition efficiency reached 98.9%. The NPSA molecule and iodide ions formed a complex in the bulk solution and then adsorbed on the metal surface; the active reaction sites were blocked with predominant control of the cathodic reaction. The adsorption configurations changed, and –OH adsorbed on the metal surface due to the presence of iodide ions. The adsorption inhibitor molecules changed from physical adsorption to chemical adsorption; the metal surface was well protected.