A study of the use of polyaspartic acid derivative composite for the corrosion inhibition of carbon steel in a seawater environment

Abstract Corrosion inhibition performance of a polyaspartic acid derivative (PASP-AESA-ASP) composite on carbon steel in a seawater environment was studied by real-time tests using corrosion rate, electrochemical and weight loss methods. The composite was prepared by mixing the synthesized PASP-AESA-ASP with zinc sulfate and 2-hydroxyphosphonoacetic acid on a mass ratio of 15:4:6. The PASP-AESA-ASP composite showed a significantly better corrosion inhibition effect than PASP-AESA-ASP, zinc sulfate or 2-hydroxyphosphonoacetic acid alone, with the average corrosion rate of 0.005 mm/y and corrosion inhibition rate of 95% (based on weight loss) achieved. Electrochemical evaluation of the corrosion behavior using potentiodynamic scanning revealed the lowest corrosion rate (Icorr = 1.7 μA/cm2) for the PASP-AESA-ASP composite compared with 2.7 μA/cm2 and 5.3 μA/cm2 for the PASP derivative and uninhibited environments. Improved corrosion inhibition performance of the composite can be attributed to increased number of possible mechanisms working in unison, to include retardation of the metal dissolution and formation of protective films and compounds at the anodic/cathodic sites. The results reveal the potential for use of this inhibitor in applications such as desalination plants, and further improvements may be achieved through refinements in the composite blend design and ratios.