Study the effect of cerium ions and cerium oxide nanoparticles on corrosion and self-healing behavior of chitosan-based coatings on AA5083-H321

In this study, synthesis of self-healing CeO2-chitosan (CeO2-CHIT) nanocomposite coatings on AA5083-H321 by dip immersion method was investigated. Corrosion and self-healing behavior of the coatings were studied by using electrochemical impedance spectroscopy (EIS) and salt spray. SEM, TEM, TGA and FTIR were used to characterize the resulting coatings. The result showed that upon increasing the cerium ion concentration in chitosan (CHIT) films from 1 to 5 mM, corrosion current density values significantly decreased. Also, the results revealed that the presence of CeO2 nanoparticles in CHIT coatings doped with Ce (III) ions (CHITCE) significantly enhanced the corrosion resistant of the coating. Thus, CeO2-chitosan nanocomposite coating doped with 5mM Ce(III) ions was selected as the optimum coating to study the self healing properties. This coating showed high impedance after 12hr of immersion in 3.5% NaCl. With further increase in immersion time from 12 to 24, 48 and 72 h, this trend continued to increase in corrosion resistance. This result showed that this coating exhibits ‘self-healing” type behavior.