Effect of Schiff's bases Structure on Corrosion Inhibition Efficiency of Copper in Chloride Solutions

Self -assemble monolayers of different Schiff bases were prepared on a copper surface. EIS, SEM and quantum chemical calculation was used to investigate the relationship between Schiff base structure and corrosion inhibition efficiency. Experimental and computational results showed that the main active regions of these compounds were the characteristic group of imine or methylenimine (- RC = N) and -OH on the benzene rings. The Schiff base reacted with copper to form a chelate covering the surface of copper, which acted as a protective agent for copper, rather than a simple geometric covering effect. The introduction of electron -substituted group into the benzene ring of Schiff base can improve the inhibition efficiency The more the substitution group moved to -C=N-,the more stable the chelate was, and the higher the inhibition efficiency was.