Inhibition Effect of Newly Synthesised Piperidine Derivatives on the Corrosion of Brass in Natural Seawater

摘要

The piperidine derivatives, namely (4-hydrazono-3-Methyl-2,6-diphenyl-piperidin-l-yl)-etha-noic acid hydrazide (HMDPEH), 5-(2,6-Diphenyl-3-methyl-4-hydrazono-piperidin-l-ylmethyl)-3H-[l,3,4]oxadiazole-2-thione (DMHPOT) and 4-Amino-5-(2,6-diphenyl-3-methyl-4-hydrazono-piperidm-l-ylrnethyl)-4H-[l,2;4]triazole-3-thiol (ADMHPTT) were synthesised. The inhibiting effect of these compounds on the corrosion of brass in natural seawater was studied using potentiodynamic polarization studies and electrochemical impedance spectroscopic (EIS) measurements. The presence of these organic compounds in seawater suppresses both anodic and cathodic processes, and it is enhanced by the increase in the concentration of the inhibitors. The value of the activation energy (E_a) for the corrosion of brass was calculated and discussed. The structural and electronic parameters of these piperidine derivatives were calculated using computational methodologies. The surface morphology of the brass after its exposure to natural seawater with and without 10~(-3)M HMDPEH, DMHPOT and ADMFfPTTwere examined by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX).