Inhibitory efficiency of oxalic Nphenylhydrazide-N9-phenylthiosemicarbazideon corrosion of carbon steel in 0.5M H2SO4

International audience; The inhibitory effect of an oxalic type organic compound oxalic N-phenylhydrazide-N9-phenylthiosemicarbazide on the corrosion of carbon steel in 0.5M H2SO4 aqueous solution wasinvestigated by different experimental methods; gravimetry, voltammetry and electrochemicalimpedance spectroscopy. The surface state of the electrode after immersion of the steel couponsin corrosion test solutions, in absence and in presence of the inhibitor was characterised byscanning electron microscopy. The potentiodynamic polarisation measurements showed that thepresence of the inhibitor in 0.5M H2SO4 decreased both cathodic and anodic processes. Theaction of this inhibitor is therefore of a mixed type. The electrochemical impedance measurementsshowed the adsorption of the inhibitor. The inhibitory efficiency reaches a value of 95% at aninhibitor concentration of 1023M.