The inhibition of copper corrosion in 3.5% NaCl solution has been studied at 25oC using three inhibitors 1-phenyl-2,5-dithiohydazodicarbonamide (Inh I), 1-p-methoxyphenyl-2,5- dithiohydrazodicarbonamide (Inh II) and 1-p-chlorophenyl-2,5-dithiohydrazodicarbonamide (Inh III). The inhibition efficiencies of these compounds have been evaluated by weight loss and electrochemical methods (Impedance spectroscopy and polarisation curves). The surface study was done by using SEM and ESCA techniques. The inhibition efficiencies of the inhibitors follow the sequence. Inh II > Inh I > Inh III. The inhibitors Inh I, Inh II and Inh III appears to inhibit corrosion process through formation of protective film which was found to consist of Cu(I)-inhibitor complex, cuprous chloride CuCl or CuCl2 - complex ion or both on the surface.
