The corrosion inhibition of nickel in 0.5 M H2SO4 by cysteine was investigated with various electrochemical methods and surface observations by SEM. The cyclic voltammetry revealed that the current density is the highest in absence of the cysteine and decreases with increasing inhibitor concentration. The cysteine is an anodic inhibitor. The polarization and electrochemical impedance spectroscopy showed that the cysteine has a poor inhibitive effect. The surface observation by scanning electron microscope corroborates the addition of cysteine has no significant improvement of the surface morphology of nickel electrode in 0.5 M H2SO4. Results obtained by different methods corroborate each other.
