Inhibition Effect of PASP on Carbon Steel in Nitric Acid Solution Evaluated by Electrochemistry Methods

Corrosion inhibition performane of polyaspartic acid (PASP) for carbon steel in 0.1 mol/L nitric acid solution was studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS).The results showed that the inhibition efficiency increased with increasing PASP concentration at 20℃.When PASP concentration was 0.5 g/L,the inhibition efficiency was 85.3%.The PASP is a mixed type inhibitor which restrains cathodic reaction.Equivalent circuit was obtained as R(RC)((RW)Q) by EQU from electrochemical impedance data．