Carboxymethylchitosan + Cu2+ mixture as an inhibitor used for mild steel in 1 M HCl

The inhibition effect of Carboxymethylchitosan (CMCT), Cu2+, and CMCT + Cu2+ mixture on the corrosion of mild steel in 1 M HCl has been investigated using gravimetric and electrochemical techniques. CMCT + Cu2+ mixture acts much more effectively than the inhibiting action of each additive separately. In addition, higher efficiency is achieved for the mixture of 20 mg L−1 CMCT + 10−4 M Cu2+. The efficiency of the optimal mixture increases with the temperature in the range 298–353 K. Activation energy of corrosion reaction in the presence of the optimal mixture of the inhibitors is much lower than that exhibited in 1 M HCl solution. The inhibition mechanism proposed in this paper is based on the results of conductometric investigations.