Caffeine as a Green Corrosion Inhibitor for Carbon Steel in Corrosive Media

In this report, the corrosion inhibition of carbon steel in acidic media is done using
caffeine as green inhibitor in hydrochloric acid. The inhibition efficiency of the
green corrosion inhibitor was performed using weight loss measurement, Tafel plot
and linear polarization resistance method. Weight loss measurement is conducted in
samples containing different concentrations of caffeine 0%, 1%, 1.5%, 2%, 2.5%,
3%. The weight loss measurement is done to measure the mass change in the carbon
steel coupons in corrosive solution after an interval of 3 days for a month. The
inhibition efficiency performance of the 3% solution has reached 67%. It was
obvious that with increasing the concentration of the inhibitor, the weight loss is
reduced. The second part of this study was investigating the inhibiting influence
using Tafel plot, Linear Polarization Resistance (LPR), and Electrochemical
Impedance Spectroscopy (EIS). The results have shown great inhibition efficiency
performance of the caffeine inhibitor in the corrosive media.