Inhibitory Effect of Trigona Sp. Propolis Extract on Corrosion Rate of API 5L-B Steel in a Corrosive Medium

The effectiveness of inhibitor extract of Trigona sp. propolis (IETP) as the corrosion inhibition of API 5L Grade B steel was studied in the corrosive environment of 3.5% NaCl solutions is systematically presented. The use of selected organic corrosion inhibitors is a new alternative as one type of inhibitor that is non-toxic, inexpensive, available in nature, and environmentally friendly. IETP as an organic corrosion inhibitor has been characterized and analyzed in this study. The main compound in the inhibitor was identified based on the Fourier transform infrared spectroscopic analysis. The chemical compound of the propolis solution is flavonoid-rich in oxygen atoms, which play an important role in the inhibition process. Inhibition behavior was investigated through weight loss testing and the polarization methods on API 5L Grade B steel material in 3.5% NaCl media with variations of the addition of inhibitors 0 ml, 2 ml, 4 ml, 6 ml, 8 ml, and 10 ml into the solution. The results showed that the IETP was quite effective in corrosion medium with a solution of NaCl 3.5%. The 10 ml IETP had the highest effect decreasing the corrosion rate from 3.469 to 2.272 mpy. Optimal and effective levels in the use of IETP is 10 ml with the highest level efficiency of 79%. The polarization curve through the potentiodynamic technique showed that the inhibitor has a tendency for the cathodic inhibitor mechanisms by absorption and simply blocking the reaction on the metal surface.