Corrosion inhibition of mild steel in seawater through green approach using Leucaena leucocephala leaves extract

• W.M.K.W.M. Ikhmal^1,2, M.F.M. Maria^1,2, W.A.W. Rafizah^2,3, W.N.W.M. Norsani^2,3 and M.G.M. Sabri^1,2,4

¹ Advanced Nano Materials (ANoMa) Research Group, School of Fundamental Science, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia
² Materials and Corrosion Research Group, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia
³ School of Ocean Engineering, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia
⁴ Institute of Biodiversity and Sustainable Development, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia

Abstract: Corrosion inhibition analysis of Leucaena leucocephala leaves extract (LLE) as an additive incorporated into a commercialized coating to protect mild steel when immersed in seawater has been successfully conducted. The procedures involve the utilization of multiple techniques including Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis), electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and scanning electron microscope with energy-dispersive X-ray spectroscopy (SEM/EDS). The result of FTIR identified both hydroxyl (–OH) and carbonyl (C=O) groups indicating the presence of phenolic compounds in the extract whereas the analysis obtained from UV-Vis showed a peak absorption spectrum at 268 nm. The electrochemical analysis indicated an excellent inhibition efficiency up to 96.12% for the immersed mild steel coated with 6% of LLE coating. Furthermore, based on the study of polarization, a drastic decrease of corrosion rate at 0.2791 mm/year was observed for the same coating as compared to the uncoated substrate, which was 2.3991 mm/year. The study also confirmed that LLE acts as a mixed type inhibitor, as shown in the polarization curve. The morphological evaluation displayed a smooth and homogenous surface with less salt precipitation for 6% of LLE coating as compared to other types of coating affirming it to be the optimum concentration for this evaluation study.

Keywords: stainless steel, corrosion, coating, seawater, plant extract

Int. J. Corros. Scale Inhib., 2019, 8, no. 3, 628-643 PDF (1 265 K)
doi: 10.17675/2305-6894-2019-8-3-12

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