Corrosion inhibition of mild steel using binary mixture of sesame and castor oil in brine solution

Binary mixture of sesame and castor oil has been investigated as a corrosion inhibitor for mild steel in brine solutions by weight loss, polarization techniques and scanning electron microscopy (SEM) analysis. Gas Chromatography-Mass Spectroscopy (GC-MS) analysis showed the presence of unsaturated compounds like oleic, steric and palmitic acid which are responsible for the corrosion inhibitory properties of the binary mixture. Optimum inhibition efficiency of 86.2% was predicted by Minitab 17 statistical software using the weight loss method at 0.79M brine concentration, 22.1 mg/L concentration of binary inhibitor and at a time period of 14 days. Tafel polarization plots affirm that binary mixture of sesame and castor oil acts as an effective mixed-type inhibitor in moderately low concentrations while it also acts as anodic and cathodic inhibitors in high concentration of brine. The results of the SEM analysis also indicate the inhibition efficiency of the binary mixture of mild steel.