Evaluation of Synergistic Effect of Plant Extracts for Cathodic Inhibition of Steel in Acidic Media

The synergistic effect of combining both Sida acuta (SA) and Jatropha curcas (JC) leaf extracts on steel in 1.0 M HCl solution was investigated using gasometric and conventional o o weight loss technique at 30 C and 50 C. Surface microscture of the steel with the mixed extract werestudied through Scanning electron microscope(SEM) and Electron dispersive X- ray spectroscopy (EDX) which revealed how the inhibitor hindered the attack of acid on the microstructures thereby preventing its dissolution into the corrodent. The presence of C=O -1 functional band at 1094 cm of ester was confirmed by Fourier transform infrared analysis. o o Synergism Parameter(S1) was at optimum at 2.09 and 2.65 at 30 C and 50 C respectively on steel pipe. This implies that synergism is favoured with increasein temperature. S1 greater than 1 confirmed that the mixture of the two plants produced synergised inhibitive effect. The inhibitory power increases with increase in extract concentration. Inhibition Efficiency -3 rangesfrom 60 % to 85 % with increasein extractconcentration of SAalonefrom 0.1 gdm to -3 o 1.0 gdm . When synergisedwith JC, itrangesfrom 77 % to 93 % for SA at 30 C forthesame concentration increase. Results obtained showed that thesynergeticeffects of the plantsextract complimented carbon constituent of the steel to enhanced the corrosion inhibition potential synergized plantextracts overunsynergized onthe steel.