Inhibition of corrosion on AISI 4137 steel in H2SO4 using Cascabela thevetia and Jatropha curcas leaves

Abstract: Inhibition of corrosion on AISI 4137 steel in H2SO4 using Cascabela thevetia and Jatropha curcas leaves 

as inhibitor was studied using gravimetric and gasometric analysis. It was found that the leaves extract of both 

plants act as a good corrosion inhibitor for AISI 4137 steel in all concentrations of the extract ranging from 0.3 - 

1.5 g/l and the inhibitive efficiency increases with increasing concentration of inhibitor. Cascabela thevetia has 

better surface coverage than Jathropha curcas with their surface coverage been 0.68 and 0.61 respectively. As the 

concentration of the inhibitors increases the evolution of the gas decreases with the highest evolution been 23 cm3 

and 22 cm3

 at 0.3 g/l concentration for both Cascabela thevetia and Jathropha curcas respectively in 7 minutes. 

Cascabela thevetia and Jatropha curcas leaves extract are recommended for use in industries as a replacement for 

toxic chemical inhibitors. 

Key words: Corrosion inhibitor, Cascabela thevetia, Jathropha Curcas, Surface coverage, gasometric, gravimetric 

and inhibition efficiency