Corrosion inhibitory characteristics of Jatropha curcas on Zinc alloy in 1.5m HCL solution

This work investigated the corrosion behaviour of Jatrophacurcas (JC) crude leave extract on zinc metal in the presence of 1.50 MHydrochloric acid solution at 28oC by hydrogen evolution (Gasometric) method. The results revealed that JC effectively inhibited the induced corrosion of zinc in the HCl solution. Inhibition efficiency increases as in extract concentration increases with optimum efficiency at 50v/v%. Corrosion rate retarded with increase in extract concentration. Specific reaction constant and Half-life of metal in the media are 6.251726928 x10-8 and 0.110872913 x108 minutes respectively. Four adsorption isotherms were employed. Langmuir isotherm best explains the physical adsorption interface mechanism between the extract and its adsorbed layers formed on the zinc surface with a correlation coefficient (R2) of 0.990. Free energy of adsorption of - 5.87KJmol-1 indicated a spontaneous process of physical adsorption of the extract on the zinc surface. Surface morphology were studied with Scanning Electron Microscope (SEM) and Electron dispersive X-ray spectroscopy (EDX) which revealed the protection of the internal grains of the metal from dissolution into corrodent provided by the adsorbed film the extract.