Corrosion inhibition of mild steel by acid extracts of prosopis juliflora

Corrosion of mild steel in 1 N HCl, 1 N H2SO4 and 1 N HNO3 solution at 299 +/- 2 K was studied - by mass-loss method in absence and presence of the acid extract of seeds, leaves and bark of Prosopis Juliflora (PJ). From the mass-loss data, it was concluded that the inhibition increased with the increase in the concentration of the additives for seeds in 1 N HCl while in the case of leaves and bark, the corrosion rates were found to decrease with the increase in concentration of extract up to 0.2% and then the reversal in trend of increase in concentration of 0.3% to 0.5%. In the case of 1 N H2SO4, the inhibition increased with the increase in the concentration of the additives for seeds, leaves and bark. In the case of 1 N HNO3, there is critical concentration of 0.2%, which shows maximum inhibition for seeds and leaves extract, while for bark extract the corrosion rates were found to decrease with the increase in the concentration of additives.