Inhibitive action of Vernonia amygdalina on the corrosion of aluminium alloys in acidic media

The action of Vernonia amygdalina (bitter leaf) on the acidic corrosion of 2S and 3RS alloys aluminium was studied using the weight loss method. The corrosion rates and inhibition efficiencies of the various aluminium coupons in the extract were calculated. The average corrosion rates of 6.5×10 −3 and 5.5×10 −3 mpy were obtained for 2S and 3SR alloys, respectively, in 0.1 M HNO 3 while 18.2×10 −3 and 10.4×10 −3 mpy were calculated for the 2S and 3SR alloys in 0.1 M hydrochloric acid (HCl), respectively. The results further showed the highest inhibition efficiency of 49.5% for the 0.1 M HCl and 72.5% for 0.1 M HNO 3, respectively. However, the 0.2g/l concentration showed a better performance in the inhibition of 0.1 M HCl for all samples.