The Inhibitive Performance of Fenugreek for Corrosion of Copper and Nickel in Sulfuric Acid

Fenugreek extract was examined as a corrosion inhibitor for copper and nickel in 2.0 M H2SO4 solution by gravimetric and electrochemical measurements. Scanning electron micrographs showed that the surface damage is decreased in inhibited acidic solution for both metals. The maximum inhibition efficiencies were 85.6% and 83.5% for copper and nickel, respectively, by using 20% (V/V%) of fenugreek extract in H2SO4 solution. Adsorption of fenugreek on both metals follows Langmuir adsorption isotherm. Florry-Huggins isotherm can be applied successively only in case of nickel suggesting a chemisorptions mode at later stages of adsorption process. Linear polarization and impedance measurements prove the inhibition ability of fenugreek for copper and nickel corrosion in H2SO4 solution.