Abstract
An environmentally friendly green inhibitor based on clove flower buds aqueous extract was applied for corrosion inhibition of stainless steel 304 surface in 0.5 M HCl solution. Applying integrated experimental techniques (electrochemical combined with weight loss and surface morphological) the clove flower buds aqueous extract inhibition properties were examined. Potentiodynamic polarization curves indicated that clove extract acts as anodic type inhibitor. EIS measurements showed that the charge transfer resistance and consequently the inhibition efficiency increase with increasing concentration of clove with values above 90% at 12 ppm extract. The results obtained from the weight loss method confirmed those of electrochemical techniques. The results proved that the corrosion process was controlled by adsorption of the clove molecules on the stainless steel 304 surface through diffusion control. The optical micrographs are in agreement with those of electrochemical techniques which lead to confirmation of the ability of clove aqueous extract to protect stainless steel 304 and to retard its corrosion in 0.5 M HCl solution. Application of the adsorption isotherms have been evaluated and indicated that the adsorption mechanism is best described by each of the Flory-Huggins isotherm and kinetic-thermodynamic model. However, Langmuir isotherm is not applicable which clarified that the adsorption process is non-ideal.