Inhibition Effect of Aromatic Aldehydes on Cold Rolled Steel in H3PO4 Solution

The inhibition effect of three aromatic aldehydes of protocatechualdehyde (3,4-dihydroxy-benzaldehye),vanillin (4-hydroxy-3-methoxy-benzaldehyde) and cinnamaldehyde (3-phenyl-acraledehyde) on cold rolled steel (CRS) in 3.0 mol/L H3PO4 solution was investigated by weight loss and potentiodynamic polarization curve methods.The results showed that the inhibition efficiency (IE) of aromatic aldehydes increased with the increase of inhibitor concentration and the aromatic aldehydes were cathodic-type inhibitors.The adsorption of aromatic aldehydes on CRS surface obeyed the amended Langmuir adsorption isotherm equation.IE values followed the order:cinnamaldehyde>vanillin>protocatechualdehyde.