The inhibitive effect of 2-thiophene carboxaldehyde (TCAl) on zinc corrosion in 1 M H3PO4 solutions has been studied by weight loss, potentiodynamic polarisation and open-circuit potential (OCP) methods. The obtained results revealed that TCAl is an effective corrosion inhibitor for zinc in H3PO4 solutions. Inhibition efficiency values obtained from gravimetric and electrochemical measurements were in good agreement. The inhibition efficiency increases with increasing inhibitor concentration and decreases with increasing temperature. Potentiodynamic polarisation studies showed that TCAl acts as a mixed type inhibitor. Scanning electron microscopy (SEM), OCP measurements and the thermodynamic data of dissolution and adsorption processes showed that inhibition of zinc corrosion in phosphoric acid solutions by TCAl is due to the formation of a physisorbed film on the zinc surface. Adsorption of the compound studied on zinc surface obeys to Langmuir adsorption isotherm.
Corrosion, Inhibition, Zinc, Acid, Thiophene, Adsorption