Phenazone and aminophenazone as corrosion inhibitors for aluminum in HCl solution

The corrosion behavior of aluminum in 1 M HCl solution in the absence and presence of phenazone and aminophenazone was investigated using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The results of these techniques show that, the inhibition efficiency of these compounds depends on their concentration and chemical structure. The inhibitive action of these compounds was discussed in terms of blocking the electrode surface by adsorption of the molecules through the active centers contained in their structure. The adsorption process was found to obey Temkin isotherm model. The effect of temperature on the rate of corrosion in the absence and presence of these compounds was also, studied. Some activated thermodynamic parameters were computed and discussed. Potentiodynamic polarization data indicated that these compounds act as cathodic type inhibitors. From impedance data it is found that the corrosion of aluminum is controlled by charge transfer process at all concentrations of inhibitors. Quantum chemical parameters were constructed in order to characterize the inhibition performance of the tested molecules.