Some azodyes as corrosion inhibitors for iron in HCl solution

The inhibitor effect of the quinazol-4-one derivatives on the corrosion of iron in hydrochloric acid solution was investigated. Polarization curves indicated that these compounds act as mixed type inhibitors, but the cathode is more preferentially polarized. The effect of structural changes in these compounds on their inhibition efficiency has been studied. The inhibitors appear to function through general adsorption following the Langmuir adsorption isotherm. Results indicate that the rate of corrosion of iron increases with increasing temperature over the range 27-50°C both in absence and in the presence of inhibitors. Some thermodynamic functions were also computed and are discussed.