INFLUENCE OF ANIONS ON THE PERFORMANCE OF ANISIDINES AS INHIBITORS FOR THE CORROSION OF MILD-STEEL IN ACIDIC SOLUTIONS

The influence of anisidines on the corrosion of mild steel in 1N HCl a nd 1N H2SO4 has been investigated by weight loss, gasometric and some other electrochemical techniques. Anisidines are found to be inhibitiv e in 1N HCl. In 1N H2SO4, o-anisidine inhibits the corrosion at all co ncentrations, whereas m-anisidine inhibits at concentrations more than 20 mM. However, p-anisidine accelerates the corrosion at all concentr ations. They behave predominantly as cathodic inhibitors in 1N HCl and inhibit the corrosion in 1N H2SO4 These bring down the permeation of hydrogen through mild steel in 1N HCl and enhance it in 1N H2SO4 The a dsorption of anisidines on the metal surface is found to obey Langmuir 's adsorption isotherm.