Corrosion behaviour of Monel in phosphoric acid

Nickel alloys are widely used as constructional materials in chemical processing industries. They are very resistant to pitting and crevice corrosion. In the present work, the corrosion behaviour of Monel in phosphoric acid of different concentrations has been studied by weight loss and electrochemical methods. It has been observed from the polarization studies that the passivation range slightly varies with H₃PO₄ concentration. The nature of the passive film has been investigated using the electrochemical impedance method.