An insight into the passivation of cupronickel alloys in chloride environment

Cupronickels offer enhanced corrosion protection in marine environments by the formation of passive films on the surface. Cyclic voltammetric studies were carried on cupronickels in chloride solutions at pH 6,3 to understand the role of chloride ions in passive film formation. Increase in nickel content of the alloy and of chloride ions in solution decreases film resistance. Chloride ions take part in reduction of the passive film to copper. A solid-state model for passive film formation involving chloride ions has been attempted.