Erosion corrosion of copper-nickel alloys in sulfide polluted seawater

Abstract EN

The corrosion resistance of copper-nickel alloys in sulfide polluted seawater was investigated under simulated jet impingement conditions.

Mass transfer coefficients of the cell were measured electrochemically.

The maximum negative shift in potential of copper nickel alloy in sea water occurs at a jet clearance parameter (H/d, Electrode to nozzle distance/electrode diameter) of 1.329 where the maximum value of mass transfer coefficient occurs.

A general corrosion mechanism is adopted to explain the corrosion behavior, based on the principal of treating corrosion as a heterogeneous chemical reaction, which results in an accurate explanation of the experimental results, otherwise misinterpreted by some of the previous investigators.

The mechanism shows that three steps control the rate of corrosion: external mass transfer resistance; internal mass transfer resistance; and reaction kinetics.

For high sulfide concentrations the corrosion of cupronickel alloys is controlled by kinetic and internal mass transfer resistance.

For the lower sulfide system the reaction is under diffusion control and internal mass transfer resistance.