Corrosion and impressed current cathodic protection of copper-based materials using a bimetallic rotating cylinder electrode (BRCE)

A bimetallic rotating cylinder electrode (having individual electrode areas of 10 cm2 and rotating at 200-1400 rpm) has been used to examine the corrosion and protection characteristics of copper/nickel aluminium bronze and 90-10 copper-nickel/nickel aluminium bronze galvanic couples in filtered seawater at 25 °C. The flow-influenced electrochemistry of the systems was determined using zero resistance ammetry, corrosion potential measurements and a potential step current transient technique. In each case, the galvanic corrosion potential and corrosion rate displayed a Reynolds number dependency where mass transport control of the anodic dissolution reaction partially controlled the reaction rate. Bimetallic impressed current cathodic protection (ICCP) has also been demonstrated for a range of applied protection potentials and Reynolds numbers. A comparison has been made between the directly measured bimetallic ICCP current demand and that determined from independent, single-metal rotating cylinder electrode measurements. In this case, the mixed charge and mass transport controlled rate of oxygen reduction was examined.