Corrosion of Pure Copper in Flowing Seawater Under Cavitating and Noncavitating Flow Conditions

Abstract

This paper investigates the corrosion of pure copper in flowing seawater under cavitating and non-cavitating flow conditions. Experiments were conducted in a 10 mm × 20 mm working section with a 60 deg symmetrical wedge cavitation source. A copper sidewall specimen was held under potentiostatic control and its average corrosion current was measured under different flow conditions. To facilitate a detailed investigation of the flow field upon the current distribution over the specimen surface, further tests were carried out using a sidewall incorporating 24 mini-electrodes. Apart from some indication of cavity shielding, corrosion currents were little affected by the presence of cavitation during the incubation period (when no material was being removed). However, under similar cavitation conditions (but with material removal under steady-state erosion conditions) the corrosion currents approximately doubled.