Study on the erosion-corrosion behavior of copper-nickel alloys in high temperature and high humidity marine environment

Abstract This paper focuses on the study of B10 copper-nickel alloy, utilizing a self-designed tubular flow erosion device to simulate the seawater environment. Various testing techniques, including electrochemical impedance spectroscopy (EIS), potentiodynamic polarization curve measurements, and X-ray energy dispersive spectroscopy (EDS) analysis, were employed to investigate the erosion-corrosion behavior of B10 alloy in the South China Sea seawater. Combined with the observation of corrosion morphology and compositional analysis, the influence laws of different time durations, temperatures, and flow velocities on the initial erosion-corrosion of B10 alloy were discussed. The results indicated that during erosion tests conducted in dynamic seawater with a flow velocity of 3 m/s and a temperature of 40°C for varying durations (30 minutes, 1 hour, 2 hours, and 4 hours), the highest corrosion potential was observed at 2 hours, with an oxygen (O) elemental weight percentage of 16.34%. As the erosion time increased, the oxide layers on the B10 surface gradually became denser. When erosion tests were conducted at a flow velocity of 3 m/s and an erosion time of 2 hours, but with varying temperatures (30°C, 40°C, and 50°C), the results showed that at 40°C, the erosion traces on the B10 surface were pronounced, indicating severe corrosion. At 50°C, the oxide layers on the material surface were relatively dense, accompanied by a higher number of rust blisters. The O elemental content was the lowest. In tests conducted at a temperature of 40°C, an erosion time of 2 hours, but with varying flow velocities (1 m/s, 2 m/s, 3 m/s, and 4 m/s), it was found that at a flow velocity of 3 m/s, the erosion traces were most evident, with large and numerous corrosion pits. However, at a flow velocity of 4 m/s, the oxide layers on the material surface were denser. The corrosion traces were gradually covered by a passivation film, rendering the corrosion pits less apparent.