Effect of in-situ pre-soaking in seawater on the erosion-corrosion properties and micro-mechanism of nickel aluminium bronze alloy

The effects of pre-soaking in seawater on the corrosion behaviour of the nickel aluminium bronze alloy were examined using electrochemical and erosion-corrosion tests. The surface passive film of the alloy pre-soaked for 30 d consisted of an outer loose CuO film, a middle dense Cu2O film, and a denser inner Cu2O film contained Al2O3. The corrosion properties of the sample pre-soaked for 30 d were significantly improved, with ∼71% reduction in corrosion rate at 3 m/s compared with the unsoaked sample. Strong bonding between the substrate and passive films formed during pre-soaking effectively inhibited the entry of ions from seawater.