Corrosion Electrochemistry and Multi-layer Corrosion Product Characteristics of B10 Copper-Nickel Alloy Bends with Different Bending Angles under Seawater Erosion

Due to different bending angles, seawater pipeline systems are prone to severe erosion–corrosion under seawater erosion. This paper uses electrochemical testing methods, corrosion morphology and product analysis methods to study the erosion–corrosion behavior of seawater pipeline systems with different bending angles. It is found that the overall corrosion resistance of the outer arch side sample of the 150° bend is stronger than that of the inner arch side sample, while the corrosion resistance of different locations of the 90° bend from strong to weak is as follows: outer > inner > bottom. The sample in seawater at a flow rate of 3 m/s is difficult to generate a stable oxide film, and the total resistance during polarization also decreases overall. The sample surfaces of different locations of the bend are covered by a dark corrosion product film, which is a double-layer film. The outer layer of the corrosion product film is mainly composed of Fe and Ni, and hydroxides. The inner layer of the product film is mainly composed of hydroxides and oxides of elements such as Fe and Ni, and the oxide content is significantly increased compared to the outer layer.