Rusting (corrosion) of ships is a complex chemical and electrochemical process. The main reasons include the high salinity of seawater, the characteristics of metal materials, and complex marine environmental factors. The following is a detailed analysis of the reasons why ships are prone to rusting:
1.Seawater contains a large number of chloride ions , which can penetrate the oxide protective film on the metal surface (such as the oxide layer of steel) and accelerate the corrosion of metals. 2. Chloride ions react with iron to form soluble chlorides, resulting in the continuous dissolution of the metal. Different metals are used in different parts of the ship (such as steel hulls and copper alloy propellers), forming a potential difference in the electrolyte (seawater), triggering the flow of current and causing the corrosion of the metal with a lower potential (such as steel). 3. Microorganisms such as sulfate-reducing bacteria (SRB) in the ocean attach to the surface of the ship’s hull, and their metabolism produces hydrogen sulfide and acidic substances, which damage the metal structure and accelerate corrosion. 4.Waves, sediment, floating ice, etc. impact the ship’s hull, damaging the anti-rust coating and exposing the metal. The cavitation effect generated when the propeller rotates at high speed peels off the surface protective layer.
Ship rusting is the result of the combined action of multiple factors, and comprehensive measures such as regular maintenance and coating protection are required to extend the service life of the ship.
