With the development of shipping industry in various countries and the need of efficiency, more and more high-speed passenger ships use aluminum alloy as the hull structure and material. The composition of seawater is complex and the corrosion of the hull is also very serious. Oxygen, chloride ions and complex sea creatures in seawater are the main factors of seawater corrosion. Various ions such as chloride ions constitute an electrolyte solution, which makes seawater corrosion have the characteristics of electrochemical corrosion.
Due to its high strength/mass ratio, ease of forming, and excellent physical and chemical properties, aluminum and its alloy materials are the second-largest class of metal materials after steel. Under atmospheric conditions, the aluminum alloy immediately forms a natural oxide film on its fresh surface. This oxide film is very thin, generally in the range of 0.005 to 0.015 μm, and is easily damaged. It dissolves rapidly under acid and alkaline conditions. At the same time, the aluminum alloy material has low hardness and poor wear resistance. Therefore, aluminum alloys must undergo corresponding surface treatment before use to meet their environmental adaptability and safety, reduce corrosion, and extend service life. Anodised aluminum marine grade plate through proper surface oxidation treatment, the thickness of the oxide film can be increased by 100 to 200 times.
 


The anodizing method is called the "universal" technology of aluminum alloy surface treatment, and it is the most widely used; the thickness of the anodized aluminum marine grade plate can reach tens to hundreds of microns, which not only has good mechanical properties and corrosion resistance And, it also has strong adsorption performance, and it can get beautiful decorative appearance after adopting various coloring methods.