Study On Anodic Aluminum Oxide And Coloring Technology

Aluminum is one of the most widely distributed nature metal elements.Aluminum and its alloy are being utilized in the world due to a number of advantages compared with other metal.A thin oxide film can form on the surface of the aluminum alloy in natural environment.But the structure of this amorphous film is loose,it could not provide good corrosion resistance.Anodizing could greatly improve the corrosion resistance and decorativeness of aluminum.In order to prevent the oxidation of aluminum surface,anodic oxidation is used for the protective treatment.The research object of this thesis is 2024 aluminum alloy.Anodic oxidation film were prepared on the surface of the aluminum alloy sample,and the coloring treatment were proceed by making use of porosity of the film.In this thesis,alumina oxide films were prepared by both oxalic acid anodizing electrolyte and sulfuric acid anodizing electrolyte.In oxalic acid method,two different power supply parameters,the constant current or the constant potential,were used in oxidation progresses.In sulfuric acid method,different testing time were used in oxidation progresses.The prepared aluminum oxide films were characterized with the help of scanning electron microscopy and the X-ray diffraction.Membrane surface roughness were measured by roughness measuring instrument.The results showed that the different current density and voltage parameters used in the process of anodic oxidation affected the morphology and structure of the aluminum oxide films.The porous alumina oxide films prepared by both oxalic acid and sulfuric acid anodizing electrolyte were crystalline structures.In this thesis,coloring and sealing technology were researched and the performance of samples were measured.In coloring technology,AC electrolytic process in nickel salt and organic dye adsorption shading treatment were researched.In sealing technology,water sealing and nickel salt sealing were researched.Hardness test results showed that anodic oxidation could increase hardness of the samples.Performance tests showed that anodic oxidation could enhance abrasion resistance and corrosion resistance of the aluminum alloy.