Research On Anodic Oxidation And Electrolytic Coloring Of Foamed Aluminum

The optimized parameters of foamed aluminum oxidizing technology were determined before its electrolytic coloring experiment. The surface of foamed aluminum was anodic oxidized by sulfuric acid oxidization solution. The parameters of oxidizing technology were optimized through orthogonal design method and the homogeneous and well-colored foamed aluminum was obtained. Electrolytic coloring of foamed aluminum was studied on the base of it. The potassium hypermanganate solution was selected as main-salt. Experiment conditions, such as the concentration of main-salt, electrolyzation time, electrolyzation voltage, electrolyte temperature and the concentration of sulfuric acid were used in the single-factor experiments. The corrosion resistance of the oxidation and coloration film was horizontally evaluated by its potassium dichromate resistant time. The optimized parameters of coloring technology were determined.Transverse section of foamed aluminum coloration film was observed under metallographic microscope. The pattern and thickness of coloration film were primarily analysed. The microstructure, thickness and the surface elementary content of oxidation film and coloration film were investigated by scanning electronic microscope and the surface composition of the film was measured by X-ray inflection. The results showed that the coloration film was homogeneous and compact and it was related to the surface curvature of foamed aluminum. Neutral salt spray fog test was used to all the specimens under the electrolytic coloring single-factor experiments. The coloration film that was prepared under the optimum oxidization process condition was done the fully immerse experiment in different concentration of CH3COOH, Na2CO3, HCl and NaOH. The results proved that the coloration film of foamed aluminum was of fine resistance to acid and alkali. Atmospherical exposure test showed that the coloration film was of fine resistance to sun-shine.The optimized technology parameters were determined through the study of foamed aluminum anodic oxidation and electrolytic coloring. The conclusion could be gained that the processing method of aluminum and its alloys oxidation and electrolytic coloring was adapted to foamed aluminum materials. But the process was required further improvement.