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Aluminum is the most widely distributed metal elements in nature, very excellent physical, mechanical and processing properties, has been widely used in various fields of everyday life, but we use aluminum and its alloy products over a single color, just relatively simple color such as white, black, and the impact of its application in the field of decorative and optical equipment, far can not meet the needs of people. The aluminum and its alloys have more color to get rich colors, gorgeous products, is a very promising issue. Coloring the film prepared by micro-arc oxidation technology not only has excellent wear and corrosion properties, also has a color, variety, color stability, can be widely used in the automotive, machinery, aerospace, decoration and other industries. This article LY12 aluminum alloy matrix as experimental material. Different colorants added to the electrolyte by the method of micro-arc oxidation ceramic film on its surface a layer of color. Colorants film color, and process parameters were optimized. TT240 digital eddy current thickness gauge micro-arc oxidation film thickness measurement; OLS3000 laser confocal microscope and the German company Carl Zeiss (Carl Zeiss Jena) EVO 18 scanning electron microscope, the detection of micro-arc oxidation film layer surface morphology, three-dimensional morphology, pore size and pore depth; The MAO coatings chemical composition of British Oxford X-Max spectrometer; micro-arc oxidation film phase composition using X-ray diffraction (XRD) analysis; MATLAB software quantitative analysis of micro-arc oxidation film scanning electron micrograph of the surface; surface roughness of the surface roughness measuring instrument measuring micro-arc oxidation ceramic coating; immersion corrosion test and electrochemical corrosion tests on film corrosion resistance characterization. Determine the best content and energy parameters of the film colorants, and the following conclusions: (1) micro-arc oxidation green ceramic membrane electrolyte formula and energy parameters: electrolyte formula and colorant content: 9g / L Na 2 SiO 3 4g / L NaOH 2g / L EDTA-Na 2 2.0g/LK 2 Cr < sub> 2 O 4 , the current density 7A/dm 2 , duty cycle of 30%, the oxidation time 9min 1 3min pulse frequency 550Hz 8 50Hz. (2) micro-arc oxidation the best brown ceramic membrane electrolyte formulations and energy parameters: electrolyte formulations and coloring agent content: 9g / L Na 2 the SiO 3 4g / L NaOH 2g / L EDTA-Na 2 1.5g / L CuSO 4 , the current density 5A/dm 2 , the duty cycle of 20% < sup> 3 0%, the oxidation time 12min, pulse frequency 550Hz 8 50Hz. (3) be added to the electrolyte potassium dichromate preparation of micro-arc oxidation green ceramic membrane. The absence of coloring agents, the preparation of the film layer is white, while the K 2 Cr 2 O 4 was added to the electrolyte, the film started to show green. With the the K 2 Cr 2 O 4 concentration increased, the film color gradually deepened. Green film EDS analysis confirmed that the addition of Cr element makes the film turns green. With the increase in the concentration of the coloring agent, the pores of the film surface becomes large, the porosity increases, the corrosion resistance can be improved. (4) to study the impact of the current density the green ceramic membrane micro-arc oxidation. As the current density increases, the film becomes thicker and darker in color, the surface becomes rough, the holes reduce the number, the pore diameter and depth are increased, the porosity is also increased. When the current density is very small or great, corrosion resistance of the film is not good. (5) a pulse frequency of green ceramic membrane micro-arc oxidation. With the increase in the frequency of the pulse, the film thinning, lighter color, smooth surface more and more. Obtained under the film in the low frequency surface pores smaller, more molten particles, porosity is also large, uneven film surface. Pore ??volume can be reduced by increasing the frequency, and the film becomes uniform and smooth. (6) to add copper sulfate preparation of micro-arc oxidation brown ceramic membrane electrolyte. The absence of a colorant, the film layer was prepared as a white, was added to the electrolyte of CuSO 4 after the film began to show a brown, and with CuSO 4 concentration The rising film color gradually deepened, the high concentration of colorants, make the film surface ablation. Brown film EDS analysis confirmed that the addition of the Cu element makes the film has turned brown. With the increase in the concentration of the colorant of coating the surface of the pores, the average pore size and pore depth becomes large, the porosity increases, the film is more rough, and the corrosion resistance of the coating layer is first increased and then decreased. (7) studied the oxidation time micro-arc oxidation brown ceramic membrane. When the oxidation time, the color of the layer becomes deeper, increasing the thickness of the holes reduce the number of volume increases, the increase in porosity, surface more rough, undulating exacerbate corrosion resistance over time increase first become stronger and weaker. (8) to study the impact of the duty cycle of the micro-arc oxidation brown ceramic membrane. Darken after the first shallow film color with increasing duty cycle, the film thickness decreased and then increased pore volume smaller before larger, its corrosion resistance detection. When the duty cycle is too small or too large, the corrosion rate of the coating layer is very large, the denseness of the coating layer Poor performance is not good.
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