为保证7075铝合金硬质阳极氧化膜颜色的均匀一致性,以7075铝合金作为研究对象,采用DOE分析方法,从工艺参数对7075铝合金硬质阳极氧化膜颜色的影响着手,分别测试不同氧化温度(-6、-3、0、4、8 ℃)、不同氧化电流密度(2、4、6 A/dm2)、不同硫酸含量(150、200、230、240、250、300 g/L)、不同膜层厚度(20～80 μm)、不同装载位置对硬质阳极氧化膜颜色的影响。结果表明:随着温度的升高和电流密度的降低,试样的色差值逐渐降低。当电流密度为2 A/dm2,温度为4 ℃[实际控制在(4±1)℃范围内],硫酸浓度为200～230 g/L时,试样的氧化膜颜色与样件最接近。当膜层厚度为20～80 μm范围内时,随着氧化膜厚度的增加,试样的氧化膜颜色不断变深,颜色从淡浅黄色到黄褐色、棕褐色,当厚度为80 μm时,膜层颜色变为青砖色。不同装载位置对试样的氧化膜颜色无明显影响。
To ensure the uniformity and consistency of the color of the hard anodic oxidation film of 7075 aluminum alloy, 7075 aluminum alloy was chosen as the research subject in this study. Utilizing the design of experiments (DOE) analysis method, the impact of process parameters on the color of the hard anodic oxidation film of 7075 aluminum alloy was investigated. The effects of different oxidation temperatures (-6, -3, 0, 4, 8 ℃), different oxidation current densities (2, 4, 6 A/dm2), different sulfuric acid contents (150, 200, 230, 240, 250, 300 g/L), different film thicknesses (20～80 μm), and different loading positions on the color of the hard anodic oxidation film were tested. Results showed that as the temperature increased and the current density decreased, the color difference value of the oxide film gradually decreased. When the current density was 2 A/dm2, the temperature was maintained at 4 ℃ [with a control error of (4±1) ℃], the concentration of sulfuric acid was 200～230 g/L, the color of the oxide film closely matched that of the original sample. At a film thickness ranging from 20 to 80 μm, the color of the oxide film on the sample progressively darkened as the thickness increased, transitioning from light yellow to yellowish-brown and eventually to chocolate-brown. At a thickness of 80 μm, the film’s color changed to blue brick. Different loading positions had no significant effect on the color of the oxide film.
