铝合金阳极氧化及电沉积二氧化硅制备热控涂层

发布时间：2018-01-21 12:41

  本文关键词： 铝合金 阳极氧化 电沉积 二氧化硅 热控涂层　出处：《南昌航空大学》2016年硕士论文　论文类型：学位论文

【摘要】：本文研究了铝合金阳极氧化以及电沉积二氧化硅制备热控涂层。研究了铝合金阳极氧化工艺对光学性能αs/εH的影响,确定制备低比值αs/εH热控涂层阳极氧化工艺。在制备低比值αs/εH的阳极氧化工艺基础上,用两种方法制备热控涂层。第一种利用复合盐封孔制备阳极氧化膜热控涂层,用正交实验研究制备低比值αs/εH的复合盐封孔的热控涂层工艺,同时比较复合盐封孔、镍盐封孔和沸水封孔的耐蚀性。第二种则是电沉积二氧化硅制备热控涂层,用动电位极化曲线研究了铝合金氧化膜表面电沉积二氧化硅工艺,并且利用Box-Behnken实验优化制备低比值αs/εH热控涂层的工艺,同时进行腐蚀加速试验研究二氧化硅热控涂层的耐蚀性。研究表明制备低比值的αs/εH热控涂层的氧化最佳工艺为:电流密度1.0A/dm2,电解液温度18℃,氧化时间30 min,氧化膜表面的粗糙度为0.58,此种工艺制备出的氧化膜的αs/εH比值最小为0.164。制备低比值αs/εH的复合盐封孔的热控涂层工艺:Ca2+浓度为1 g/L,Mg2+浓度为2.0 g/L,络合剂浓度为12 g/L,表面活性剂浓度为0.6 g/L,封孔温度为85℃,封孔时间为35 min,此工艺制备的热控涂层的αs/εH比值达到最低为0.132。电化学分析得出复合盐封孔的效果要明显好于镍盐封孔和沸水封孔,且封孔可以改变氧化膜的αs/εH比值。复合盐封孔的氧化膜表面均匀,其αs/εH比值最小,镍盐封孔降低了氧化膜的孔隙率,沸水封孔的氧化膜表面呈网状结构,不利于制备低比值的αs/εH热控涂层。通过动电位极化曲线研究了电沉积二氧化硅工艺,同时利用响应面软件Design-Expert优化制备热控涂层的工艺。通过响应面分析得到了制备热控涂层的最佳条件:电压4.7 v,pH=3.2,TEOS体积0.19 L,乙醇体积0.6 L,所得的二氧化硅热控涂层的αs/εH比值最小为0.108。腐蚀加速试验表明二氧化硅热控涂层能够阻止腐蚀介质进入氧化膜表面,有效的保护基体免受腐蚀。从耐蚀性和制备低比值的αs/εH热控涂层分析可知:电沉积二氧化硅涂层的耐蚀性优于复合盐封孔制备的热控涂层,且电沉积二氧化硅热控涂层的αs/εH比值最小为0.108。
[Abstract]:In this paper, the anodic oxidation of aluminum alloy and the preparation of thermal control coating by electrodeposition of silicon dioxide were studied. The effect of anodic oxidation process on the optical properties of 伪 s / 蔚 H was studied. The anodizing process of low ratio 伪 s / 蔚 H thermal control coating was determined, and the anodic oxidation process of low ratio 伪 s / 蔚 H was prepared. The thermal control coating was prepared by two methods. Firstly, the thermal control coating of anodic oxide film was prepared by using compound salt to seal holes, and the thermal control coating with low ratio of 伪 s / 蔚 H was prepared by orthogonal experiment. At the same time, the corrosion resistance of composite salt sealing, nickel salt sealing and boiling water sealing was compared. The second was electrodeposition of silicon dioxide to prepare thermal control coating. The electrodeposition process of silicon dioxide on the surface of aluminum alloy oxide film was studied by potentiodynamic polarization curve, and the process of preparing low ratio 伪 s / 蔚 H thermal control coating was optimized by Box-Behnken experiment. At the same time, the corrosion resistance of SiO2 thermal control coating was studied by accelerated corrosion test. The results showed that the best oxidation process of 伪 s / 蔚 H thermal control coating with low ratio was as follows: current density 1.0 A / dm2. The surface roughness of the oxide film was 0.58 when the electrolyte temperature was 18 鈩，

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