交流扩孔对铝氧化膜电解着色的影响

研究了磷酸溶液交流扩孔对铝阳极氧化膜电解着色的影响。结果表明,磷酸交流扩孔后氧化膜的电解着色性能发生了明显变化。改变交流扩孔的工艺条件,可获得黄色、灰色、绿色、古铜色、蓝色等多种色调的氧化膜。扫描电镜照片显示,经磷酸溶液交流扩孔后,多孔氧化膜孔径可增大一倍以上,电解着色并未引起膜表面微观形貌的明显变化。所得最佳扩孔工艺条件为:磷酸90~110g/L,电流密度1.5~1.75A/dm2,电压5~10V,时间8~12min,温度20~30°C。     

铝合金阳极氧化-交流电解着色膜对可见光的吸收性能

先采用165 g/L硫酸溶液在温度(20±1)°C、电流密度1.5 A/dm²和电压15 V的条件下对1235铝合金阳极氧化30 min,再采用由15 g/L Cu SO₄·5H₂O、2.5 g/L Mg SO₄·7H₂O和25 g/L H₃BO₃组成的电解液,在室温、电压12 V和电流密度1.3 A/dm²的条件下交流电解着色30～360 s。研究了着色时间对膜层颜色、铜沉积量和吸光度的影响。结果表明,随电解着色时间延长,铜的沉积量增大,膜层颜色变深;膜层颜色与铜的特征吸收有关,但铜粒子对光的散射才是决定氧化膜颜色的主要因素。     

铝氧化膜电解着色研究

本文根据已提出的电极等效电路模型,通过测量不同电解着色条件下产生的着色膜的交流阻抗,讨论阳极氧化电解液组成和电压;电解着色电压;着色电解液;着色电源波形和着色时间等条件对膜的等效电路参数值的影响,以及这些参数的改变与氧化膜结构和性能的关系。实验结果可为工艺条件的选择提供依据。     

铝的草酸低压阳极氧化膜的电解着色

众所周知,常规的草酸阳极氧化膜(氧化电压为50～60伏)不能在NiSO_4溶液中电解着色.事实上,在任何电压(电解着色电压)都不上色.大约在35伏交流电压便使膜击穿,产生所谓"剥落".也就是说,镍不能沉积在氧化膜的微孔中.然而,实验发现:低阳极氧化电压(直流7～8伏)形成的草酸阳极氧化膜着色均匀并呈现深古铜色.此外,1微米以下的薄氧化膜能全着色.例如:能得到蓝、黄、绿和紫红等色.3微米以上的厚膜着色呈古铜色.白光照射到全着色膜时,入射光在电镀镍针的针尖和微孔底部(金属界面)产生反射,两股反射光都发生干涉,随着镍针的上升,可以看出各种颜色的干涉光束.在此情况下,不仅阻挡层、多孔层的厚度,而且在微孔中镍针高度的一致性都是非常重要的.根据光学理论,镍针高度约为可见光波长的四分之一.     

铝合金直流电阳极氧化膜电解着色的研究

以工业纯铝L2为实验材料,采用硫酸直流电阳极氧化-电解着色工艺在铝合金表面制备黑色膜层.着重分析着色电压对黑色膜层表观颜色、厚度、硬度的影响.通过SEM表征、EDS测试及性能测试表明:在优化后的电解着色工艺条件下可以获得与工业纯铝L2基体结合力良好,且耐蚀性、耐热性、吸光性均较好的黑色膜层.     

镍—锌双盐溶液铝电解着色：用微分李沙育法的研究结果

用微分李沙育法考察了铝及铝合金阳极氧化膜在Ni-Zn盐电解着色液中的交流电解着色过程,研究了电解着色时间、电压、着色液中镍、锌盐的浓度及铝基体材料对电解着色阳极电流密度的影响.     

铝阳极氧化着色工艺的研究

分别采用草酸、硼酸和磺基水杨酸为主盐的复合电解液对铝进行阳极氧化着色研究,结果表明:当电压控制在50～60V,溶液温度20～60℃时,可在铝表面形成一层黄色、灰色或香槟色系的阳极氧化膜,氧化膜具有优异的耐蚀性能;电解液组成、阳极氧化峰值电流以及溶液搅拌强度对氧化过程和氧化膜的性能会产生明显影响.     

阳极氧化铝在锡盐溶液中电解着色的机理

当前,国内多数采用锡盐溶液电解着色阳极氧化铝,但对其着色机理却研究很少。本文研究影响电解着色的某些因素,测量着色膜的阻抗,分析膜中锡含量的分布,从而探讨了在锡盐溶液中氧化铝膜着色的机理。在交流电压上迭加直流电压,不仅对电解着色的效果有明显影响,而且有助于弄清楚着色的机理。     

铜的电解着色

铜的着色有化学法和电化学法二种,目前大多采用化学处理方法,也有采用阳极电解氧化法。本文提出采用阴极电解还原的方法,在阴极上形成氧化亚铜膜,从而获得所需色调。其电解着色液的配方及工作条件为:CuSO_4·5 H_2O 30～60g/L,柠檬酸三钠60～120g/L,乳酸80～140ml/L,NaOH80～120g/L,D_K 5～40mA/dm~2,电压0.05～0.35伏,温度为室温。文内还对各种因素的影响,如成份、电流密度、温度和电极的影响进行了探讨,并提出了对着色层性能的检测方法和不合格着色层的退除方法。结论是该电解着色液稳定性好、寿命长,适合于连续操作,着色层光亮、均匀,且有一定的抗蚀耐磨性能。     

氧化电压对钛合金彩色阳极氧化膜性能的影响

为了研究氧化电压对钛合金阳极氧化膜颜色及性能的影响,采用硫酸-磷酸的复合电解液体系和单脉冲供电方式,在不同氧化电压下制备了阳极氧化膜。利用场发射扫描电镜观察氧化膜的微观形貌变化,采用显微硬度计、表面粗糙度仪、接触角测量仪分别测量膜层的硬度、粗糙度及接触角,利用电化学工作站分析各膜层的耐蚀性能。结果表明：氧化膜的颜色在45 V时为黄色,50～60 V时为紫色,70 V时为浅蓝色,75 V时为绿色。当氧化电压为65 V时,氧化膜为蓝色,氧化膜粗糙度为0.939μm,硬度为361.6 HV_0.2,接触角为89.2°,自腐蚀电流密度为2.004×10^-7A·cm^-2,耐蚀性较好。     

Kinetics of the electrolytic coloring process on anodized aluminum

The kinetics of tin electrodeposition during the electrolytic coloring of porous anodic oxide films on aluminum is studied as a function of the oxide properties, e.g., the thickness of the porous oxide layer, and the surface resistance offered by the barrier oxide layer. While the thickness of the porous oxide layer is controlled by the anodization time, the surface resistance is controlled by the anodization voltage, and the anodization bath temperature. Steady-state polarization measurements are employed to characterize the dependence of the coloring kinetics on the oxide properties. Measurements indicate that the kinetics of the electrolytic coloring process can be accelerated by: (i) reducing the surface resistance of the oxide film (primarily offered by the barrier oxide layer) by growing the oxide at a lower anodization voltage, and/or a higher bath temperature, or (ii) growing a thinner porous oxide layer by decreasing the anodization time. The electrochemical measurements are supported by gravimetric analysis of electrolytically colored alumina samples (using calibrated wavelength-dispersive X-ray fluorescence spectroscopy), and by optical spectrophotometry.     

电压对7N01铝合金阳极氧化膜结构及耐蚀性的影响

采用160 g/L硫酸溶液在17℃下对7N01铝合金阳极氧化30 min,氧化电压分别选取14、15、16、17和18 V。用扫描电镜观察所得阳极氧化膜的形貌,用能谱仪和电化学测量分析了它的成分、厚度和耐蚀性。结果表明,7N01铝合金经过不同电压下的阳极氧化处理后,表面均能形成凹凸不平并有孔洞的阳极氧化膜,电压为17 V时所制膜层致密、均匀,厚度约为7.6μm,耐蚀性最佳,在3.5%NaCl溶液中浸泡1 440 h后没有明显的腐蚀。     

Effects of alternating and direct current in electrocoagulation process on the removal of fluoride from water

BACKGROUND: When direct current (DC) is used in electrocoagulation processes, an impermeable oxide layer may form on the cathode and corrosion of the anode may occur due to oxidation. This prevents effective current transfer between the anode and cathode, so the efficiency of the electrocoagulation process declines. These disadvantages of DC have been reduced by adopting alternating current (AC). The main objective of this study is to investigate the effects of AC and DC on the removal of fluoride from water using an aluminum alloy as anode and cathode. RESULTS: Results showed that removal efficiencies of 93 and 91.5% with energy consumption of 1.883 and 2.541 kWh kL^?1 was achieved at a current density of 1.0 A dm^?2 and pH 7.0 using an aluminum alloy as electrodes using AC and DC, respectively. For both AC and DC, the adsorption of fluoride fitted the Langmuir adsorption isotherm. The adsorption process follows second‐order kinetics and temperature studies showed that adsorption was exothermic and spontaneous in nature. CONCLUSIONS: The aluminum hydroxide generated in the cell removed the fluoride present in the water and reduced it to a permissible level thus making it drinkable. It is concluded that an alternating current prevents passivation of the aluminum anode during electrocoagulation and avoids the additional energy wasted due to the resistance of the aluminum oxide film formed on the anode surface. Copyright © 2010 Society of Chemical Industry     

The Influence of Ti-6AI-4V Chromic Acid Anodization Conditions Upon Anodic Oxide Thickness and Topography

Chromic acid (CA) anodization of Ti-6A1-4V (6% Al, 4% V by weight) produced an anodic oxide on the alloy surface. The influence of specific CA anodization conditions upon anodic oxide thickness was determined. Each CA anodization condition tested was defined by setting five variables: (1) solution composition; (2) anodization time; (3) solution temperature; (4) initial current density; and, (5) anodization potential.

The results confirmed observations by previous workers about oxide thickness and structure. Data indicated an inverse relationship between film thickness and temperature, and that film growth rate decreases with time.     

铝及铝合金阳极氧化膜着色技术研究进展

较系统地评述了近年来铝及铝合金材料在表面着色方面的研究进展,主要介绍了国内外广泛应用的交流电解着色技术（简称电解着色法）,电解着色法按其发色特点,可分为自然发色法、一步电解着色法、二步电解着色法和三次多色电解着色法等等。其中,三次多色电解着色法是当前最先进的电解着色技术,此外,还介绍了近年来成为研究热点和进入工业生产应用的微孤氧化陶瓷成膜技术。     

镁合金交流电氧化工艺研究

在氢氧化钠、硼酸盐、硅酸盐及有机胺的混合溶液中,用普通交流电对AZ91D镁合金进行电解氧化。研究了溶液组成、氧化电压、温度和时间等对镁合金电解氧化的影响。最佳工艺条件为:30g/LNaOH,25g/LNa2B4O7,50g/LNa2SiO3,40mL/L三乙醇胺,交流电压130～160V,时间10min。在最佳工艺条件下,镁合金表面形成了一层致密光滑的类陶瓷膜层,该膜层具有良好的耐蚀性能。     

Modeling of the Current Distribution in Aluminum Anodization

The growth of porous anodic Al₂O₃ films, formed potentiostatically in continuously stirred 15 wt.% H₂SO₄ electrolyte was studied as a function of the anodization voltage (14–18 V), bath temperature (15–25 °C) and anodization time (15–35 min). The variation of the anodic surface overpotential with the current density was measured experimentally. The film thickness at the more accessible portions of the anode was observed to increase with the anodization voltage and the bath temperature. However, the film thickness on the less accessible portions of the anode did not significantly change with the voltage or the bath temperature. This indicates that the anodization process at the more accessible regions is more strongly influenced by the surface processes than by the electric migration within the electrolyte. Furthermore, analysis confirms that the major portion of the film resistivity resides within a thin sub-layer that does not vary with the anodization time, and the growing anodic layer contributes only marginally to the overall film resistance. Computer aided design software was employed to simulate the current density distribution. For the range of process parameters studied, the electrochemical CAD software predicts accurately the measured thickness distribution along the anode.     

硫酸电解液中铝合金硬质阳极氧化膜的表面形貌及性能研究

在硫酸电解液中采用硬质阳极氧化技术对铝合金进行了表面处理,并研究了电流密度对阳极氧化膜性能的影响。结果表明:当电流密度为1.5 A/dm²时,阳极氧化膜表面最光滑,显微硬度最大,自腐蚀电位最正。当电流密度为2.0 A/dm²时,交流阻抗曲线的弧度最大。可见,当电流密度为1.5～2.0 A/dm²时,阳极氧化膜的耐蚀性较好。     

铝阳极氧化膜在SeO_3~(2-)溶液中电解着色

铝阳极氧化膜在SeO_3~(2-)溶液中电解着色时在一定工艺条件下出现饱和色。增加着色电压、电流及槽液中SeO_3~(2-)浓度均不能加深饱和色;而改变槽液温度、活化条件可改变饱和色,但最深色调为桔红色。若在SeO_3~(2-)着色液中添加Cu~(2+)不再显示饱和色,可得到从浅黄到灰色等着色膜。通过分析膜层中Se及Cu含量,说明了Cu与Se发生了共沉积。