电解液组成对镁合金阳极氧化膜性能的影响

阳极氧化处理是提高镁合金耐腐蚀性能的有效方法。在阳极氧化工艺中,电解液组成对镁合金氧化膜的性能有着至关重要的影响。本文概述了近年来该领域内有关电解液组成的研究进展,期望为镁合金阳极氧化工艺研究提供参考。     

己二酸铵对7075-T6铝合金硫酸阳极氧化的影响

研究硫酸电解液中添加己二酸铵对7075-T6铝合金阳极氧化的影响,采用场发射扫描电子显微镜(FE-SEM)对7075-T6铝合金在不添加和添加己二酸铵的硫酸电解液中制备的阳极氧化膜表面的微观形貌进行分析,采用线性阳极极化研究7075-T6铝合金在两种电解液中的极化行为。利用动电位极化技术和电化学阻抗谱(EIS)研究两种电解液中制备的阳极氧化膜的耐腐蚀性能。结果表明:硫酸电解液中添加己二酸铵可以通过降低电流密度来改善氧化膜的结构,减少氧化膜缺陷,降低微孔孔径,提高阻挡层厚度,从而降低氧化膜的自腐蚀电流密度,提高氧化膜耐腐蚀性能。     

氨基酸类有机添加剂对镁合金阳极氧化的影响及其作用机制研究

为了进一步改善镁合金表面阳极氧化膜的质量和性能,在Na OH+Na_2SiO_3基础电解液中添加氨基酸类有机添加剂对AZ31镁合金进行阳极氧化,研究了氨基酸类有机添加剂对镁合金阳极氧化过程及氧化膜厚度、表面形貌、结构及耐蚀性的影响。探讨了有机添加剂在镁合金阳极氧化中的作用机制。结果表明:不同的氨基酸对镁合金阳极氧化过程及氧化膜性能影响不尽相同,其中乙二胺四乙酸和L-鸟氨酸醋酸盐可显著提高阳极氧化的击穿电压,起到明显的抑弧作用,大幅度提高了氧化膜的厚度、致密性和耐蚀性能。有机添加剂主要通过缓蚀、抑弧和表面活性剂3方面的综合作用来影响镁合金阳极氧化的过程及氧化膜的性能。     

电镀Al-Mn合金及后续阳极氧化对镁合金防护性能的影响

为提高镁合金的耐腐蚀性能,采用无机熔盐电镀技术在镁合金表面电镀铝锰合金,其后在草酸溶液中对铝锰合金镀层进行阳极氧化处理,以制备耐蚀性优良的阳极氧化膜。采用扫描电镜(SEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)等对阳极氧化膜的微结构进行表征,采用电化学测试方法对阳极氧化膜的耐腐蚀性能进行评价。结果表明,Al-Mn合金镀层在草酸溶液中形成的阳极氧化膜主要由稳态的α-Al2O3和亚稳态的γ-Al2O3所组成,并含有少量的MnO2及Al(MnO4)3,该阳极氧化膜具有很强的绝缘特性,其腐蚀电流密度较Al-Mn合金镀层下降了约3个数量级,较基体镁合金下降了约6个数量级,极大地提高了镁合金的耐腐蚀性。     

A231镁合金表面阳极氧化工艺研究

采用正交设计方法,研究了AZ31镁合金表面阳极氧化工艺配方.采用扫描电镜(SEM)、能谱分析仪(EDS)、X射线衍射法(XRD)、动电位极化曲线测量方法评价了优化工艺配方条件下阳极氧化膜的微观成分结构及其耐蚀性能.结果表明:经优化配方阳极氧化处理可以显著改善AZ31镁合金的耐腐蚀性能,且经沸水封孔处理可以有效地封闭氧化膜中的裂纹,进一步提高膜层的耐腐蚀性能.     

有机胺对镁合金阳极氧化的影响

以NH4H2PO4、NaF和NaOH组成基础电解液, 采用有机胺作为抑弧剂, 对AZ91D镁合金高压阳极氧化过程进行了研究.结果表明: 有机胺对镁合金的阳极氧化有着显著的抑弧效应, 可使镁合金的阳极火花放电电压提高50～80V.在抑制阳极发生弧光放电的状态下, 镁合金表面可以沉积一层致密、具有较高硬度和优良耐蚀性能的氧化膜层.分析了有机胺对氧化膜层性能和表面形貌的影响以及不同有机胺在镁合金阳极氧化过程中的抑弧能力, 并初步探讨了有机胺在镁合金阳极氧化过程中的抑弧机理.     

交流电压对AZ91D镁合金阳极氧化膜层的影响

在含有硅酸钠和硅溶胶的氧化溶液体系中,利用工频交流电源对AZ91D镁合金材料表面进行阳极氧化处理,同时探讨氧化电压对膜层表面形貌、生长速率和耐腐蚀性能等的影响规律.结果表明:氧化过程存在一个明显的临界电压值(170 V),在电压大于170V阳极氧化反应剧烈、氧化电流增大、试样表面出现弧光放电.当电压小于170 V时,镁合金表面则以均匀的桔黄色火花放电,获得的氧化膜层表面光滑、均匀、致密,而且膜层的生长速率和耐腐蚀性随着电压的增加而增大;当电压超过这个临界电压值时,获得的氧化膜层表面变得粗糙,其生长速率大幅提高,但膜层的耐腐蚀性能下降.     

镁合金环保型阳极氧化工艺研究

通过环保型阳极氧化工艺在MB2镁合金表面获得了表面质量良好的银灰色氧化膜层,用金相显微硬度计、扫描电镜和X射线衍射等表面分析手段,研究了氧化膜层的显微硬度、截面形貌和相结构,并采用动电位扫描的电化学方法考察了氧化膜的耐腐蚀性能.结果表明：氧化膜层的主要成分为MgO、MgAl2O4、Al2O3;膜层具有多孔结构,孔径较为均匀,分为内外两层,外层为疏松层,内层为与基体结合牢固的致密层;阳极氧化电流密度和电解液中铝盐浓度是影响阳极氧化膜层性能的主要因素;所得膜层的显微硬度值高达558.4 HV,同时其耐蚀性能也远优于传统含铬DOW17工艺所成的防护膜,且所用电解液无铬无磷更为环保经济.     

镁合金阳极氧化的研究进展与展望

回顾镁合金阳极氧化历史，介绍制备工艺、电解液组成及作用，同时对镁合金阳极氧化机理进行探讨。随着人类环保意识的增强，世界能源的紧缺和氧化设备的不断更新，认为电参数如频率、占空比、电压和电流密度对氧化膜性能的影响、阳极氧化电流效率的测定、氧化膜扩散规律的研究和环保型电解液的开发为未来镁合金阳极氧化研究的重点。     

阳极氧化对AZ31镁合金表面粘接性能的影响

为了提高AZ31镁合金表面与有机涂料和胶粘剂的粘接强度,通过对镁合金表面进行阳极氧化处理的方法,利用正交试验对镁合金硅酸盐阳极氧化电解液配方和工艺进行了优化,研究了其对氧化膜粘接性能的影响.得出不同工艺参数对粘接强度的影响程度从小到大排列为:KF浓度＜Na2B4O7浓度＜KOH浓度＜阳极氧化时间＜电流密度.所得氧化膜的表面电位比基体提高了200mV,粘接强度提高了约50%.结果表明:氧化膜的表面形貌对粘接强度起决定性影响,表面成分则影响不大.     

工艺参数对Al合金阳极氧化膜腐蚀行为的影响

用电化学极化和扫描电镜(SEM)观察法,研究了电流密 度、氧化时间和氧化温度等工艺参数对LC4铝合金阳极氧化膜的厚度、显微形貌和在NaCl溶 液中耐蚀性的影响，讨论了影响氧化膜耐蚀性的机制，提出了提高耐蚀性的最佳阳极氧化工 艺参数.     

Environmental friendly anodizing of AZ91D magnesium alloy in alkaline borate-benzoate electrolyte

A kind of environmental friendly anodizing routine for AZ91D magnesium alloy, based on an alkaline borate-sodium benzoate electrolyte (NaBz) was studied. The effect of NaBz on the properties of the anodized film was investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometry (EDS), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS), respectively. The results showed that the anodizing process, surface morphology, thickness, phase structure and corrosion resistance of the anodized film were strongly dependent on the concentration of NaBz. In the presence of adequate NaBz, a thick, compact and smoothing anodized film with excellent corrosion resistance was produced. Moreover, the forming mechanism of the anodized film in the presence of NaBz additive was also approached, which was a suppression of arc discharge process by the adsorption of Bz⁻ on the surface of magnesium alloy substrate.     

铝合金型材阳极氧化膜的滴碱与落砂试验

通过试验，研究了合金成分、常温封孔、阳极氧化工艺条件对氧化膜耐蚀性，耐磨性的影响；讨论了这些因素对氧化膜耐蚀性、耐磨性的影响机理，指出了为保证氧化膜的耐蚀性、耐磨性而采取的工艺措施。     

Pure Commercial Titanium Color Anodizing and Corrosion Resistance

In order to improve titanium corrosion behavior, we can increase the thickness of oxide layer on titanium surface during anodizing process and by electrochemistry. In this research, self-color anodizing of Ti in sulfuric acid was done, and anodizing layers were created in different colors. The highest value of chromaticity was 37.8 for the anodized sample in 10 V, and the lowest value was 8.6 at 15 V. The oxide layer thickness was calculated by optical method (light refraction). The anodic film thickness increased by increasing the anodizing voltage. The highest thickness of anodic film was 190 nm in sulfuric acid solution for the anodized sample in 80 V. Corrosion resistance of anodized Ti was studied by potentiodynamic polarization curves in biological solution of Ringer’s at 37 °C. On increasing the anodizing voltage further, corrosion rate of the alloy increased from its lowest rate. The lowest rate of corrosion was for the sample anodized in 10 V, which was 0.96 × 10⁻³ mpy.     

2024铝合金混合酸阳极氧化

目的在混合酸溶液中,对2024铝合金进行不同条件下的阳极氧化,并制备氧化膜,研究比较氧化膜厚度、表面形貌和耐腐蚀性等的不同。方法 2024铝合金在硫酸-磺基水杨酸-乳酸体系中进行阳极氧化,改变氧化时间(20~60 min)与氧化电流密度(2.5~4.5 A/dm^2),观察氧化膜的表面形貌、显微硬度、厚度、晶体结构以及耐蚀性的变化。结果每次实验的氧化时间为40 min不变,改变电流密度得到一系列阳极氧化膜,当电流密度为3.0 A/dm^2,自腐蚀电位最正,接近0.0 V时膜层的耐蚀性最好。若继续增加电流密度,则自腐蚀电位会负向移动。当电流密度为4.5 A/dm^2时,自腐蚀电位最负,为-1.1 V。保持电流密度为2.5 A/cm^2不变,改变氧化时间,得到一系列阳极氧化膜,当氧化时间达到50 min时,氧化膜的耐腐蚀性最好,自腐蚀电位为-0.6 V。XRD分析表明,氧化膜由γ-Al2O3和α-Al2O3组成。氧化膜的显微硬度和厚度会随着电流密度及时间的增加而增大,氧化膜硬度、厚度最大分别为372.3HV、6.8μm。结论当阳极氧化电流密度为3.0 A/d、氧化时间为50 min时,膜层的耐蚀性最好。     

Anodization of AZ91 magnesium alloy in alkaline solution containing silicate and corrosion properties of anodized films

The anodization of AZ91 magnesium alloy in an alkaline electrolyte of 100g/L NaOH 20g/L Na2B4O7·10H2O 50g/L C6H5Na3O7·2H2O 60g/L Na2SiO3·9H2O was studied.The corrosion resistance of the anodized films was studied by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques.The microstructure of the films was examined with scanning electronic microscope (SEM) and X-ray diffractometer (XRD).The results show that,under the experimental conditions,the optimum anodizing time and the optimum anodizing current density are 40min and 20mA/cm2 respectively for obtaining the anodic film with high corrosion resistance.The XRD pattern shows that the components of the anodized film consist of MgO and Mg2 (SiO4).     

Corrosion Behavior of Anodized Al Coated by Physical Vapor Deposition Method on Cu–10Al–13Mn Shape Memory Alloy

Physical vapor deposition method was utilized to apply Al coating onto Cu–10Al–13Mn alloy, then coated layer was anodized in different temperatures: 5 and 10°C as well as several potentials: 20, 30, 40, 50 V in order to achieve best anodizing parameters. The effects of anodizing parameters on alumina nanotube formation and corrosion resistance were investigated. Phase analysis on surface was conducted by X-ray diffraction method and nanotube characteristics was studied by scanning electron microscopy (SEM) and surface topology was investigated by atomic force microscopy (AFM). Additionally, the corrosion resistance of coatings was studied by potentiodynamic test in 1M NaCl solution. The results depicted that whole deposited Al layer was anodized and FCC alumina was formed merely. Polarization test results was illustrated that Al anodized layer significantly improved Cu–10Al–13Mn corrosion resistance. Uncoated specimen had highest corrosion rate and anodized layer in lower temperature and voltage had minimum alumina nanotube dimension; as a result, it had best corrosion behavior in NaCl corrosive solution.     

Evaluation of different sealing methods for anodized aluminum‐silicon carbide (Al/SiC) composites using EIS and SEM techniques

Electrochemical impedance spectroscopy (EIS) and the scanning electron microscope (SEM) have been used in an investigation of the effectiveness of various sealing methods that can be used to improve the corrosion resistance of an anodized aluminum‐silicon carbide (Al/SiC) composite. Anodic oxide films were grown on Al7075‐T6 and the Al/SiC composite by sulfuric acid anodizing and sealing in a cold saturated solution of nickel acetate. Other samples were sealed using the traditional method of boiling water or hot nickel acetate for comparison. The results revealed a uniform anodized layer on Al7075‐T6 that resisted pitting corrosion for more than 2 weeks exposure to NaCl, whereas a cracked oxide film with variations in thickness was observed on the composite material. Pit initiation occurred in less than 5 days on the anodized Al/SiC that was sealed in the hot solutions. This study suggests that the traditional hot sealing methods did not provide sufficient corrosion protection for aluminum metal–matrix composites (MMCs) because the reinforcing SiC particles deteriorated the surface film structure. However, this defective film can be repaired by nickel hydrate precipitation during cold sealing or by applying a thick polyurethane coating.     

Corrosion Resistance and Color Properties of Anodized Ti-6Al-4V

In this research, color anodizing of Ti-6Al-4V alloy was performed in phosphoric acid solution of 0.4 M concentration and within 30 s in different voltages (10-120 V) of a DC power supply. The effect of anodizing voltages on the color and thickness of anodized layers on Ti-6Al-4V alloy surface was surveyed. Thickness and refractive index of layers were measured by spectrophotometery and reflectance curves. According to the results, thickness of layers increased with increasing anodizing voltage and was in the range of 38-167 nm. Also the refractive index of anodic film was approximately constant at about 2 and increased inconsiderably with increasing anodizing voltage. Corrosion resistance of the anodized samples in 20 and 50 V was surveyed in physiological solutions of Ringer’s solution, Artificial Saliva solution, and Ringer’s + 150 mM H₂O₂ solution at the temperature of 37 °C by potentiodynamic polarization method. The anodized sample in 50 V indicated lower corrosion rate than the non-anodized sample as well as the sample which was anodized in 20 V in all solutions. The non-anodized sample indicated the highest corrosion rate of about 0.25 μA cm⁻².