硫酸阳极氧化对7A65航空铝合金疲劳性能的影响

[目的]铝合金零件的疲劳性能是决定飞机服役寿命的关键因素。硫酸阳极氧化是铝合金零件常用的表面处理工艺,研究其对铝合金疲劳性能的影响对指导生产极其重要。[方法]针对新型航空铝合金7A65,采用重复退膜-阳极氧化的方式开展实验。通过疲劳试验机对试样进行疲劳性能测试,绘制应力-疲劳寿命曲线,分析和对比重复退膜和阳极氧化不同次数后7A65铝合金的疲劳性能。通过体视显微镜和扫描电子显微镜对典型断口形貌进行分析,并探讨了其疲劳失效机制。[结果]7A65铝合金在重复退膜-阳极氧化处理后疲劳极限明显下降。经过2次阳极氧化,7A65铝合金的疲劳极限下降为原疲劳极限的61.1%;继续进行退膜-阳极氧化处理,疲劳极限下降趋缓,4次阳极氧化后的疲劳极限为原疲劳极限的56.5%。在此过程中,其疲劳断口呈现出由单一裂纹源向多裂纹源,以及从韧性断裂向脆性断裂的转变。[结论]硫酸阳极氧化对7A65铝合金疲劳性能的影响较大,在生产中应当控制阳极氧化零件的返修次数。     

铝合金硫酸阳极氧化常见质量问题探究

铝合金材料在航空航天领域中应用广泛,硫酸阳极氧化可以提高其耐腐蚀性能。以不同温度对硫酸阳极氧化膜层进行冲击,证明了高温环境会降低硫酸阳极氧化膜层的耐腐蚀性能,并对其原因进行了剖析;从材料机械成型加工过程、硫酸阳极氧化工艺过程分析了膜层表面"黑点"的形成原因,并对其解决方法进行了探究;阐述了铝合金材料状态对硫酸阳极氧化膜层质量性能的影响。     

2060铝锂合金在3种溶液体系中所得阳极氧化膜层的性能

分别采用硼硫酸(45.0 g/L硫酸+8.0 g/L硼酸)、硫酸(160.0 g/L硫酸)和混酸(140.0 g/L硫酸+20.0 g/L草酸+50.0 g/L酒石酸钾钠+1.5 g/L添加剂)这3种溶液体系在2060铝锂合金上制备阳极氧化膜,考察了电流或电压对所得膜层性能的影响。用金相法测量了氧化膜的厚度,用扫描电镜观察了氧化膜的微观形貌。通过静力拉伸及拉-拉疲劳试验测试了阳极氧化前后铝锂合金的力学性能。通过观察疲劳断口的形貌,分析了阳极氧化工艺影响铝锂合金疲劳性能的原因。2060铝锂合金在3种体系中均能形成颜色均一、表面光滑的阳极氧化膜。在硼硫酸体系中得到的阳极氧化膜厚度不足2μm,在硫酸和混酸体系中得到的阳极氧化膜的厚度可达15μm。阳极氧化工艺显著提升了铝锂合金的耐蚀性,在混酸、硫酸和硼硫酸体系中得到的阳极氧化膜的耐中性盐雾时间依次为870、378和87 h,远超纯铝锂合金的8 h。但是,混酸阳极氧化工艺使2060铝锂合金的抗拉强度和屈服强度下降了至少9%,在应力比0.06、应力水平240 MPa之下的中值疲劳寿命降低了90%。     

磷酸–硫酸阳极氧化对铝合金表面粘接性能的影响

研究了磷酸–硫酸阳极氧化对铝合金2A50表面粘接性能的影响,并与喷砂处理进行比较。阳极氧化液组成与工艺条件为:磷酸70g/L,硫酸50g/L,草酸7g/L,甘油20g/L,温度(22±2)℃,电压20V,时间35min。采用扫描电镜观察经阳极氧化处理和经喷砂处理的铝合金表面、粘接界面、破坏界面的微观形貌,利用能谱仪分析阳极氧化膜的组成。结果表明,磷酸–硫酸阳极氧化可明显提高铝合金粘接副的拉伸剪切强度和粘接耐久性能。分析了磷酸–硫酸阳极氧化的成膜特点及电解液主要成分的作用,解释了阳极氧化处理后铝合金的粘接性能优于喷砂处理的原因。     

7050-T7451铝合金阳极氧化膜在模拟舰载环境下的腐蚀行为及疲劳性能衰减研究

通过酸性盐雾试验研究了经苹果酸?硫酸体系阳极氧化处理的7050-T7451铝合金在模拟舰载环境中的腐蚀行为.通过扫描电子显微镜、电化学阻抗谱测量和疲劳性能测试分析了经酸性盐雾腐蚀不同时间后阳极氧化膜结构和基体疲劳寿命的变化.结果表明,阳极氧化膜对铝合金基体具有很好的保护作用,能够保护铝合金基体在酸性盐雾试验的4个周期(...     

铝合金阳极氧化着黑色热控涂层工艺研究

介绍了一种铝合金阳极氧化着黑色热控涂层工艺,此工艺采用硫酸阳极氧化方法以及深黑32#有机染料着色,对LY12铝合金H112热处理状态材料进行了处理。通过正交试验对氧化时间、氧化温度、电流密度工艺参数进行优化,得到高发射率的最佳工艺参数。     

铬酸阳极化和化学氧化处理对铝合金疲劳性能影响研究

通过对铬酸阳极化和化学氧化处理后的铝合金试板进行疲劳试验,研究两项表面处理工艺对铝合金疲劳性能的影响。     

表面处理工艺对铝合金防腐涂层性能影响研究

通过拉开法附着力测试、耐海水浸泡试验及电化学阻抗试验等方法,研究了铝合金不同表面处理工艺对防腐涂层耐蚀性能的影响。研究结果表明:打磨和钝化处理能大幅提高防腐涂层的附着力,附着力可达16~20 MPa,但涂层的模拟电阻值较低,海水浸泡5个月后,仅为(0.8~1.3)×108Ω;阳极氧化处理基材表面防腐涂层的附着力较低,仅为9 MPa,但基材的耐蚀性能有大幅提高,海水浸泡5个月后,涂层模拟电阻值仍可达(1.0~1.3)×109Ω。以上研究结果可为铝合金基材表面处理工艺的选择提供参考依据。     

影响铝合金阳极氧化热控膜热物理性能的因素

通过硫酸阳极氧化在3A21铝合金表面制备了阳极氧化膜。考察了溶液温度、电流密度、氧化膜厚度、真空钎焊、化学抛光对氧化铝涂层的半球发射率ε_H和太阳吸收比α_s的影响,并测试了氧化铝涂层的稳定性和抗原子氧能力。采用合适的工艺方法可获得具有特定热物理性能的氧化铝涂层,满足卫星有效载荷热控涂层的要求。     

排球挂钩用铝合金基材阳极氧化处理及耐蚀性研究

使用铝合金挂钩对装入网兜的排球进行悬挂和管理,具有取用方便、节约空间、美观等优点。使用硫酸阳极氧化技术对排球挂钩用5005铝合金基材进行了处理,并对阳极氧化膜的性能进行了研究。结果表明:阳极氧化膜主要由铝、氧、硫、碳元素构成,其中铝和氧的总质量分数超过80%,少量的硫来自硫酸。经过硫酸阳极氧化处理后,铝合金表面形成高硬度和高熔点的a-Al2O3和y-Al2O3,大大提高了铝合金的硬度。阳极氧化膜由高电阻的阻拦层和多孔层构成,可以有效地分散和降低自腐蚀电流密度,大大提高铝合金基材的耐蚀性。     

Polypyrrole electropolymerized on aluminum alloy 1100 doped with oxalate and tungstate anions

Polypyrrole films doped with oxalic acid and tungstate were potentiostatically electropolymerized on aluminum alloy 1100. Two statistical factorial designs (fractional and complete) were used to study the influence of the synthesis variables on the film performance against corrosion. Corrosion protection of the polypyrrole films doped with oxalate and tungstate anions (PPy/OXA/W) on the aluminum alloy was evaluated by potentiometric and electrochemical impedance spectroscopy (EIS) measurements in a 0.05 mol L⁻¹ NaCl solution. The results obtained showed that the best performance against corrosion was detected with the PPy/OXA/W film synthesized at 1.0 V, 1.5 C in 0.2 mol L⁻¹ pyrrole, 0.1 mol L⁻¹ oxalic acid and 0.05 mol L⁻¹ sodium tungstate solutions provide a protective effect against corrosion.     

环氧浇铸料及其玻璃钢热性能与内应力

研究了塑料/铸铝复合模具用环氧浇铸料及其玻璃钢热性能及内应力,探讨了塑料配方对浇铸料固化收缩率、力学性能、热膨胀性能及塑料/铝复合板经热处理后的内应力的影响。     

中性介质铝表面无机非金属膜层的电化学沉积Ⅰ无机非金属膜层的制备

在由成膜促进剂、络合成膜剂和某些金属含氧酸盐组成的中性电解液中,对铝进行高压阳极氧化,铝表面可沉积一层具有陶瓷光泽的无机非金属膜层。该膜层具有较高的硬度和耐酸碱性能,膜层颜色随金属含氧酸盐不同而改变。     

The effect of silane layer drying temperature on epoxy coating adhesion on silane-pretreated aluminum substrate

In this study, 3-glycidoxypropiltrimethoxysilane was used as an adhesion promoter to enhance the adhesion strength of epoxy coating on an aluminum (Al) substrate. Silane layer drying temperature was investigated as a factor that has an influence on the adhesion of polymeric coating on metal substrate and also on its performance in wet and corrosive environments. FTIR tests were carried out to study Al/silane interactions. Drying the silane layer at high temperatures formed a condensed siloxane layer that improved the bonding strength as well as the performance of the protective coating in corrosive environments. The highest dry and wet pull-off strengths were obtained at drying temperatures of 100 and 125°C, respectively.     

铝合金内衬复合材料高压容器界面粘结的研究

复合材料高压容器由于其质量轻近年来被广泛应用在航天方面,但是复合材料气密性差,通常用金属内衬来提高其气密性.由于铝合金和复合材料变形不协调,致使铝合金内衬耐疲劳性能很差.界面良好的粘接使铝合金和复合材料形变相协调,能够很好的提高铝合金内衬复合材料高压容器的耐疲劳性能.因此,对复合材料和铝合金界面粘结的研究具有重要的意义.     

铝合金表面耐久性超疏水防护膜的制备与表征

通过酸刻蚀-沸水浴处理构筑微纳米分级结构,进而通过喷涂含有磷酸铝胶黏剂（AP）和低表面能物质——全氟辛基三氯硅烷（PFOTS）的悬浮液增强结合力并降低表面能,从而在国产7B04铝合金表面制备了耐久性超疏水防护膜。利用场发射扫描电子显微镜（FESEM）、X射线光电子能谱仪（XPS）、傅里叶变换红外光谱仪（FTIR）、接触角测试仪（CA）、电化学阻抗谱（EIS）等技术以及多种环境模拟实验对样品进行了表征,结果显示,制备的防护膜表面水静态接触角（WCA）高达158.4°,滑动角（SA）为0°,呈现出超疏水和低黏附性;膜层电阻（R_c）约为101.55 kΩ·cm²,在NaCl腐蚀介质中的电荷转移电阻（R_t）增大了近2个数量级,表现出优异的防护性能;样品可以经受多种破坏,具有理想的机械耐久性、化学耐久性和环境耐久性。     

Preparation and characterization of durable superhydrophobic protective coatings on aluminum alloy

The durable superhydrophobic protective coatings on the 7B04 aluminum alloy surface was prepared by using acid etching and boiling water bath to construct micro-nano hierarchical structure, and then spraying suspension containing aluminum phosphate adhesive (AP) and perfluorooctyltrichlorosilane (PFOTS) to increase adhesion and reduce surface energy. The samples were characterized by field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), contact angle measurement (CA), electrochemical impedance spectroscopy(EIS) and a variety of the environmental simulation experiments. The results showed that the static water contact angle (WCA) of the surface is 158.4° and the slide angle (SA) is about 0°, suggesting superhydrophobicity and low adhesion to water. The coating resistance (R_c) was as high as 101.55 kΩ· cm² and the charge transfer resistance (R_t) in NaCl corrosion medium increased by nearly two orders of magnitude, showing excellent protective performance. The sample can withstand a variety of damages, with ideal mechanical durability, chemical durability and environmental durability.     

Corrosion characteristics of aluminum alloy in bio-ethanol blended gasoline fuel: Part 2. The effects of dissolved oxygen in the fuel

This study examined the effects of dissolved oxygen on the corrosion properties of aluminum cast alloy, A384, in bio-ethanol blended gasoline fuel at 100 °C. Oxygen enhanced the corrosion resistance of the alloy by forming a protective hydrous oxide film. The acetic acid and water produced by ethanol oxidation in the fuel had a corrosive and protective effect, respectively. However, the protective hydrous oxide film enhanced by the water suppressed the corrosiveness of the acetic acid in the fuel when the two by-products coexisted. Therefore, the water formed by dissolved oxygen in the bio-ethanol blended gasoline fuel enhanced the corrosion resistance of the aluminum alloy by promoting the formation of a protective surface film.     

Synthesis and Study of a Polypyrrole–Aluminum Oxide Nanocomposite Film on an Aluminum Surface

Using the method of electrochemical anodization, aluminum oxide porous films are obtained in a sulfuric acid solution. The morphology of the aluminum oxide surface is studied by the method of scanning electron microscopy. The high-quality elemental analysis of the initial and oxidized Al films is performed using the method of electron microprobe analysis. A protective composite polypyrrole-aluminum oxide film is produced on the aluminum surface on top of a porous aluminum oxide film in the galvanostatic oxidation mode by the electrochemical synthesis method. The properties of the polypyrrole–aluminum oxide composite film are studied by the methods of voltammetry, as well as impedance and FTIR spectroscopy.     

分子筛的补铝及其催化性能研究

本文介绍了分子筛的补铝方法及其补铝后分子筛的催化性能。按所用的补铝溶液性质可分为 Na OH等碱性溶液补铝法、Al Cl3 和 HCl酸性溶液补铝法及含羟基有机酸溶液补铝法 ,补铝机理涉及晶格缺陷位补铝、非骨架位表面反应以及同晶取代三种。补铝的分子筛表面酸性质发生了变化 ,改善了某些催化反应性能