钛合金阳极氧化着色技术的研究进展

阳极氧化着色技术是一种在Al、Mg、Ti等有色金属及其合金表面原位生长氧化膜的传统技术.用该技术制成的氧化膜色彩均匀鲜艳,结合力高,具有优良的耐腐蚀性和生物相容性,已广泛应用于生物医学和航空航天领域.介绍了氧化钛膜的发色原理,综述了阳极氧化着色技术在国内外的研究现状,概括了阳极氧化着色的工艺方法、氧化钛膜制备过程的影响因素和钛合金阳极氧化的应用领域,并展望了该技术的应用前景.     

Al-Li合金阳极氧化膜的制备与性能

Al-Li合金在潮湿和盐雾环境中易发生晶间腐蚀、剥落腐蚀和应力腐蚀等形式的破坏。为了提高Al-Li合金的耐蚀性,采用阳极氧化的方法,在15%硫酸溶液中在Al-Li合金表面制备了一层Al_2O_3阳极氧化膜,通过测厚仪及显微硬度计测试了膜层厚度及硬度,通过扫描电镜、电化学测试和腐蚀试验等方法,研究了电流密度、氧化时间等对阳极氧化膜耐蚀性的影响。结果显示:所得氧化膜表面呈多孔状结构,厚度在3~13μm之间,硬度在80~200 HV之间;当电流密度为2.0 A/dm~2、氧化时间为60 min、沸水封孔处理20 min时制备的阳极氧化膜耐蚀性最优。     

医用NiTi形状记忆合金表面氧化改性研究进展

氧化是NiTi形状记忆合金表面改性的重要手段,常用的氧化工艺包括热氧化、微弧氧化、阳极氧化和化学氧化。虽然四种工艺都依靠合金自身的Ti元素在合金表面原位生成以晶态或非晶态TiO2为主的氧化膜,但四种氧化工艺的原理及所制备的膜层形貌、结构等均不相同。本文评述了四种表面改性工艺的优势和缺陷,并对NiTi合金表面改性的发展方向进行了展望。     

铝箔表面复合阳极氧化膜研究

采用溶液浸渍法在低压腐蚀铝箔表面沉积一层Ti氧化物．然后将试样在有机盐水溶液中阳极氧化至20．0V。在恒流升压过程中,记录电压-时间曲线。借助XPS和XRD等分析手段分析阳极氧化膜结构,并对复合阳极氧化膜的生长机理进行了探讨。结果表明：含Ti处理液浸渍处理后,试样阳极氧化的电压-时间曲线斜率显著增大,阳极氧化膜是由Al2O3和TiO2构成的复合阳极氧化膜,其介电常数高于Al2O3阳极氧化膜,使阳极箔比容提高24．8％。     

Al和Nb元素对高Nb-TiAl合金高温氧化行为的影响EI北大核心

利用SEM,XRD和EPMA研究了Ti45Al8Nb,Ti45Al12Nb,Ti52Al8Nb和Ti52Al12Nb四种合金在900℃空气中100 h的氧化行为。结果表明:四种含铌合金的抗氧化性均大幅度优于无铌合金。高的Al含量可提高合金抗氧化性,52Al合金氧化膜内均有更稳定的Al2O3出现,氧化膜下出现贫铝区。Ti52Al8Nb合金氧化膜除外层生成Al2O3保护层外,内层还分布着岛状Al2O3。12Nb合金氧化膜内出现更多的Nb2Al相,其对于合金抗氧化性并不总是有利的。更高的Al和Nb含量均改变氧化膜的生长机制。合金具有最优的抗氧化性需要Al和Nb元素协同作用。     

铝合金Ti(C,N)/TiN多元多层膜与阳极氧化膜性能比较

分别采用多弧离子镀技术及阳极氧化技术在LF6防锈铝基体表面制备了Ti(C,N)/TiN/Ti(C,N)/TiN/ Ti(C,N)/TiN六层多元多层膜及阳极氧化膜,并对比考察研究了该两种膜的力学性能和摩擦学性能,结果表明:多元多层膜与阳极氧化膜划痕临界荷载分别为76N,60N;显微硬度分别为HV0.251404,HV0.25520;二者摩擦系数都较高,分别为0.66,0.76;都使对偶件磨损;但与传统的阳极氧化膜相比,多元多层膜硬度与耐磨性都提高了近2倍,且其摩擦曲线平滑,呈稳定磨损状态,而阳极氧化膜摩擦曲线呈跳跃状,呈非稳定磨损状态.     

铝合金中的硅对阳极氧化的影响

本文叙述了在硫酸添加草酸的氧化溶液中,以同样的工艺对含硅的铸铝合金和轧制铝合金进行硬质阳极氧化处理所得到的氧化膜垂直横截面的金相形貌却不同。通过电子探针分析,在氧化膜不均匀和不完整的部位夹杂有硅,因为硅在氧化过程中不溶解,而其他的合金元素溶解于溶液中,硅在合金中阻止了铝的氧化,结果,使含硅铸铝合金阳极氧化膜不均匀、不完整。本文初步阐述了含硅铸铝合金难于阳极氧化的机理     

工艺参数对2195铝锂合金阳极氧化膜层腐蚀行为的影响

现有的成熟传统铝合金阳极氧化工艺参数对铝锂合金不完全适用。为此,采用硫酸直流阳极氧化法在2195铝锂合金表面形成阳极氧化膜,研究了氧化时间、电流密度以及封闭处理对膜层耐腐蚀性能的影响。结果表明:膜层厚度随氧化时间和电流密度的增加而增加,随着氧化时间的延长,膜层厚度增长速度加快。阳极氧化时间为60 min且电流密度为2.5～3.0 A/dm2时,2195铝锂合金具有较低的腐蚀电流和较高的阻抗,表明膜层具有较好的耐腐蚀性。经重铬酸钾封闭处理后,2195铝锂合金的耐腐蚀性能明显提高。     

水解沉积--阳极氧化法形成Al-Ti复合氧化膜

通过含钛无机盐的水解沉积及高温热处理,铝电极箔表面形成高介电常数氧化物———TiO2 膜层,然后在己二酸铵溶液中恒电流阳极氧化,形成 Al Ti复合氧化膜。AFM观测了含钛无机盐水解沉积过程中,铝电极箔表面形貌的变化。在铬酸和磷酸的混合溶液中测试了氧化膜的耐电压随溶解时间的变化。通过SIMS检测了复合氧化膜中 Al3 、Ti4 的强度随溅射时间的变化。膜溶解试验及 SIMS 检测结果表明Al Ti复合氧化膜由 3 层组成,外层和中间层为 Al、Ti、O不同配比的混合物,内层则为纯的 Al2O3。铝电极箔比容随氧化膜耐电压的变化关系曲线表明,60V耐电压下,Al Ti复合氧化膜的比容提高率为51%。     

紫铜及铝青铜合金高耐蚀性阳极氧化工艺研究与生产应用

为改良T1紫铜、QAl9-4铝青铜合金的外观并提高耐腐蚀性能,使用氢氧化钠、钼酸铵的水溶液作为工作溶液,对T1紫铜、QAl9-4铝青铜合金进行阳极氧化处理。采用扫描电子显微镜、能谱和金相显微镜测试2种材料表面的阳极氧化膜层的显微形貌、主要成分和金相组织,从而优化阳极氧化工艺参数。通过外观检测、附着强度测试、耐高温、中性盐雾试验等检测方法考核了阳极氧化膜层的综合性能。结果表明：阳极氧化电流密度为1.0 A/dm²,时间为25～30 min,温度为80～90℃时,可以获得厚度为1～3μm、可耐温400℃的黑色氧化膜。经适当封闭处理的2种材料表面的阳极氧化膜层阻碍了腐蚀介质的扩散,T1紫铜耐腐蚀性提高6.0倍,QAl9-4铝青铜合金耐腐蚀性提高2.5倍。生产应用表明该工艺稳定、操作简便,适用于T1紫铜、QAl9-4铝青铜合金材料产品大批量生产,能够满足产品装饰性、消光性、耐高温性和耐腐蚀性要求。     

Corrosion protection of biodegradable magnesium implants using anodization

Magnesium (Mg) and its alloys are emerging as a possible biodegradable implant material. However, Mg implants may degrade too quickly in the body, before the natural healing process is complete. In this work, anodization was investigated to slow down the initial corrosion of Mg in a simulated body corrosive environment. Pure Mg and AZ91D alloy were anodized and their corrosion resistance was compared in terms of anodization behavior and parameters such as applied voltage and current with different anodization time. Electrochemical impedance spectroscopy, DC polarization, and immersion testing were used to evaluate the corrosion resistance of Mg samples and further optimize anodization parameters. The results showed that anodization increased the corrosion resistance of both pure Mg and AZ91D samples. Further characterization showed the anodized layers on both pure Mg and AZ91D consisted of Mg, O and Si, in the mixture of MgO and Mg₂SiO₄.     

包铝层和氧化时间对2E12铝合金硫酸阳极氧化及膜层性能的影响

对保留表面包铝和去除包铝的2E12-T3铝合金采用硫酸阳极氧化处理工艺,研究了包铝层和氧化时间对铝合金阳极氧化行为及膜层耐蚀性的影响。采用扫描电子显微镜观察氧化膜的表面以及截面形貌,应用动电位扫描极化曲线和电化学阻抗谱对膜层的电化学性能进行分析。结果表明:两种铝合金表面均能形成具有防护性能的阳极氧化膜,膜层随氧化时间延长而增厚。富铜的第二相颗粒会使得不带包铝的2E12铝合金氧化膜具有更多孔洞缺陷,甚至出现微裂纹。保留包铝的2E12铝合金表面氧化膜更厚,孔洞缺陷少,耐蚀性更好。阳极氧化30min和45min的2E12铝合金阳极氧化膜具有较低的腐蚀电流和较高的多孔层阻抗,耐蚀性好。     

KH-560改性SiO2绝缘薄膜的制备及性能研究

软磁合金是新一代质子/重离子同步加速器加速器的核心材料,在其表面涂覆绝缘涂层可有效降低高频涡流损耗。同时,高温热处理(~600 ℃)可有效减少软磁合金冷压成形产生的缺陷和位错而引起的内部残余应力。因此,软磁合金用绝缘涂层还需满足耐高温要求。SiO₂涂层是最常见的无机涂层材料,具有良好的绝缘性能和耐高温性能。本工作在植酸催化TEOS+MTES制备硅溶胶的基础上,加入硅烷偶联剂KH-560进一步提高硅溶胶的成膜性能,系统研究了KH-560对SiO₂涂层结构与性能的影响,并系统分析了KH-560提高SiO₂涂层性能的机理。研究表明,添加适量的KH-560可有效提高薄膜的稳定性和成膜性。特别是当KH-560添加量为0.04 mol时,SiO₂涂层质量最好,SiO₂-0.04 KH涂层表现出最佳的耐腐蚀性和电绝缘性。在100 V时,SiO₂-0.04 KH涂层的方块电阻仍保持2.95×10¹¹Ω/□。综上,本研究利用植酸催化和KH-560改性协同作用制备出高质量的SiO₂涂层,涂层具有良好的耐高温和优异的绝缘性能。     

Fabrication and magnetic characteristics of vertical feco nanowire arrayed in Al2O3 insulator of honeycomb bulkhead structure

High-density and uniform-sized FeCo alloy nanowires were prepared by electro deposition of Fe2+ and Co2+ into Anodic aluminum oxide (AAO) templates with two different diameters. These templates were fabricated with three-step anodization method. The additional anodization after the 2nd anodization step resulted in the decrease of the thickness of bottom barrier layer. It found an optimum condition to obtain a successful electrodeposition of Fe2+ and Co2+ into AAO templates. The nanowires with the diameters of 25 nm and 80 nm were homogeneously embedded in the AAO templates and their magnetic properties were strongly affected by diameters of nanowire.     

激光熔覆CoCrFeMnNiMox高熵合金的组织和耐蚀性研究

目的 为了增强钢制结构表面的耐蚀性,研究Mo含量对CoCrFeMnNiMox高熵合金组织与耐蚀性的影响。方法 采用激光熔覆的方式在N80钢上制备CoCrFeMnNiMox（x=0.1、0.2、0.3、0.4、0.5）高熵合金熔覆层,研究Mo含量变化对高熵合金组织、物相与耐蚀性的影响。结果 CoCrFeMnNiMox熔覆试样均由单一的FCC固溶体相组成,随着Mo含量的增加,晶格畸变增大;当Mo的摩尔比超过0.3后,晶粒有长大倾向;Mo的摩尔比为0.5时,表面择优生长晶面由（111）密排晶面转变为（200）非密排晶面。熔覆试样在氯化钠溶液和稀硫酸溶液中的耐蚀性相较N80钢提升明显,其中,CoCrMnFeNiMo0.3的耐蚀性最好,在质量分数为3.5%的氯化钠溶液中其自腐蚀电流密度是N80钢的5%,自腐蚀电位比N80钢提高了1倍;在0.5 mol/L硫酸溶液中,其自腐蚀电流密度是N80钢的31%,钝化区电流密度比N80钢降低了1个数量级。结论 在该高熵合金体系中,随着Mo含量的增加,晶格畸变增大。CoCrMnFeNiMox高熵合金熔覆层可以有效地阻止基体腐蚀的发生。Mo元素在溶液中能够形成MoO3附着在金属表面,从而形成稳定致密的保护层,减少点蚀的发生。CoCrMnFeNiMo0.3熔覆层的耐蚀性最好。     

Effects of temperature and voltage mode on nanoporous anodic aluminum oxide films by one-step anodization

Many conventional anodic aluminum oxide (AAO) templates were performed using two-step direct current anodization (DCA) at low temperature (0–5 °C) to avoid dissolution effects. This process is relatively complex. Pulse anodization (PA) by switching between high and low voltages has been used to improve wear resistance and corrosion resistance in barrier type anodic oxidation of aluminum or hard anodization for current nanotechnology. However, there are only few investigations of AAO by hybrid pulse anodization (HPA) with normal-positive and small-negative voltages, especially for the one-step anodization, to shorten the running time. In this article, the effects of temperature and voltage modes (DCA vs. HPA) on one-step anodization have been investigated. The porous AAO films were fabricated using one-step anodization in 0.5 M oxalic acid in different voltage modes including the HPA and DCA and the environment temperature were varied at 5–15 °C. The morphology, pore size and oxide thickness of AAO films were characterized by high resolution field emission scanning electron microscope. The pore size distribution and circularity of AAO films can be quantitatively analyzed by image processing of SEM. The pore distribution uniformity and circularity of AAO by HPA is much better than DCA due to its effective cooling at relatively high temperatures. On the other hand, increasing environment temperature can increase the growth rate and enlarge the pore size of AAO films. The results of one-step anodization by hybrid pulse could promote the AAO quality and provide a simple and convenient fabrication compared to DCA.     

LC9铝合金常温硬质阳极氧化工艺和氧化膜显微组织的研究

对LC9铝合金使用硫酸为主、有机酸为添加剂的混合酸溶液进行了硬质阳极氧化的工艺研究。讨论了电流密度、温度和硫酸浓度等工艺参数对氧化膜的厚度和显微硬度的影响规律,确立了本试验的最佳工艺条件,并分析了工艺参数对氧化膜的厚度和显微硬度的影响机理。此外,利用金相显微镜和扫描电镜观察了氧化膜的组织结构,结果表明:氧化膜均匀、致密,界面较平直;氧化膜表面存在微裂纹和针孔,这是由膜层脆性较大、偏聚的合金相以及氧化膜缺陷和夹杂的溶解等因素造成的。     

Corrosion behavior of nanotubular oxide on the Ti-29Nb-xZr alloy

This work reports the corrosion behavior of nanotubular oxide layers on Ti-29Nb-xZr alloys with different compositions by anodization in 1 M H3PO4 + 0.8 wt% NaF. Depending on the alloy composition, nanoporous or highly ordered nanotube structures can be formed. The nanotube oxides on the Ti-29Nb-xZr alloy showed lower corrosion current density compared to non-treated sample.     

Fabrication of silicon-based template-assisted nanoelectrode arrays and ohmic contact properties investigation

A convenient fabrication technology for large-area, highly-ordered nanoelectrode arrays on silicon substrate has been described here, using porous anodic alumina (PAA) as a template. The ultrathin PAA membranes were anodic oxidized utilizing a two-step anodization method, from Al film evaporated on substrate. The purposes for the use of two-step anodization were, first, improving the regularity of the porous structures, and second reducing the thickness of the membranes to 100-200 nm we desired. Then the nanoelectrode arrays were obtained by electroless depositing Ni-W alloy into the through pores of PAA membranes, making the alloy isolated by the insulating pore walls and contacting with the silicon substrates at the bottoms of pores. The Ni-W alloy was also electroless deposited at the back surface of silicon to form back electrode. Then ohmic contact properties between silicon and Ni-W alloy were investigated after rapid thermal annealing. Scanning electron microscopy (SEM) observations showed the structure characteristics, and the influence factors of fabrication effect were discussed. The current-voltage (I-V) curves revealed the contact properties. After annealing in N2 at 700 degrees C, good linear property was shown with contact resistance of 33 omega, which confirmed ohmic contacts between silicon and electrodes. These results presented significant application potential of this technology in nanosize current-injection devices in optoelectronics, microelectronics and bio-medical fields.     

Dielectric properties of anodized Al-Ta alloy films with high Al content

At 1 mA cm^-2 the anodization voltage of sputtered Al-Ta alloy films with about 7 at.% Ta content rises linearly with time at a rate of 0.45 V s^-1. The Al-Ta thickness-anodization voltage ratio and the oxide growth constant have been determined, for 7–14 at.% Ta in the films with 1% citric acid electrolyte, to be 1.03-0.94 nm V^-1 and 1.42–1.5 nm V^-1, respectively. The permittivity was found to range from 10.0–11.4, corresponding to a capacitance density of about 330 pF mm^-2 for an anodization voltage of 200 V. The temperature coefficient of capacitance (t.c.c.) was 500 ppm K^-1. The capacitance between 400 Hz and 1 MHz remained constant within ±1%. At 1 kHz the disspation factor tan δ was 0.6%.Nearly all leakage currents were between 0.1 and 0.5 nA using 5.6 nF test capacitors and 50 V as the test voltage. This corresponds to an insulation resistance R of 10¹¹ Ω or more, or a time constant τ ( = RC) of approximately 1000 s. For the 50 V test the yield was about 90% and at least 80% of the capacitors had no short circuits after step stress tests up to 90 V.The current-voltage characteristics of capacitors made from Al-Ta (7 at.% Ta) films showed non-destructive breakdown voltages greater than 100 V. Only a slight deviation from symmetry was noticed whether the Al-Ta electrode was positive or negative, indicating that the capacitors were virtually non-polar. In some cases non-shorting breakdown was observed.