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《功能材料与器件学报》2017,(1)
多孔阳极氧化铝(AAO)是一种在酸性电解液下,通过施加电压对金属铝阳极氧化获得的多孔膜材料。AAO在当今纳米材料领域有着非常多的应用,如制备纳米阵列、进行纳米复制、制备量子点等。本文采用二次氧化法制备了AAO模板,研究了硫酸、草酸两种电解液以及氧化电压对纳米孔的影响规律。采用扫描电子显微镜(SEM)对样品的表面形貌进行分析,研究了制备工艺对孔形态的影响。通过统计不同氧化电压下AAO孔的圆度和孔径的分布,发现圆度随着电压的升高而升高。孔径随电压的升高而增大,两者呈现成指数型关系。 相似文献
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电解电压、电解质种类以及添加剂等因素对氧化铝多孔膜的形成过程有显著影响.在电解液中加入甘油作为添加剂,不但可以增加阳极氧化形成的多孔膜的厚度,而且有利于增强氧化膜的韧性.采用高纯铝作阳极,铂网作为阴极,在草酸溶液中进行恒压阳极氧化.研究了在3%(质量分数)草酸溶液中,添加甘油对氧化铝多孔膜形成过程的影响.结果发现,添加甘油并不会改变氧化铝多孔膜的形成过程,也不会改变形成氧化铝多孔膜中Al2O3的非晶态结构,但甘油的加入将降低阳极氧化时多孔氧化铝膜的生长速度以及氧化铝阻挡层的形成速度,同时增加了纳米孔阻挡层的厚度,因此增加阻挡层的形成时间.在阳极氧化电解液中加入甘油还有利于减小氧化铝多孔膜的纳米孔孔径. 相似文献
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利用二次阳极氧化法在纯铝表面构建出具有纳-纳双重层级结构的阳极氧化膜.溶去一次阳极氧化膜所形成的纳米坑为一级结构,二次阳极氧化形成的纳米孔为二级结构.纳米坑和纳米孔的直径取决于阳极氧化电压、电解质种类、电解液温度等工艺条件,并在一定范围内独立可调.延长一次氧化时间可以提高纳米坑阵列的规整度;延长二次氧化时间将使一级结构即纳米坑的深度变浅. 相似文献
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高度有序多孔阳极氧化铝模板的制备 总被引:1,自引:0,他引:1
为了得到纳米孔排列高度有序的多孔阳极氧化铝模板,以0.3 mol·L-1的草酸为电解液研究了模板的制备工艺.采用场发射扫描电子显微镜(FE-SEM)对多孔氧化铝模板的表面形貌进行表征,X射线衍射分析高纯铝及氧化膜的结构.实验结果表明,铝基体不经过高温退火处理,同样能够得到高度有序的氧化铝膜,简化了多孔氧化铝膜的制备工艺.分别讨论了阳极氧化电压和电解液温度对多孔阳极氧化铝膜的形貌及孔径的影响,并对一步法和两步法制得的多孔氧化铝膜进行比较,结果表明,两步阳极氧化法制备的多孔氧化铝模板的有序性优于一步氧化法.XRD分析证实,多孔氧化铝膜由非晶态的Al2O3组成. 相似文献
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Transparent thin films comprised of highly ordered titania nanotube-arrays were grown from titanium thin films using an anodization technique, from which highly sensitive and selective hydrogen sensors that can operate at room temperature were fabricated. Titanium films sputter deposited on glass at 500 °C were anodized in a fluorine-containing electrolyte to obtain nanotube-array films. Precise monitoring of current during the anodization enabled removal of the samples from the anodization bath at a point where the remaining metal layer became discontinuous, without destroying the nanotube architecture. The samples were then annealed in oxygen at 420 °C to crystallize the nanotube-arrays as well as oxidize any un-anodized metallic regions, yielding transparent films comprised of titanium oxide nanotube-arrays. Herein, we discuss the morphology, structure and optical characterization of these films. When coated with a 10-nm discontinuous palladium layer, the optically transparent nanotube-array films serve as excellent hydrogen sensors, exhibiting a four-order magnitude drop in resistance with exposure to 1000 ppm hydrogen at room temperature. 相似文献
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Highly oriented titania nanosheet thin films on Pt substrate were fabricated by electrophoretic deposition. The structure and morphology of thin films formed under a variety of conditions are characterized by X-ray diffraction and field-emission scanning electron microscopy. It was found that the quality of titania nanosheet precursor suspension and electrode potential play crucial roles in the film morphology. After the colloidal suspension is optimized by settling for 2 months, the surface of the deposited film is smooth, and the layered structure is dense and well-organized. Film thickness increases with increasing electrode potential, deposition temperature and deposition time. The delicate balance among the above factors that govern the film quality and thickness should be discerned. The films can exhibit a smooth surface and well-organized layered structure under the optimal deposition conditions. 相似文献
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Sachiko Hiromoto Akiko Yamamoto 《Materials science & engineering. C, Materials for biological applications》2010,30(8):1085-1093
The control of degradation rate of bioabsorbable magnesium devices is crucial for their biomedical applications. In this study, the influence of anodizing voltages and autoclaving on the degradation behavior of anodized pure magnesium was examined by immersion tests in a culture medium for 14 d. The anodization and autoclaving varied the morphology of surface film. Porous films were formed at 7 V and 100 V, and non-porous films were formed at 2 V and 20 V. The microscopic appearance of the anodized films did not change by autoclaving. The degradation rate on Day 1 was the highest and subsequently decreased to a quasi-steady state within the initial 3–5 d. The 7 V- and 100 V-anodized specimens showed the highest and the lowest quasi-steady degradation rate, respectively. The autoclaving significantly retarded the degradation of the anodized specimens. These facts revealed that anodization and autoclaving are useful for the control of the degradation rate of magnesium and its alloys. The porous anodized films showed local corrosion, whereas the non-porous anodized film formed at 20 V did not show apparent local corrosion. The local corrosion was prevented by autoclaving. These results suggest that the occurrence of local corrosion depends on the porous morphology of surface film. 相似文献
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铝箔阳极氧化后2种铈转化膜的沉积机理 总被引:1,自引:0,他引:1
为探讨铝阳极氧化沉积铈转化膜形成机理,分别用化学沉积和电沉积法在铝阳极氧化膜上制备了铈转化膜._用SEM和EDS表征了阳极氧化膜、化学沉积铈转化膜和阴极电沉积铈转化膜的形貌和组分,测试了膜层厚度和膜的耐腐蚀性.结果表明:平均孔径89 nm的铝阳极氧化膜经阴极电沉积、化学沉积铈后平均孔径分别减小为38 nm和32nm,2种沉积分别可得到含铈52.10%和20.39%的铈转化膜.2种铈转化膜的平均膜厚分别比铝阳极氧化膜的大1.96 μm和1.23 μm,极化电阻均是铝阳极氧化膜的近3倍.2种铈转化膜形成机理不同是造成它们性质不同的原因. 相似文献
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Polymeric films containing titania nanoparticles have potential as dielectric films for flexible electronic applications. For this purpose, the nanoparticles must be homogeneously distributed. Self-assembly is emerging as a neat, elegant method for fabricating such nanostructured hybrid materials with well-distributed nanoparticles. In this work, we report a micellar solution approach for the assembly of copolymer-titanium precursor nanostructures in which titania nanoparticles were synthesized. The ratio of the amount of titanium precursor, titanium isopropoxide, to the blocks forming the micellar core, poly(4-vinylpyridine), was found to play a key role in controlling film morphology. A sphere-to-ribbon transition was observed when the amount of titanium isopropoxide was increased. The thin film morphology can be tuned using the precursor-copolymer interaction rather than just the polymer-polymer interaction or the polymer-solution interaction. This method provides yet another way to control the morphology of nanostructures. 相似文献
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Mesoporous titania films of low refractive index ∼1.72 and thickness within the range of 57–96 nm were fabricated via sol–gel rout and dip-coating technique on a soda–lime glass substrate. Tetrabutylorthotitanate Ti(OBu)4 was used as a titania precursor. High porosity and consequently low refractive index were achieved using the polyethylene glycol (PEG 1100) as a template. Based on transmittance, using Tauc’s relations, the optical energy band gaps and the Urbach energy were determined. The research shows that in the fabricated titania films there are two types of optical energy band gaps, connected with direct and indirect electron transitions and brought about by the presence of amorphous and crystalline phase respectively. Based on the quantum size effect, the diameters of nanocrystals versus film thickness were determined. AFM studies of the titania films have demonstrated that there are changes of surface morphology taking place with the change of thickness. We have demonstrated that the surface morphology of titania films has influence on wettability. 相似文献
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Ji Y Lin KC Zheng H Liu CC Dudik L Zhu J Burda C 《ACS applied materials & interfaces》2010,2(11):3075-3082
Transparent photocatalytic surfaces are of ever increasing importance for many applications on self-cleaning windows and tiles in everyday applications. Here, we report the formation and photocatalytic testing of a quasi-transparent thin and nanoporous titania films deposited on glass plates. Sputtered Ti thin films were anodized in fluoride-ion-containing neutral electrolytes to form optically semitransparent nanoporous films, which transformed to be completely transparent after thermal annealing. The nanoporous films were studied at different stages, such as before and after anodization, as well as after thermal annealing using scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-vis and Raman spectroscopy. It was observed that anodization at 20 V of high-temperature deposited titanium films resulted in regular nanopore films with pore diameters of 30 nm. Structural investigations on the transparent nanopore arrays reveal the presence of anatase phase TiO(2) even after annealing at 500 °C, which was confirmed by XRD and Raman spectroscopy measurements. The solar-light induced photocatalytic decomposition of stearic acid and photoconductivity characteristics of these nanoporous thin films are also presented. 相似文献
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The effects of anodization parameters on titania nanotube arrays and dye sensitized solar cells 总被引:1,自引:0,他引:1
Ordered, closely packed, and vertically oriented titania nanotube arrays with lengths exceeding 10?μm were fabricated by anodization of titanium foils. The effects of anodization voltage and time on the microstructural morphology and the photovoltaic performance of dye sensitized solar cells based on the titania nanotube arrays were investigated. On increasing the anodization voltage or time, the increase in active surface area leads to enhanced photovoltaic currents and thereby an overall higher performance of the dye sensitized solar cells. The efficiency enhancement with rising anodization voltage exceeds the increase in the outer surface area of the nanotubes, indicating that the active surface area is further enlarged by a more accessible inner surface of the nanotube arrays grown with a higher anodization voltage. A promising efficiency of 3.67% for dye sensitized solar cells based on anodized titania nanotube arrays was achieved under AM1.5, 100?mW?cm(-2) illumination. 相似文献
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M. Koopman K. K. Chawla W. Ricci K. Carlisle G. M. Gladsyz M. Lalor M. L. Jones K. Kerr M. P. George G. Gouadec Aurélie Tournié 《Journal of Materials Science》2009,44(6):1435-1441
Functional titania coatings on glass microballoons (GMBs) and cenospheres have a broad range of potential environmental applications,
primarily in purification of drinking water and treatment of industrial wastewater. The heterogeneous photocatalytic capabilities
of titania films and particles have been extensively examined in the literature as effective alternatives to current technologies.
Although the chemistry of titania films for photocatalysis has been studied, titania-coated GMBs have not yet been extensively
considered and the materials science aspects of the titania-GMB and titania-cenosphere systems have not been addressed. We
have examined the microstructure, morphology, and mechanical properties of titania coatings on both cenospheres and commercially
produced GMBs. Scanning electron microscopy was used to examine coating coverage and defects. Energy dispersive X-ray spectroscopy
and Raman spectroscopy were used for element and phase identification, respectively. Hardness and modulus measurements of
the titania coatings and the GMB and cenosphere materials were done by nanoindentation. Additionally, the photocatalytic activity
of the titania-coated GMB system was tested on Procion Red dye using two different types of mixing, a magnetic stirrer and
an aeration bubbler apparatus. The titania coatings showed good coverage and retention except in the case of magnetic stirring,
where significant coating loss was observed. 相似文献
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《Materials Letters》2005,59(24-25):3138-3143
Gel titania is the titania which was prepared by hydrolysis of a titanium isopropoxide through a sol–gel process. A film of this titania was coated on surgical grade 316L stainless steel using a sol–gel dipping technique. The densified films at 700 °C in vacuum were characterized by X-ray diffraction and EDXA analysis for its crystallinity and purity. The content of the films were determined by FT–IR spectroscopy. The morphology of the coating was analyzed by SEM. The corrosion behavior of 316L SS samples coated with densified titania films were studied in simulated body fluid Ringer's solution by DC potentiodynamic polarization and AC impedance spectroscopic methods. The corrosion kinetic parameters show a considerable increase in the corrosion resistance for the coated steel samples in comparison to the pristine steel substrates. 相似文献