高度有序多孔阳极氧化铝膜形成机理的探讨

使用高纯铝片,利用电化学阳极氧化制备了多孔阳极氧化铝(AAO)膜,用原子力显微镜(AFM)对其形貌进行了表征,提出铝阳极氧化过程中纳米孔从无序到有序的自组织模型,探讨了高度有序六角形纳米孔阵列的形成过程,并分析了影响纳米孔有序度的因素及提高有序度的途径.根据自组织模型探讨了长时间阳极氧化和二次氧化条件下形成高度有序六角形纳米孔阵列的机理.     

外表面不同孔结构的阳极氧化铝模板的自组织制备

经二次阳极氧化制备了外表面不同孔结构的阳极氧化铝模板.用场发射扫描电镜(FE-SEM)对其形貌进行表征,发现在直接阳极氧化的铝箔的外表面自组装形成了规则的六方形的纳米孔,而在去除铝基、扩孔的另一外表面则形成了规则的圆形的纳米孔,外表面纳米孔的平均直径大约为80nm,孔间距大约为110nm,孔密度约为2.5×10n cm-2.在模板的内部形成相互平行且垂直于AAO模板外表面的纳米管的阵列结构,纳米管的平均直径大约为80nm;AAO模板的厚度大约为10/zm.粉末X射线衍射(XRD)表明模板具有非晶态的结构.记录了阳极氧化过程中的电流一时间曲线,探讨了自组织孔洞的形成机理,提出了新型阳极氧化铝模板制备纳/微米结构材料模拟应用.     

阳极氧化法制备TiO_2和Al_2O_3有序多孔阵列

采用阳极氧化法制备了TiO2和Al2O3有序多孔阵列,并通过X射线衍射(XRD)、场发射扫描电子显微镜(FESEM)、莱茨光学显微镜对制备的TiO2和Al2O3有序多孔阵列进行表征。结果表明,随着氧化电压的增大,TiO2和Al2O3纳米孔的直径增加,孔密度减小。随着氧化时间的延长,TiO2和Al2O3多孔膜厚度增加,到一定时间后膜厚不变。同时讨论了阳极氧化机理,无论是制备TiO2还是Al2O3有序多孔阵列,阳极氧化过程主要由3个阶段组成:阻挡层的形成、阻挡层的溶解、多孔层的稳定生长。     

单通氧化铝模板的制备及工艺优化

利用高纯铝片采用两步阳极氧化法制得排列高度有序、尺寸可控的单通氧化铝(anodic aluminum oxide templates,AAO)模板,且纳米孔呈六方形结构。分别探究了预处理条件、氧化次数、扩孔时间等对AAO模板尺寸及有序性的影响。结果表明,预处理利于纳米管形成高度有序结构,并发现二次阳极氧化法比一次阳极氧化法制备的纳米管排列更有序且孔径均匀;在0~75 min内,管孔径与扩孔时间呈线性关系,酸溶液对孔的腐蚀速率为0.601nm/min,在0~120min内,管长度与二次氧化时间呈线性关系,生长速率为0.28μm/min;最佳电解液浓度确定为0.3mol/L。为后续制备非对称丝岛状骨组织再生高分子薄膜奠定了良好基础。     

铝箔多孔阳极氧化铝膜的低温制备及其电化学性能

以多孔阳极氧化铝(AAO)膜制备纳米材料时降低AAO膜孔径至关重要,降低电压无法达到要求,而降低氧化温度可实现这一目标。在0.4 mol/L H3PO4溶液中加入70%～80%(体积分数)1,3-丙三醇(PDO),于-10～10℃下恒压110 V阳极氧化1 h制备了多孔阳极氧化铝(AAO)膜,并在0.50 mol/L H3BO3和0.05mol/L Na2B4O7溶液中于20℃下以0.5 mA/cm2进行填孔后处理。利用SEM,EDS,XRD分析了AAO膜的表面形貌与组成,并对AAO膜填孔前后的极化曲线和交流阻抗谱进行了测试。结果表明,膜孔径随氧化温度降低而降低,80%PDO,10℃所得AAO膜的成分包括65.94%(质量分数,下同)Al,12.79%C,20.29%O和0.98%P;随氧化温度升高和PDO含量下降,AAO膜的稳定电流密度增大;随氧化温度升高,膜阻挡层厚度增大;填孔试验前AAO膜只存在一个阻挡层的相位角峰,填孔后出现两个峰,中高频段体现封闭的阻挡层特性,低频段体现的是多孔层封闭部分的特性。     

阳极TiO_2薄膜两步施加电压法制备参数对其形貌的影响

Ti的硫酸阳极氧化中硫酸的腐蚀性不足以溶解TiO2阻挡层,采用高温、高电压又会使膜纳米孔的孔径大于200 nm,使其应用范围受到限制.采用两步施加电压的方法,对钛阳极进行阳极氧化处理,以期在不同的工艺条件下制备具有不同孔径和孔密度的氧化钛薄膜.使用扫描电子显微镜考察了初始电压、终态电压、电解液温度、氧化时间等工艺参数对阳极氧化钛薄膜形貌的影响.结果表明,初始电压对氧化钛薄膜形貌的影响是通过改变电解液/阻挡层之间的界面条件来实现的;随着阳极氧化时间的延长纳米孔的孔径减小,孔密度增大;提高电解液的温度不影响纳米孔的形成过程,但对氧化钛薄膜的生长过程产生了比较大的影响.     

阳极氧化法制备纳米级多孔氧化铝膜的研究

比较了电化学抛光前后铝片表面的微观结构,用阳极氧化法制备了纳米级多孔氧化铝膜,用扫描电镜研究分析了氧化铝膜孔的排列规律.结果表明其排列高度有序,呈理想的六方柱形结构.     

阳极氧化铝膜的制备和磁性纳米阵列

目的 为了获得一定的纳米孔排列结构。方法 采用了电化学阳极氧化法制备氧化铝纳米结构。可以得到具有不同参数的密集排列的六角形结构膜,其中的纳米孔具有高绘横比。结果 我们制备了阳极氧化铝膜,而后得到了Ｆｅ纳米阵列,从磁滞回线讨论了它的垂直磁化特性。结论 以阳极氧化铝膜为模板,在其中沉积磁性纳米颗粒,可以得到了磁性纳米阵列,它具备高的垂直磁化特性。     

纳米氧化铝有序多孔膜制备工艺研究

为了获得大面积有序孔排列以及不同孔径的氧化铝膜,采用二次阳极氧化法可制备大面积有序铝阳极氧化多孔(AAO)膜,着重研究氧化电压、氧化时间、电解液浓度以及扩孔时间对AAO膜孔径大小、膜层厚度和形貌结构的影响,用X射线粉末衍射(XRD)仪进行物相分析,利用扫描电子显微镜(SEM)表征多孔膜的形貌.结果表明,在700 ℃以下条件下AAO膜以无定形态存在,经800 ℃退火后无定形氧化铝转化为γ-Al2O3,多孔膜随电压和电解液浓度增加而增大,经H3PO4溶液扩孔后可获得较大孔径模板,扩孔时间与孔径变化呈近似线性关系.为满足应用需求的AAO膜的制备提供了依据.     

多孔阳极氧化铝微孔结构的调控

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。     

阳极氧化铝底层对SmTbCo薄膜磁性能与结构影响的研究

采用两次阳极氧化法制备了孔洞排列有序的多孔氧化铝基底,并在其上用磁控溅射法制备了SmTbCo垂直磁化膜. 振动样品磁强计（VSM）测试结果显示,加入阳极氧化铝底层后可以将SmTbCo薄膜的矫顽力从370kA/m提高到530kA/m,并且随着氧化铝底层孔洞直径的减小,上层SmTbCo磁性薄膜的矫顽力与剩磁矩形比随之增大. 由薄膜断面的扫描电镜（SEM）照片可以看出,阳极氧化铝底层由于其自组织效应所形成规则密集的六角边形多孔结构能够明显促使上层的SmTbCo磁性薄膜生成柱状结构. 这一柱状结构提高了薄膜的矫顽力,从而拓宽了SmTbCo薄膜材料在超高密度垂直磁记录中的应用.     

One-step anodization fabrication and morphology characterization of porous AAO with ideal nanopore arrays

A fabrication method for one-step anodization of an anodic aluminum oxide (AAO) template with nanopore arrays using pretreated high purity aluminum foil is reported in this article. Morphology of the AAO was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Results showed that porous AAO with ideal nanopore arrays can be fabricated by one-step anodization fabrication technology on high purity aluminum foil which had been anodized at 45?V direct current (DC), in 0°C, 0.5?M H₂C₂O₄ solution for 48 hours. The average pore diameter and the interpore distance were 80?nm and 120?nm, respectively. Nanopores in porous AAO had very narrow size distribution and were arranged into hexagonal array. The formation mechanism of nanopore arrays in porous AAO is discussed. Porous AAO with ideal nanopore arrays provide an ideal template for preparation of many one-dimensional nanomaterials. One-step anodization of AAO is a simpler procedure and more applicable in industrial application than the previous two-step anodization technology.     

Structure-dependent adhesion and friction on highly ordered metallic nanopore membranes

Highly ordered metallic nanopore membranes are fabricated by direct deposition of nickel on typical porous anodic alumina (PAA) templates. The large-area uniform nanopore arrays of the PAA templates are accurately transferred to the metallic nanopore replicas, depending on the thickness of the deposited metal and the pore size of the base template. We demonstrate the ready tunability of the pore size and reproducibility of the metallic nanopore structure in a wide range of pore sizes. The adhesion and friction characteristics of the metallic replicas are studied according to the pore size using atomic force microscopy (AFM). As the pore diameter increases, the friction coefficients increase nonlinearly, and the adhesive forces scarcely change. These characteristics are understood in terms of the structural properties of the replicas, specifically the surface morphology and the real contact area. Initial pore formation from a flat thin film reduces the adhesive force by up to four times.     

Voltage-dependent fabrication of nanoporous alumina and the applications to nanocapacitors

We investigated the fabrication of anodized aluminum oxide by anodization processes under DC and AC voltage biases. A two-step anodization process was used to fabricate the anodized aluminum oxide dielectrics in order to regulate the ordered nanopore array at the surface. AC samples showed the distorted nanoporous structure instead of a straight nanopore array in DC samples. As increasing the frequency of AC bias the nanovoid or nanocavity structure was formulated with the increased density of nanovoids. Nanoporous alumina was used for the fabrication of Ni-insulator-Al capacitors. The DC sample shows the tunneling process of an increase in leakage current and breakdown. When a negative voltage is applied to the capacitor device, the small current of 2 nA flows at a voltage of 0 V, indicating the existance of residual leakage current. The AC sample had very low leakage currents of the AAO dielectrics and the AAO hexagonal unit cell formed the nanocapacitor with a capacitance of 1-2 aF.     

用低纯度铝制备AAO模板及其结构研究

在0.3mol/dm3草酸溶液中,通过不同纯度铝的恒电位二次阳极氧化制备了纳米孔氧化铝模板,并用场发射扫描电子显微镜(FE-SEM)和原子力显微镜(AFM)观察模板结构.实验结果表明,一次氧化除膜后低纯度铝基体表面呈现较为规则的六边形结构,这种蜂巢结构有利于二次氧化过程中获得有序度更高的纳米孔模板.低纯度铝制备的模板表面被晶界分隔为微小的区域,只是在较窄区域内才出现六边形规则排列的纳米孔.恒电位40V时所得模板经扩孔处理后,孔径由35nm增大到100nm左右,且孔径大小几乎一致.从纳米孔的有序度来看,由低纯度铝制备模板还需要进一步优化阳极氧化参数.     

阳极氧化铝模板上扩散聚合法制备聚苯胺纳米管(线)阵列

以多孔阳极氧化铝（AAO）为模板，利用扩散聚合法让苯胺单体溶液和氧化剂溶液在一维纳米孔道中相互扩散，在孔内形成聚苯胺（PANI）纳米管和纳米线阵列。利用SEM、TEM、IR和XRD等检测技术对阵列进行表征。结果表明，聚合反应优先发生在孔壁上，并沿孔壁逐层生长，直至形成实心的纳米线阵列。在孔径为60nm的AAO模板内，扩散聚合40min可形成聚苯胺纳米管阵列，2h后形成聚苯胺纳米线阵列；聚苯胺纳米管（线）中同时包含结晶相和无定型相结构。用二探针法测量PANI／AAO复合阵列电阻，计算出单根聚苯胺纳米线的电导率为21．4S／cm。此外，对扩散聚合过程中聚苯胺纳米管（线）阵列的形成原因进行了初步分析和探讨。     

Preparation of polyaniline nanotubes array based on anodic aluminum oxide template

In this article, the highly ordered polyaniline (PANI) nanotubes array was prepared by in situ polymerization using anodic aluminum oxide (AAO) as template. Polymerization of aniline was confined in the one-dimensional nanochannel of AAO template. The aniline was adsorbed and polymerized preferentially on the pore walls of template. The structure of PANI nanotubes array was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), selected area electron diffraction (SAED) and dynamic force microscope (DFM). The results show that PANI nanotubes are synthesized successfully in the nanopores of template, the diameter and length of PANI nanotubes are closed to the pore diameter and thickness of AAO template, respectively, the arrangement of PANI nanotubes is very regular and uniform, the crystal form of PANI nanotubes is hexagonal, different from pseudo-orthorhombic crystal form of PANI bulk sample, and cell parameters a and b are 0.5008 nm. The change of crystal form is due to the confinement of AAO template, which makes the molecular chain of PANI arrange more ordered.     

六角晶格多孔Si纳米阵列的制备研究

采用AAO模板7LAr＋磨技术在Si基片上合成了大面积规则的六角纳米孔阵列,阵列六角晶格尺寸及纳米孔深度可由H3PO4扩孔时间、氧化电压、离子磨时间等工艺参数精确控制。孔间距、孔直径与工艺参数的关系为ID=15．8＋2．17V和蹄0．905V＋0．452TH-20,其中V为氧化电压,TH为H3PO4扩孔时间;孔深度则可被控制为：Y=27．59T-5．44X＋21．76,X为AAO模板长径比,T为离子磨时间。该制备方法将可广泛应用于高效荧光发光器件、太阳能光伏器件、气体传感器件和THz受激辐射等光电子器件。     

Electrical-bridge model on the self-organized growth of nanopores in anodized aluminum oxide

Anodic aluminum oxide (AAO) has attracted a lot of attention for its application on the template-synthesis of nanomaterials. Highly ordered AAO template is essential to its applications. Here, we propose an electrical-bridge model based on the analysis of carrier ion drifts in the oxide layer and the electrical-field distribution. This model can elucidate the AAO growth mechanism, and allow better understanding of the nature of the nanopore self-organization during the anodic formation of AAO. The electrical-field distribution was greatly affected by the thickness of the oxide layer that is determined by the radii of cell and nanopore. The variable bridge resistances are related to anodizing conditions, such as temperature, which influence the ordering. The nanopores acquire uniformity by self-adjustment via the electrical bridge. Based on this model, the formation of hexagonal morphology of AAO, which is more stable than other arrangements, becomes a natural result of self-organization and the effect of anodizing conditions on the ordering is elucidated.