TEM characterization of super-hydrophilic Ni-Ti thin film

A super-hydrophilic Ni-Ti thin film is evaluated using cross-sectional transmission electron microscopy (TEM). Following sputter deposition and annealing, the Ni-Ti thin films are chemically treated with buffered oxide etchant, nitric acid and 30% hydrogen peroxide solution to produce a 100-nm-thick surface oxide layer. The fabricated Ni-Ti thin films show a 10- to 15-nm TiO₂ thick layer on its surface with a ~ 67° wetting angle. For the surface treated sample, a porous oxide 100 nm TiO layer is found with a < 5°. It is believed that TiOOH(H₂O)_n complex forms on the surface to produce the observed super-hydrophilic behavior.     

磁性纳米颗粒膜微波物性研究

采用磁控溅射工艺和复合靶技术制备FeCoB-SiO2磁性纳米颗粒膜;利用X射线衍射仪、扫描探针显微镜分析这类薄膜的微结构和形貌特征;采用振动样品磁强计、四探针法、微波矢量分析仪及谐振腔法测量薄膜试样的磁电性能和微波复磁导率;重点对SiO2介质相含量、薄膜微结构对电磁性能产生重要影响的机理做了分析和探讨.结果表明,这类FeCoB-SiO2磁性纳米颗粒膜具有良好的软磁性能和高频电磁性能,2GHz时,磁导率μ＞50,可以应用于高频微磁器件中.     

TEM characterization of iron-oxide-coated ceramic membranes

Commercially available porous alumina–zirconia–titania ceramic (AZTC) membranes having a titania surface coating were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), and the Brunauer–Emmett–Teller (BET) method. TEM photomicrographs showed the as-received AZTC membrane to be a multi-layered structure consisting of a porous alumina–zirconia–titania core having ultrafine pore sizes, coated by an additional layer of nanoporous titania. Electron diffraction studies revealed an amorphous surface titania layer while the underlying AZTC membrane was crystalline. The AZTC membranes were coated 20, 30, 40, 45, or 60 times with iron oxide (Fe₂O₃) nanoparticles, after which the membranes were sintered in air at 900 °C for 30 min. TEM revealed a relatively uniform nanoporous Fe₂O₃ coating on the sintered, coated membranes, where the Fe₂O₃ coating thickness increased with increasing number of layers. Electron diffraction patterns showed the Fe₂O₃ coating to be crystalline in nature. This was confirmed by the XRD results showing the structure to be α-Fe₂O₃, while the AZTC membrane was a mixture of the anatase and rutile phase of TiO₂ as well as ZrO₂ and corundum, Al₂O₃. The average pore size of the underlying AZTC membrane increased after the Fe₂O₃-coated membrane was sintered. The nanoporosity in the sintered Fe₂O₃ coating increased until 40 layers, beyond which no significant increases in the average pore size were observed. The iron-oxide-coated membrane improved catalytic properties when used in combination with ozone to treat water. The optimal benefit, in terms of water treatment efficacy, was found at 40 layers of Fe₂O₃.     

TEM characterization of indented polycrystalline Y-PSZ

The microstructural characterization of indented Y-PSZ polycrystals has been investigated by TEM. The observations show two different regions associated with the indent: a large core with a high density of monoclinic particles transformed from the initial tetragonal variant, and an inner core region with a high density of dislocations. The core region can be correlated with previous observations of a crack exclusion zone.     

XPS and TEM study of W-DLC/DLC double-layered film

A double-layered film of tungsten-containing diamond-like carbon (W-DLC) and DLC, (W-DLC)/DLC, was investigated. A film of 1.6 µm in thickness was deposited onto silicon substrate. The investigate double-layered coating was deposited by using the combination of PECVD and co-sputtering of tungsten metal target. Structure, interface and chemical bonding state of the investigated film were analyzed by Transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). From the results of the analyses, the structure of double-layered film is that amorphous phase of carbon is continued from DLC to W-DLC and tungsten metal clusters are dispersed in W-DLC layer.     

TEM study of the indentation behaviour of thin Au film on GaAs

Au films of 8.9 nm thickness have been sputter deposited onto a (001) GaAs substrate at room temperature. An average grain size of 10 nm and no texture were obtained. Subsequent, nanoindentation tests were performed on the coated specimens and the mechanical response was compared to that of a bulk GaAs sample with the same crystallographic orientation. Furthermore, the loading–unloading curves were analysed in view of transmission electron microscopy plan-view images obtained on the deformed substrate–film specimens and compared to results previously reported in the literature for bulk sample. Constrained plasticity of the films was observed to occur for residual depth to thickness ratio below 0.67. Further, plastic deformation of the substrate happened on coated specimens at loads less than those required to plastically deform bare substrate.     

On the use of TEM in the characterization of nanocomposites

Both an organically modified commercial clay of montmorillonite type (MMT) and its nanocomposites, based either on polyamide 6 (PA6) or an epoxy resin, as matrix polymer, have been characterized by transmission electron microscopy (TEM). Sample micrographs, taken at increasing exposure times (t_e), have shown the gradual disappearance of clay layers, because of an amorphisation of the MMT crystalline structures caused by prolonged sample exposure to electron beam. Indeed, the above phenomenon, which is mostly evident in the case of intercalated nanocomposites, makes the detection of the layered silicate dispersion in the polymer matrix rather difficult and compels to perform TEM measurements using very short exposure times. Moreover, the microscopy accelerating voltage has turned out to affect sample stability; namely, when decreasing the above parameter, the disappearance of clay structure occurs at lower exposure times.     

In situ TEM creation and electrical characterization of nanowire devices

We demonstrate the observation and measurement of simple nanoscale devices over their complete lifecycle from creation to failure within a transmission electron microscope. Devices were formed by growing Si nanowires, using the vapor-liquid-solid method, to form bridges between Si cantilevers. We characterize the formation of the contact between the nanowire and the cantilever, showing that the nature of the connection depends on the flow of heat and electrical current during and after the moment of contact. We measure the electrical properties and high current failure characteristics of the resulting bridge devices in situ and relate these to the structure. We also describe processes to modify the contact and the nanowire surface after device formation. The technique we describe allows the direct analysis of the processes taking place during device formation and use, correlating specific nanoscale structural and electrical parameters on an individual device basis.     

Mechanical characterization of free-standing polypyrrole film

Free-standing polypyrrole films, neutral or doped with ClO₄⁻, have been mechanically characterized. Their elasticity of both dry and wet states was characterized by mean of the Young's modulus. In addition, the Young's modulus was calculated as a function of the film oxidation deep by “in situ” polarization at different potentials ranging from − 0.6 up to 0.8 V. The samples also were characterized under oxidation and reduction by reverse constant currents. When the films were submitted to a constant stretching force the length variations were obtained. At a constant length of the sample the electro-chemo-mechanical force developed by the redox processes was obtained. As predicted by the ESCR model lineal variations of both, length and force, as a function of the consumed charge were obtained.     

聚氯代对二甲苯薄膜表面用紫外光固化漆的制备与表征

采用化学气相沉积聚合制备的聚氯代对二甲苯膜(简称PC膜)具有优异的阻隔性能,在多个行业得到广泛的应用。但其耐冲击性能较差,影响了其在某些领域的应用。通过在其表面涂覆柔韧性好的材料以提高其耐冲击性能是一种可选的改进方案。针对PC膜保护研制了一种紫外光固化漆并对其相关性能进行了表征。结果表明,研制的漆膜具有优异的附着力(0级)、柔韧性、耐酸碱性,漆膜对PC膜断裂伸长率和耐冲击强度都有显著提高;固化漆膜不降低PC膜对水蒸气的阻隔性能,而复合膜对空气和氢气阻隔性能有所增强。     

铝阳极氧化膜模板组装铜纳米线及其TEM表征

为了研究纳米线的微观结构，通过电化学交流电沉积的方法，以多孔阳极氧化铝膜（Al2O3/Al)为模板，制备了金属铜纳米线，利用透射电子显微及选区电子衍射技术对纳米线进行了表征，并从电化学角度探讨了铜纳米线凸凹相间条纹结构的形成机理，研究表明：铜纳米线具有凸凹的条纹结构，平均长度约为4μm，直径20nm；铜纳米线具有面心立方（FCC）的多晶结构，其凸、凹部位具有相同的物相组成。     

TiO2薄膜与玻璃基板横断截面的TEM及TEM—EDX分析

对玻璃基板上ＴｉＯ２薄膜与基板横断截面进行了ＴＥＭ形貌及ＴＥＭ－ＥＤＸ成分分析．结果表明,薄膜与基板结合致密,Ｎａ＋从基板向ＴｉＯ２薄膜的扩散为负扩散     

TEM characterization of some crude or air heat-treated SiC Nicalon fibres

Commercial Nicalon fibres were prepared by thin transverse sectioning and studied by transmission electron microscopy. A progressive tilting of the incident beam allows us to explore the selected-area diffraction (SAD) pattern along two orthogonal directions, increasing the tilting angle (dark-field (DF) imaging). The lattice fringes technique was also used. The samples were Nicalon 001, 101 and 201 fibres, the latter also being studied after heat treatment in air at 1300° C for 48 h. The SAD pattern of the 001 fibre only shows the SiC, 1 1 intense halo whereas the other samples show all the SiC (1 1 1, 2 2 0 and 31 1) strongly scattered beams, indicating a microcrystalline state. Correspondingly, DF imaging does not indicate any localized measurable scattering domain for 001. Only bright dots can be seen, less than 1 nm in size. The other fibres show SiC microcrystals respectively 2 nm (1 01 ), 3 nm (201 ) and up to 7 nm (heat-treated 201) in extent. Free aromatic carbon, shaped in small units less than 1 nm in size fills up the interstices between SiC. These units tend to lie flat on SiC. In heat-treated fibres, they form incomplete layers around the edges. In addition, the heat-treated 2 01 fibre show a 1m thick layer of cristobalite at the fibre surface. These crystals are polytypes.     

Aluminum alloy film deposition and characterization

A flash evaporation system which utilizes a mechanism for feeding alloy wire onto a heated bar was used for the deposition of aluminum-silicon, aluminum-copper and aluminum-copper-silicon. The effect of deposition conditions and processing procedure on film composition and microstructure was determined. Particular attention was given to the film surface topography and the possible influence of deposition conditions, alloy composition, substrate type, thickness, annealing time and temperature and addition of oxide overlayers. Resistivity, and possible shorting of junctions in silicon as a consequence of silicon dissolution in the metallization, were considered as a function of alloy composition. Metal continuity over steps in the substrate was tested as a function of deposition temperature. These studies yielded recommendations, regarding the general use of alloy metallization on silicon devices and its specific use in two-level metallization configurations, which include: deposition at temperatures down to 275°C and at evaporation rates of about 0.4 g/min; the use of initial layer thickness down to 0.7 μ; post-deposition processing for aluminum-copper or aluminum-copper-silicon not to exceed 525°C; the addition of 1% silicon to prevent junction penetration; and the addition of 4% copper to lend adequate electromigration resistance and inhibit hillock growth during high temperature processing.     

明胶固定化改性壳聚糖膜的制备与性能表征

用碳二亚胺缩合剂将明胶固定于壳聚糖膜表面,采用傅立叶红外光谱、X射线光电子能谱表征改性膜的结构,结果显示明胶成功固定于壳聚糖膜表面.透光率、吸水率和接触角测试表明,改性膜的透光率最高可达98%左右,能满足角膜修复对透光性的要求.改性后膜的吸水率提高到97.6%,接触角下降到73.4°,亲水性提高.以壳聚糖膜和明胶固定化改性壳聚糖膜为载体培养人成纤维细胞,结果显示细胞在明胶固定化改性壳聚糖膜上的生长情况优于壳聚糖膜,改性膜具有良好的细胞亲和性.这种明胶固定化改性壳聚糖膜有望成为一种角膜修复材料.     

纳米多孔二氧化硅薄膜的制备与表征

以正硅酸乙酯为原料,采用酸/碱两步溶胶 凝胶法、结合匀胶和超临界干燥等工艺在硅片上成功制备了纳米多孔二氧化硅薄膜。适合匀胶的二氧化硅溶胶的粘度范围为 9~15mPa·s;多孔二氧化硅薄膜表面均匀平整,其厚度为400~1000nm;折射率为1.09~1.24;介电常数为1.5~2.5。该多孔二氧化硅薄膜具有三维网络结构,二氧化硅微粒直径为10~20nm。     

碱催化多孔二氧化硅薄膜的制备和性能表征

以水为介质,NH3·H2O为催化剂,丙三醇(C3H5(OH)3和聚乙烯醇(PVA)为添加剂,正硅酸乙脂(TEOS)溶胶 凝胶工艺可制备纳米多孔二氧化硅薄膜。体系的H2O/TEOS>15,TEOS的水解 聚合过程可通过添加剂效应,pH效应等控制。碱催化会使二氧化硅的溶解度增大,也能使二氧化硅胶粒带负电荷,抑制了二氧化硅胶粒之间的聚合长大,而丙三醇与TEOS的水解中间Si(OR)4-x(OH)x结合,抑制其与二氧化硅胶粒的聚合。聚乙烯醇(PVA)能使二氧化硅溶胶具有网状结构,使二氧化硅溶胶易于成膜。该工艺制备的多孔二氧化硅薄膜具有纳米多孔结构。其Vicker硬度在600～800N/mm2,热导率<0.2W·m-1K-1。     

纳米多孔二氧化硅薄膜的制备及性能

以N(C_8H_(15))_4~+OH~-为催化剂,用正硅酸乙脂(TEOS)溶胶-凝胶工艺制备出纳米多孔二氧化硅薄膜。体系的H_2O/TEOS>25,强碱催化使二氧化硅的溶解度增大并使二氧化硅胶粒带负电荷,抑制了二氧化硅的聚合。丙三醇与TEOS的水解中间体Si(OC_2H_5)_4-x(OH)_x及二氧化硅胶粒Si_xO_y(OH)_z~(+n)表面Si-OH形成氢键,抑制了二氧化硅的聚沉。聚乙烯醇(PVA)使粒状二氧化硅溶胶具有网状结构,易于成膜。薄膜由致密结构转化为均匀纳米多孔结构是构成薄膜的二氧化硅胶粒在热处理时聚集和塑性形变的结果。多孔二氧化硅薄膜的折射率为1.27～1.42,介电常数为1.578～2.016,热导率为0.2W/(m·K)。