High efficiency solar cells require large surface layers as acceptor [1], Nanoporous titanium dioxide film is an optimun choice for that purpose. For instance, porous titanium dioxide film of one micrometer thickness, prepared by colloidal chemistry, has a porous surface whose area is 100 times larger than the surface of a compact planar film. Obviously, accessibility to surface and crystal phase of the titanium dioxide are of prime importance. In this work, we characterize nanoporous titanium dioxide membranes on Si substrate by means of high-resolution transmission electron microscopy and electron diffraction.

Colloidal TiO2 sols were prepared by a wet chemical method [2]. The resulting colloidal TiO2 sol was autoclaved in a titanium autoclave for 12h at 230°C. A portion of the autoclaved sol was concentrated under vacuum at 30°C until a concentration of 20% TiO2 (by weight) was reached. 40% (by weight of Ti02) carbowax was added to this paste and stirred over night at room temperature.

Spectrum imaging, where a complete spectrum is acquired at each pixel in an image, is potentially a very powerful technique for the characterization of materials. The primary challenge to overcome is to extract all of the relevant information from what are typically large data sets that cannot be readily visualized in their entirety. For energy-dispersive X-ray (EDX) spectrum images, simple mapping has typically been done. In this work, the application of multivariate statistical analysis (MSA) to the characterization of a metal/alumina braze by SEM-EDX spectrum images is described.

The braze characterized in this work joins polycrystalline alumina and a copper-silver eutectic alloy containing some titanium (an ‘active’ metal). The specimen geometry consisted of a sandwich of two pieces of alumina, two braze layers and a Kovar (primarily Fe, Ni and Co) filler layer in the middle. The entire assembly was heat-treated to bond the interfaces and then a polished cross-section was prepared.

The large number of minor elements present in geological specimens and nuclear waste materials, can make TEM/EDS analysis of such samples troublesome. With a parallel detector such as the Gatan PEELS 666, the second difference technique has been shown to be effective at removing the channel-to-channel gain variation [1]. As spectroscopy performed with the Gatan Imaging Filter (GIF200) averages over a 2D array, gain variations are minimal; however, the second-difference technique selectively enhances the high frequency features such as the “white line” absorption edges, particularly of rare earth elements (REE) and transuranics (TRU). The second difference method may thus still have merit with the GIF200. A script was created within the controlling software program (DigitalMicrograph ™) which permitted second difference acquisition [2]. The Spectroscopy Package was also modified with ResEdit and the required values were added to the Global Tags to enable easy application of the second difference routine.

Ceramic materials are widely studied for their high temperature structural applications. In many crystalline ceramics the range of solid solution decreases with temperature and thus precipitation of a second phase occurs. Thus, ceramics can be hardened by precipitation of second phases. However little is known regarding the effect of precipitation and nanocrystalline grain structure in the ductility of ceramic materials. On the other hand, oxide ceramics are under intense-investigation for their technological advantages in magnetization, dielectric response and chemical stability in such diverse uses as magnetic recording media, induction cores and microwave resonant circuits. This investigation has been undertaken to produce, characterize and measure the properties of ceramics that can be hardened by precipitation. The selected systems include Fe(1-x)O-Fe3 and MgO MgFe2O4. Mechanical milling is used to produce nanocrystalline ceramic oxides in the systems Fe(1-x)O-Fe3 and MgO-MgFe2O4 The mechanically alloyed powders are consolidated by means of spark plasma sintering (SPS) at temperatures ranging from 673 K to 1273 K and a pressure varying from 500 to 50 MPa in vacuum.

The equilibrium condition for a liquid droplet in contact with a smooth, homogeneous, isotropic, non-deformable surface is given by the celebrated Young-Dupre equation1. This equation is based on the balance of the horizontal forces acting on the droplet. The idealised assumptions involved in arriving at the equation are seldom met in real experiments. Recently, Saiz et al have discussed the case of ridging of the solid at the three phase boundary (solid-liquid-vapour boundary) as a requirement for a stable three-phase co-existence. The wetting of anorthite on. sapphire substrates of different orientations have been studied earlier. In the present study, the wetting of anorthite liquid on m-plane of sapphire has been studied. The m-plane of sapphire is known to reconstruct in to two sets of facets and thus provides an interesting opportunity to study the wetting of liquid on a nonsmooth surface which contains linear patches with different surface energies.

There is currently an intensive effort to develop large-scale semiconductor nanowire or nanotube materials, such as Si and silicon oxide SiOx (l<x<2), with the uniform wide range of sizes up to 30nm, which would open us new opportunities in semiconductor and catalysis industries but is difficult to achieve at present. Up to our knowledge, the detailed study on macroscopic synthesis of aligned silicon oxide nanostructures with about 30nm diameter has not been carried on yet.

The ordered nanochannel-array anodic alumina were prepared via the anodization of aluminum textured pattern on the surface in a 3% oxalic acidic solution under the constant-voltage condition. It is about 6 μm and contains ordered cylindrical pores with the uniform diameter of 20-30nm and almost perpendicular to the film surface. The aligned silicon oxide nanostructures were prepared on this anodic alumina using a sol-gel method.

For sol aged at room temperature and dipped for lmin., nanowires are formed in a shorter period of aging time; while nanotubes are synthesized in a longer time (above 23 days).

Conical whiskers of layered compounds such as graphite and hexagonal boron nitride (h-BN)2 are interesting materials because their conical morphology results from the introduction of a local topological defect at the cone apex. In the honeycomb array characteristic of graphite and h-BN basal planes, this topological defect is thought to be a non-hexagonal ring (e.g. a pentagon or a square). These defects are known to form the basis of curved nanostructures like fullerenes and buckytubes. Therefore a comparison of their occurrence in two systems known to harbour nanostructures is worthy of study.

The defect structure at the apex of co-produced carbon and boron nitride whiskers was investigated by analytical transmission electron microscopy (TEM). The instrument used was a field-emission JEM3000F high-resolution electron microscope, equipped with a parallel electron energy loss spectrometer (EELS).

Ordered assembly of hollow structures of silica and carbon have drawn much attention recently because of their applications in low-loss dielectrics, catalysis, filtering and photonics. The structure is ordered on the length-scale of the template spheres and the pore sizes are in submicron to micron range. Alternatively, ordered porous silica with much smaller pore sizes in nanosize range (< 30 nm), produced deliberately by introducing surfactant, has also been processed, in which the porosity is created by co-polymers. In this research, a new silica nanostructure with double length-scale ordered porosities was processed, one being at the submicron scale of hollow spheres created by a template of polystyrene (PS), and the other at nano-scale created by self-assembled co-polymers.

Typical processing route includes three steps. Firstly, the ordered template of PS was created. The as-received PS with mean particle size of 203 nm was used as the raw material.

Recent innovations in materials chemistry have allowed the preparation of “hierarchical” ceramic and polymer materials that possess features on several different size scales. One of the newest hierarchical materials are ceramics that exhibit a three-dimensional ordered array of half-micron voids. These macroporous structures are synthesized from a liquid ceramic precursor and a polymer colloidal crystal template. This template is extracted by either thermal or chemical methods leaving a structure such as the porous zirconia particle shown in Fig. 1. The final structure of these materials may be thought of as the opposite of opal: the spheres here are the voids. Ordered arrays of dielectric material like these could potentially be used as photonic crystals that interact with visible light. For the microscopist, these materials create new opportunities to study interrelated aspects such as templating, crystallization, and phase transformations.

Transmission electron microscopy (TEM) was carried out on a Philips CM30 TEM equipped with a LaB6 filament and operating at 300 kV.

High resolution electron microscopes with field emission sources opened the possibility to investigate solids on a 100 pm range. Either electron holograpy can be applied or an information limit that may even extend into a region below 100 pm can be exploited to reach this goal [1]. However, lens aberrations such as the three-fold astigmatism often complicate an image interpretation in the 100 pm range or even make it impossible [2]. On the other hand, there is growing need to understand physical processes at a mono-atomic level in order to further develop artificially structured materials such as nano-crystals, ceramic coatings or semiconductors. Commonly, such materials contain light elements like C, N, or O with bond lengths that are shorter than a typical 180 pm point resolution of a high resolution, electron microscope. The carbon-carbon distance of 150 pm is the shortest bond length value in crystalline solids. Moreover, any projection of a diamond lattice along a low index zone axis for lattice imaging leads to a reduced C-C distance.

An oxidation resistant interfacial layer between the fiber and the matrix is important for prolonged use of ceramic-matrix composites (CMC). The interface layer has to be chemically compatible and stable in high temperature oxidizing environments. At present various oxide based interface layers in CMC are being considered. One candidate is porous interfaces. Zircon has good thermomechanical stability with SiC and mullite, and resists pore coarsening, so it is of interest as a porous interface materials.

Ethanolic zirconia and silica precursors, complexed with polyelectrolytes to form fugitive carbon for porosity were doped with vanadium. These were used to continuously coat the 3M Nextel 720™ alumina-mullite fibers. These fibers were heat-treated in-line in argon at 1000-1300°C, with the aim of finding heat-treatment conditions that would convert the zirconia, silica, and polyelectrolyte into a fine mechanical mixture of zircon and carbon.

Microanalysis has proved crucial in developing thermal-sprayed metal coatings on the surface of reinforced concrete to serve as anodes in impressed current (ICCP) and galvanic (GCP) cathodic protection systems and in understanding their long-term performance. Corrosion of reinforcing bar in concrete bridges is the primary cause of structural deterioration in high chloride environments such as coastal locations and colder climates where roads are deiced with salt. Over 40 pet of more than 500,000 bridges surveyed in the U.S. are in need of repair or rehabilitation. Cathodic protections is the most effective method of mitigating the effects of corrosion due to chloride contaminated concrete. While a young technology, consumable thermal sprayed zinc anodes (see Figure 1 for a schematic of the process) totaling over 40,000 m2 (430,00 ft2) have been installed on the Oregon coast, primarily on the Depoe Bay, Yaquina Bay, and Cape Creek bridges.

Lead zirconate titanate (PZT) is a perovskite-staictured material which is ferroelectric over most of the solid solution and which exhibits a range of electrical and electromechanical properties depending on the Zr/Ti ratio. Thin film PZT is currently being developed for piezoelectric actuators, ferroelectric memory devices and pyroelectric detectors. The ferroelectric properties and microstructures of the PZT films depend upon numerous processing parameters.In this research, sol-gel PZT films crystallized by rapid thermal annealing at 700°C for 30 seconds were investigated. A modification of the procedure described by Budd, Dey and Payne was utilized for the solution preparation. The electrodes/substrates which have been used for the deposition of PZT are Pt/Ti/SiO,/Si. The approximate thicknesses of Pt, Ti and SiO2 layers are 150 nm, 20 nm and 1000 nm, respectively. Transmission electron microscopy (TEM) was used to reveal the microstructure of the films, including the interfacial characteristics, grain sizes and domain structures. Cross sectional specimens were prepared by the following procedures.

Post-deposition ion implantation of boron nitride (BN) films is to be considered as a powerful method for improvement of adhesion between films and substrates and reduction of compressive stresses, which usually accompany the growth of cubic BN.

The goal of this investigation is microcharacterization of as-deposited and ion-implanted BN films to better understand effect of ion implantation on microstructure of the films and film/substrate interface. High Resolution TEM (HF-2000 with field emission gun) has been utilized because of nanocrystalline dimensions of both cubic (c-) and hexagonal (h-) BN phases.

BN films have been deposited on (100) oriented Si substrates by magnetically enhanced activated reactive evaporation2. Plasma source ion implantation has been performed to make surface modifications and to improve the adhesion of the films. X/S specimens for TEM and HRTEM have been prepared in a routine manner, using G-1 epoxy for coupling the specimens, Dimpler VCR D500I, and Gatan Precision Ion Polishing System for final thinning.

Recently, considerable efforts have been made in developing a fabrication procedure for YBa2 Cu3O7-δ superconducting films on a metallic substrate tape for electrical power applications. The central issue is to develop a method, which can produce the tape in sufficiently long lengths at a commercially viable cost. One possible approach is the so-called BaF2 post-deposition annealing process, which involves deposition of an unreacted mixture of a BaF2 -Y-Cu-O layer on a substrate by electron beam evaporation method, followed by heat-treatment of the layer in a mixed-gas atmosphere of a low partial pressure O2, saturated H2 O, and N2 . To fabricate thick and long films, it is important to understand the effects of the heat-treatment parameters on the. structure and the properties. Here, we report our structural analysis of the films annealed at different temperatures.

The films annealed at 725°C, 750°C and 800°C have a similar phase assemblage which are composed ofYBa2 Cu3O7-δ and Y2O3, CuO and Ba-Ti-Sr-O precipitates, as shown in fig. la.

Nanocrystalline bulk Ni processed by inert gas condensation of powders followed by compaction has shown impressive mechanical properties with strength values as high as 50% of the theoretical shear strength. However, the process of warm compaction required for densification often leads to grain growth, and flaws in the microstructure. In this study, thin films of nanocrystalline Ni were processed by magnetron sputtering to bypass the compaction process and achieve a microstructure with very narrow grain size distribution. This paper presents the grain size distribution and other microstructural features of nanocrystalline Ni films.

Ni films were grown on Si and NaCl substrates, using argon plasma generated with the help of a plasma d.c. magnetron source equipped with a Ni target of 99.99% purity. The target power used was 200 W and the argon pressure was maintained at around 6 millitorr during deposition. A pulsed dc negative bias of 0 or 100 V was applied on the Si substrate.

There has been a significant interest in the development of dispersion-hardened aluminum for many years for high specific strength and modulus. Such materials are usually processed by powder or ingot metallurgy routes. In this study, Al3 Ti dispersion hardened Al was obtained by annealing Al-Ti multilayers. Al-Ti multilayered films have been characterized in the past by observing the structure of the layers, as well as tensile properties and hardness. This paper reports the structure of Al-Ti multilayers and the evolution of matrix and dispersoid microstructure on annealing.

The Al-Ti multilayered structures were prepared by magnetron sputtering using Al and Ti as targets and either Si (100) or NaCl as substrates. The bi-layer thickness was maintained around 16 nm with Ti constituting 12% of the total. The substrate was alternately moved below the Al and Ti targets for the purpose of deposition. The as-deposited film on the substrate and NaCl salts were annealed at 400°C for periods between 1 and 24 h in a vacuum (10−5 torr) furnace.

Thermal spray of carbide coatings with high hardness and corrosion resistance onto steel substrates has technological importance. The adhesive strength is greatly effected by the interfacial impurities. Low porous and good quality 200 μm thick 86WC10Co4Cr coatings on 4140 steel are obtained by thermal spray methods using SC-HVOF gun at Cooper Oil Tools, Houston, TX. A Carl Zeiss DSM942 SEM with 3.5 nm resolution at 30 keV and Kevex LPX1 Super Dry Quantum Si(Li) Detector with < 145 eV resolution for Energy Dispersive X-ray Spectroscopy (EDXS) were used to study the elemental distribution across the interface. Fig. 1 shows the SEM micrographs of the interface between 86WC10Co4Cr thermal spray coating and 4140 steel substrate. The anchor patterns seen at the interface are believed to improve the adhesive qualities between the coating and the substrate.

ITO films on PET in combination with ITO films on glass substrates are extensively used in Touch Panel Displays fabrication. Main properties of interest for these systems are high optical transmittance ∽95%, low resistivity ∽10−3 Ωcm, coupled with uniform and stable sheet resistivity demanded for long term use.

The goal of this investigation is to understand relationship between microstructure and electrical/optical properties of ITO films on PET and glass substrates as a function of pre- and postdeposition annealing parameters.

ITO films of ∽60 nm thick have been deposited by radiofrequency magnetron sputtering. This method can be applied over a wide range of substrate temperatures. This is essential for plastic substrates such as PET. Regions of good and poor conductivity have been identified for TEM analysis and Analytical Electron Microscope (Philips 400 EM), equipped with light element Noran Instrument Energy Dispersive X-ray Spectrometer (EDXS) have been utilized.

Vanadium dioxide (VO2 ) exhibits a reversible semiconductor-to-metal phase transition around 341 K. The low temperature monoclinic P21 /c structure transforms into the tetragonal P42 /mnm rutile structure. The associated sharp changes in optical and electrical properties are used in various thin film switching devices. The present paper describes a study on the optical and structural changes during the synthesis of VO2 thin films using Infra-Red (IR) reflectance spectroscopy and Transmission Electron Microscopy (TEM).

The synthesis was derived from a sol-gel process by Guzman et al. Solutions of vanadyl isopropoxide (VO(OC3 H7)3 ) in n-propanol were spin-coated on a Si wafer provided with 300 nm thermal oxide. Subsequently, the wafer was transferred to an oven and heated to 773 K in a reducing H2/N2 atmosphere using a heating rate of 5 K/min. After a variable time (Δt) at 773 K, the samples were cooled down to room temperature.

Figure 1 shows the IR reflectance of thin (∽50 nm) VOx films on oxidised Si at λ,=3 μm and an angle of incidence ϕ of 30°.