Showing papers on "Texture (crystalline) published in 1994"
TL;DR: In this article, a method was developed that yields the residual stress, the orientation distribution coefficients, the average crystallite dimension, the microstrain, and the crystal structure parameters from x-ray diffraction data in a single step procedure.
Abstract: A method is developed that yields the residual stress, the orientation distribution coefficients, the average crystallite dimension, the microstrain, and the crystal structure parameters from x‐ray diffraction data in a single‐step procedure. To this end, a general approach is introduced that combines the equations of micromechanics with the harmonic description of texture. All relationships are cast into a Rietveld‐like format, which incorporates a microstructure model derived from line‐broadening methods. In this manner, data collected over the whole x‐ray‐diffraction pattern at different tilting of the sample can be fitted directly. The associated fitting parameters are the crystal structure and microstructure, the texture coefficients, and the micromechanical properties and fields.
310 citations
TL;DR: In this paper, the influence of nitrogen impurities in CH4/H2 gas mixtures on the structure and morphology of polycrystalline diamond films prepared by microwave plasma assisted chemical vapor deposition was studied.
Abstract: We have studied the influence of nitrogen impurities in CH4/H2 gas mixtures on the structure and morphology of polycrystalline diamond films prepared by microwave plasma assisted chemical vapor deposition. The nitrogen concentration in the process gas was varied between 1 and 1000 ppm. Optical emission spectroscopy was applied to detect the nitrogen in the plasma via emission from CN radicals. The morphology and texture of polycrystalline films prepared with various N2 impurity levels and CH4 concentrations in the range 0.5%–2% was investigated using scanning electron microscopy and x‐ray texture analysis. For the films prepared with low methane concentrations (e.g., 0.5%) only a minor influence of the nitrogen was observed. However, most interestingly, for higher methane concentrations (1%–2%) the addition of small amounts of nitrogen turned out to have a tremendously beneficial effect on the film morphology and structure. Films prepared without additional nitrogen are of nanocrystalline structure and of...
233 citations
TL;DR: In this article, a molecular model consistent with theoretical predictions on how to connect cylindrical tubule segments is provided, which is probably caused by the occurrence along the helix of pairs of pentagon-heptagon carbon rings in the hexagonal network.
Abstract: The growth of micron-size carbon fibres from thermal decomposition of hydrocarbons catalyzed by a metal has been widely studied. Coil-shaped fibres often grow among straight or twisted filaments. Their internal structure has not been studied in detail as yet. In the present work, the thermal cracking of acetylene on Co nanoparticles dispersed on porous silica has produced relatively well graphitized hollow nanotubules, including straight filaments and regular helices. The small diameter of the coiled tubules and the absence of an amorphous coating allowed a determination of their texture by transmission electron microscopy (TEM). The coiled tubules consist of regularly polygonized, coaxial graphene tubes whose angular bends are aligned. The bends are probably caused by the occurrence along the helix of pairs of pentagon-heptagon carbon rings in the hexagonal network. Such a structure was recently predicted to be a thermodynamically stable topology for helical, single-sheet carbon tubes. A molecular model, consistent with theoretical predictions on how to connect cylindrical tubule segments, is provided.
210 citations
TL;DR: The microstructure of low resistivity (∼ 2 × 10−4 Ω cm) Sn-doped In2O3 (ITO) thin films prepared by multipass d.c. magnetron sputter deposition with an ITO (10 wt.% SnO2) target onto soda-lime glass substrates was investigated using plan-view and cross-sectional transmission electron microscopy (TEM) and X-ray diffraction as discussed by the authors.
196 citations
TL;DR: In this paper, the major components of the texture of pancaked austenite are the Bs {110} and Cu {112}, and these give rise, respectively, to the {332} and {113} components in the transformation product.
Abstract: During the hot rolling of steels, the parent austenite phase develops a crystallographic texture. As a result, the material after transformation (ferrite, martensite, acicular ferrite, or bainite ) also acquires a texture which is related in a precise way to the texture of the parent material. The major component of the transformation texture derived from recrystallized austenite is the {001} , which originates from the cube {100} component of the parent texture. The major components of the texture of pancaked austenite are the Bs {110} and Cu {112} , and these give rise, respectively, to the {332} and {113} components in the transformation product. The Goss {110} , Goss/Bs {011} , Bs/S {168} , S{123} , and S/Cu {236} orientations in the deformed austenite also contribute to the formation of the overall transformation texture. Since more than one parent γ orientation can transform into the same bcc orientation, it is sometimes impossible to determine, unambiguously, the origin of particular transformation texture components in the parent γ texture. The intensity of the overall transformation texture can be increased by the addition of Nb, Ti and V to steel, by giving large reductions during controlled rolling, and by using lower finishing temperatures during processing. Among the transformation texture components, the {332} is the most beneficial from the point of view of achieving good deep drawability and improved strength and toughness. The presence of substitutional solutes such as Mn, Ni, Cr or Mo, finer austenite grain sizes and faster cooling rates during transformation increase the intensity of the {332} component. By contrast, the intensity of the {113} component remains relatively insensitive to the above factors.
188 citations
TL;DR: In this paper, the effects of the activating gas on porosity and mechanical properties of activated carbon fibres have been analyzed and the results have been interpreted considering the different behaviour of the two molecules (CO2 and steam) involved in the reaction in the narrow microporosity.
129 citations
TL;DR: In this article, a Ferroelectric BaTiO3 thin film with a thickness of 0.58 µ m exhibited a dielectric constant of 1000, remanent polarization of 8 µ C/cm2 and coercive field of 30 kV/cm.
Abstract: Ferroelectric BaTiO3 thin films were prepared on Pt(111)/ SiO2/Si(100) substrates at 650° C by the sol-gel method. Film thickness could be varied by repeating a dip coating/heating cycle. The texture of the BaTiO3 thin films became more dense and homogeneous when the film thickness increased. The crystalline thin films showed microstructure with grains as small as 20–30 nm. The dielectric properties could be measured for films thicker than 0.25 µ m. With increasing film thickness, the dielectric constant and remanent polarization increased and the coercive field decreased. Loss tangent of the thin films was independent of the film thickness. BaTiO3 thin film with a thickness of 0.58 µ m exhibited a dielectric constant of 1000, remanent polarization of 8 µ C/cm2 and coercive field of 30 kV/cm.
120 citations
TL;DR: In this article, the effects of thin Ti, TiN, or Ti/TiN underlayers on the development of the crystallographic texture and the grain structure are explored.
Abstract: The effects of thin Ti, TiN, or Ti/TiN underlayers on the development of the crystallographic texture and the grain structure are explored. Metal layers ∼0.5 μm in thickness of Al‐0.5Cu or of Cu are deposited on these underlayers and on amorphous SiO2 as a reference. A strongly textured underlayer such as Ti〈0002〉 or Ti〈0002〉/TiN〈111〉 induces a similarly strong 〈111〉 texture in the AlCu. In copper with 〈111〉, 〈200〉, and random texture components, an underlayer induces a stronger 〈111〉 component compared to an analogous film deposited on SiO2. A nearly random texture in TiN significantly weakens the texture in subsequent metal films. Grain size distributions in all AlCu films are monomodal reflecting a process of normal grain growth. The grain size distribution for Cu sometimes deviates from lognormal. The bimodal distribution implies that grain growth is abnormal even though the median grain size does not exceed a low multiple of the film thickness.
109 citations
TL;DR: In this article, the effect of growth parameters on the growth rate and crystal texture of the dioxide thin films was studied and the results showed that the films were transparent and highly uniform with only small thickness variations.
104 citations
Patent•
09 Mar 1994
TL;DR: In this paper, an extrusion laminates of incrementally stretched nonwoven fibrous webs (8) and thermoplastic films (3) are made. And a web of fiber ends extending outwardly from both web surfaces for bonding with the extruded thermoplastics and to provide a soft fibrous texture to the laminate.
Abstract: Extrusion laminates of incrementally stretched nonwoven fibrous webs (8) and thermoplastic films (3) are made. A web of spun bonded fibers (22) is incrementally stretched to provide fiber ends (20) extending outwardly from both web surfaces for bonding with the extruded thermoplastic film (3) and to provide a soft fibrous texture to the laminate.
101 citations
TL;DR: In this article, the effect of Sb doping on the growth rate, crystal texture and electrical and optical properties of tin dioxide thin films was studied using Spectrophotometry, secondary ion mass spectrometry, X-ray diffraction and electron spectroscopy for chemical analysis.
TL;DR: In this article, a model for the formation of the crystallographic texture of sputterdeposited Cr thin films is proposed, and a set of experiments has been carried out to test the model.
Abstract: Although it is well known that Cr underlayers sputter deposited on glass or NiP/Al substrates have either the (002) or (110) textures, the mechanism of the formation of the crystallographic textures is not clear. A model is proposed for the formation of the crystallographic texture of sputter‐deposited Cr thin films. A systematic set of experiments has been carried out to test the model. It was found that the (110) texture, which is usually found in Cr thin films deposited on substrates without preheating, can form at elevated temperatures (250 °C) when deposited at low Ar pressure or by applying substrate bias. The initial stage of the texture formation was also investigated by using very thin Cr films. It was found that the (002) texture can be initiated directly on the substrate surface, while the (110) texture appears not to form directly on substrate surface, but rather as a result of film growth. The proposed model is consistent with the experimental results.
TL;DR: In this paper, the magnetoresistance effects and film structures have been investigated in [Fe-Mn/Ni-Fe/Cu/Ni−Fe/buffer layer/Si] sandwiches with various buffer layer materials.
Abstract: Magnetoresistance effects and film structures have been investigated in [Fe–Mn/Ni–Fe/Cu/Ni–Fe/buffer layer/Si] sandwiches with various buffer layer materials. The sandwich with Nb, Ta, Ti, Zr or Hf buffer layer has strong (111) texture. Cu, Ag, Au and Cr buffer layers do not cause strong (111) texture. When the sandwich has strong (111) texture, the Ni–Fe layer neighboring the Fe–Mn antiferromagnetic layer is strongly exchange-biased by the Fe–Mn layer, and thus the sandwich shows a high magnetoresistance ratio.
TL;DR: In this article, a hexagonal 2H phase was found in WO 3 films of WSe 2 on quartz in an open tube furnace and the films were investigated by X-ray diffraction, Xray photoelectron spectroscopy, scanning electron microscopy and optical absorption.
TL;DR: In this article, a polycrystalline thin films of tin selenide have been prepared by reactive evaporation at substrate temperatures ranging from 473-600 K to 495-525 K and optical absorption studies indicate that the fundamental absorption starts at 1.21 eV.
Abstract: Polycrystalline thin films of tin selenide have been prepared by reactive evaporation at substrate temperatures ranging from 473–600 K. Crystallites of the films prepared at substrate temperatures below 525 K are randomly oriented, while they have a strong preferred orientation on the substrate surface at higher substrate temperatures. Optical absorption studies indicate that the fundamental absorption starts at 1.21 eV and it is due to an allowed direct transition.
TL;DR: In this paper, the accuracy of a Taylor-type constitutive model and computational procedures for polycrystalline materials in predicting the deformation response of initially pre-textured OFHC copper is evaluated.
Abstract: T he accuracy of a Taylor-type constitutive model and computational procedures for polycrystalline materials in predicting the deformation response of initially pre-textured OFHC copper is evaluated. An approximate procedure for the characterization of the state of pre-textured fcc materials is developed. This procedure, when applied to a pre-textured OFHC copper, produced a characterization of the state of this material which is of reasonable accuracy for engineering purposes. Our mathematical models and procedures use this characterization of the initial state of the pre-textured copper to predict the macroscopic stress-strain behavior, crystallographic texture evolution and macroscopic shape change in subsequent nominally homogeneous and non-homogeneous experiments. The predictions from our mathematical procedures are found to be in good first-order accord with corresponding experimental measurements for this fcc material.
TL;DR: In this article, the authors used the low-incident-beam-angle diffraction technique (LIBAD) for the characterization of thin crystalline coatings and found that the residual stress in the uppermost region of the substrate is influenced by the stress state in the coating.
Abstract: The low-incident-beam-angle diffraction technique (LIBAD) has been developed as a powerful X-ray diffraction tool for the characterization of thin crystalline coatings. The technique can be implemented to determine the residual stress state in thin coatings, their crystallographic texture, by means of the orientation distribution function, and thickness, as well as the stress profile in a coating as a function of depth. As an example, electrodeposited nickel coatings on a copper substrate have been characterized with this technique for thicknesses varying from 0.6 to 3.8 μm. Crystallographic texture and mean residual stress appear to be correlated with the coating thickness. So, for example, the residual stress of the coatings evolves from a low to a high tensile stress with increasing coating thickness. The stress in the uppermost region of the substrate is influenced by the stress state in the coating. The stress profile in the coating was found to be linearly dependent on the information depth.
TL;DR: In this article, the density of oxide core in (Bi,Pb)2Sr2Ca2Cu3OxAg sheathed tape was estimated from Vickers hardness and found to be increased to as high as 93% of the theoretical density with increasing the degree of cold working.
Abstract: The density of oxide core in (Bi,Pb)2Sr2Ca2Cu3OxAg sheathed tape was estimated from Vickers hardness and found to be increased to as high as 93% of the theoretical density with increasing the degree of cold working. During heat treatment, this densification before heat treatment promoted the formation of a strong linked microstructure which is characterized by dense microstructure, a high degree of orientation of oxide crystal and smooth interface between the Ag sheath and oxide core. Consequently, we obtained high values of critical current density: 66 000 A/cm2 at 0 T and 14 500 A/cm2 at 1 T for 77 K.
TL;DR: In this article, the microstructure and magnetic properties of Co/Pt multilayer thin films sputtered onto glass and Si substrates with different surface roughness caused by different methods of substrate preparation.
Abstract: We studied the microstructure and magnetic properties of Co/Pt multilayer thin films sputtered onto glass and Si substrates with different surface roughness caused by different methods of substrate preparation. The microstructure determined by high‐resolution electron microscopy and x‐ray scattering could be correlated to the observed magnetic properties. Better (111) texture and smoother layer structures produced on smoother glass substrate surfaces produced higher uniaxial anisotropy. Coercivity, on the other hand, was enhanced by either pinning of the domain walls caused by substrate surface roughness or stronger columnar structure. Although Si substrates exhibited slightly different roughness under the same preparation conditions, the dependence of magnetic properties on the substrate surface was consistent with the trends using glass substrates.
Journal Article•
TL;DR: In this article, the thermal diffusivity and specific heat of the YBa2Cu3O7-x matrix phase are separated using independently measured data of a Y2BaCuO5 polycrystal.
Abstract: The anisotropic thermal diffusivity α of the highly c-axis-oriented Y–Ba–Cu–O bulk superconducting crystals has been measured quasi-simultaneously with the thermal conductivity κ. The estimated values of the specific heat C by use of α and κ values parallel and perpendicular to the c-direction agreed with each other. In these crystals prepared by the modified melt texture growth (MMTG) method, fine Y2BaCuO5 particles are dispersed in the YBa2Cu3O7-x superconducting matrix phase. Based on a simple model, the thermal diffusivity and the specific heat of the YBa2Cu3O7-x matrix phase are separated using independently measured data of a Y2BaCuO5 polycrystal. The influence of Y2BaCuO5 particles on the thermal properties of the mixed crystals is discussed.
TL;DR: By using a modified bias sputtering technique, biaxially-textured YSZ thin films were fabricated on polycrystalline metal substrate as a buffer layer for deposition of YBCO films as mentioned in this paper.
Abstract: By using a modified bias sputtering technique, biaxially-textured YSZ thin films were fabricated on polycrystalline metal substrate as a buffer layer for deposition of YBCO films. The growth quality of YSZ buffer layers thus obtained was found to determine the texture of subsequently grown YBCO films, which in turn governed the current-carrying capacity of the films. The best films prepared to date gave a T c of 90 K and J c of 3 × 10 5 A/cm 2 at zero field and 77 K, which was one order higher than that of YBCO grown on an untextured YSZ buffer layer. In order to improve the growth quality of the YBCO films, a Pt thin layer was inserted between the YSZ buffer and the Hastelloy substrate. The reason is not yet clearly understood but a Pt underlayer as thin as 20 nm appeared very promising for attaining the desired combination of good transport properties with smooth surfaces in YBCO films.
TL;DR: A considerable body of evidence collected on silver-sheathed conductors heat treated without any additional rolling or pressing (beyond fabrication of the initial composite) has revealed that significant texturing of the Bi-2223 grains occurs as the Bi−2223 formation reaction takes place as mentioned in this paper.
Abstract: A considerable body of evidence collected on silver‐sheathed (Bi,Pb)2Sr2Ca2Cu3O10+δ (Bi‐2223/Ag) composite conductors heat treated without any additional rolling or pressing (beyond fabrication of the initial composite) has revealed that significant texturing of the Bi‐2223 grains occurs as the Bi‐2223 formation reaction takes place. During heat treatment, Bi‐2223 is produced via a reaction between Bi‐2212 and second phases in the core of the composite. As the Bi‐2223 forms, it develops texture by what appears to be a grain growth mechanism. These concurrent processes ultimately result in a well‐textured, single‐phase conductor even when no additional rolling or pressing is done to the initial composite. This observation raises important questions about the relative contributions of the heat treatment and deformation steps to texture development during conventional oxide‐powder‐in‐tube processing of Bi‐2223/Ag composite conductors.
TL;DR: In this article, differently prepared microwave plasma-deposited diamond films with a broad spectrum of morphological and Raman spectroscopic features were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD).
TL;DR: In this article, high-resolution X-ray texture goniometry (HRXTG) was used to improve peak/background ratios and allow for the determination of crystallographic preferred fabrics of small regions.
TL;DR: In this paper, the effects of processing parameters of physical vapour deposition on the microstructure of partially stabilized zirconia (PSZ) thermal barrier coatings have been experimentally investigated.
TL;DR: In this paper, the influence of the calcining temperature on the texture and the crystallization of the solids has been measured by polarization microscopy, and the dyring method on texture is studied through nitrogen adsorption-desorption isotherm analyses.
Abstract: Homogeneous BaTiO3 gels were prepared by hydrolysis and polycondensation reactions between titanium isopropoxide and barium hydroxide in the presence of methoxyethanol, methanol and water. Gel formation mechanisms were investigated by Raman scattering spectrometry. Two during methods are carried out: either in air with a possible formation of barium carbonate or in a vacuum furnace, sheltered from CO2. The influence of the dyring method on texture is studied through nitrogen adsorption-desorption isotherm analyses. A heat treatment is deduced from thermogravimetry and differential scanning calorimetry results. The influence of the calcining temperature on the texture and the crystallization of the solids has been measured. For the first time, the transformation at 900°C from the cubic to the tetragonal form of BaTiO3 has been observed by polarization microscopy.
Metz1
TL;DR: In this article, a series of Pt/Co (111)-oriented multilayer thin films were sputter-deposited under a number of deposition conditions to promote differences in the structure of the films.