scholarly journals Characterization of γ′ Precipitates in Cast Ni-Based Superalloy and Their Behaviour at High-Homologous Temperatures Studied by TEM and in Situ XRD

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2397 ◽  
Author(s):  
Łukasz Rakoczy ◽  
Ondrej Milkovič ◽  
Bogdan Rutkowski ◽  
Rafał Cygan ◽  
Małgorzata Grudzień-Rakoczy ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Matrix Material ◽  
High Volume ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
In Situ Xrd ◽  
Transmission Electron ◽  
The Matrix

In situ X-ray diffraction and transmission electron microscopy has been used to investigate René 108 Ni-based superalloy after short-term annealing at high-homologous temperatures. Current work is focused on characterisation of γ′ precipitates, their volume fraction, evolution of the lattice parameter of γ and γ′ phases and misfit parameter of γ′ in the matrix. Material in the initial condition is characterised by a high-volume fraction (over 63%) of γ′ precipitates. Irregular distribution of alloying elements was observed. Matrix channels were strongly enriched in Cr, Co, W and Mo, whereas precipitates contain large amount of Al, Ti, Ta and Hf. Exposure to high-homologous temperatures in the range 1100–1250 °C led to the dissolution of the precipitates, which influenced the change of lattice parameter of both γ and γ′ phases. The lattice parameter of the matrix continuously grew during holding at high temperatures, which had a dominant influence on the more negative misfit coefficient.

scholarly journals Characterization of Highly Dispersed Rod- and Particle-Shaped CuFe19Ox Catalysts and Their Shape Effects on WGS

Catalysts ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 635
Author(s):  
Lingjuan Ma ◽  
Dawei Han ◽  
Hongbin Ma ◽  
Longgang Liu ◽  
Huichao Guo
Keyword(s):  
X Ray Diffraction ◽  
X Ray ◽  
In Situ Xrd ◽  
Transmission Electron ◽  
Highly Dispersed ◽  
Shape Effects ◽  
Temperature Programmed ◽  
Water Gas

Highly dispersed CuFe19Ox catalysts with different shapes were prepared and further characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), H2 temperature-programmed reduction (H2-TPR), and in-situ XRD. XRD and TEM results showed that the synthesized CuFe19Ox nanoparticles consisted of CuO and Fe2O3, while CuFe19Ox nanorods consisted of CuFe2O4 and Fe2O3. The reduction properties of CuFe19Ox samples were finely studied by H2-TPR, and the phase composition was identified by in-situ XPS, HR-TEM, and surface TPR (s-TPR). In-situ X-ray photoelectroscopy (XPS) indicated that the metallic Cu and Fe3O4 were the main species after reduction. Moreover, s-TPR studies showed that the reduction performance of copper was significantly affected by the shapes of the Fe3O4 supports. Low-temperature water gas shift (LT-WGS) was chosen to characterize the Cu species on the surface. It was found that reduced CuFe19Ox nanorods had no activity. On the contrary, reduced CuFe19Ox particles showed higher initial WGS activity, where the active Cu0 should originate from the reduction of Cu2O at lower temperatures, as confirmed by the s-TPR profiles.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Sol-gel derived Ba(Mg1/3Ta2/3)O3 thin films: Preparation and structure

1997 ◽  
Vol 12 (3) ◽  
pp. 596-599 ◽  
Author(s):  
Ji Zhou ◽  
Qing-Xin Su ◽  
K. M. Moulding ◽  
D. J. Barber
Keyword(s):  
Thin Films ◽  
Annealing Temperature ◽  
Volume Fraction ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Small Grains

Ba(Mg1/3Ta2/3)O3 thin films were prepared by a sol-gel process involving the reaction of barium isopropoxide, tantalum ethoxide, and magnesium acetate in 2-methoxyethanol and subsequently hydrolysis, spin-coating, and heat treatment. Transmission electron microscopy, x-ray diffraction, and Raman spectroscopy were used for the characterization of the thin films. It was shown that the thin films tend to crystallize with small grains sized below 100 nm. Crystalline phase with cubic (disordered) perovskite structure was formed in the samples annealed at a very low temperature (below 500 °C), and well-crystallized thin films were obtained at 700 °C. Although disordered perovskite is dominant in the thin films annealed below 1000 °C, a low volume fraction of 1 : 2 ordering domains was found in the samples and grows with an increase of annealing temperature.

Synthesis of nanostructured metal (Fe, Al)-C60 composites

2010 ◽  
Vol 1276 ◽  
Author(s):  
I. I. Santana García ◽  
V. Garibay Febles ◽  
H. A. Calderon
Keyword(s):  
Raman Spectroscopy ◽  
Mechanical Milling ◽  
Volume Fraction ◽  
High Volume ◽  
X Ray Diffraction ◽  
Nanostructured Composite ◽  
Plasma Sintering ◽  
Transmission Electron ◽  
Show Evidence ◽  
Spark Plasma

AbstractComposites of M-2.5 mol. % Fullerene C60 composites (where M= Fe or Al) are prepared by mechanical milling and Spark Plasma Sintering (SPS). The SPS technique has been used to consolidate the resulting powders and preserve the massive nanostructure. Results of X-Ray Diffraction and Raman Spectroscopy show that larger milling balls (9.6 mm in diameter) produce transformation of the fullerene phase during mechanical milling. Alternatively smaller milling balls (4.9 mm in diameter) allow retention of the fullerene phase. SEM shows homogeneous powders with different particle sizes depending on milling times. Sintering produces nanostructured composite materials with different reinforcing phases including C60 fullerenes, diamonds and metal carbides. The presence of each phase depends characteristically on the energy input during milling. Transmission Electron Microscopy (TEM) and Raman Spectroscopy show evidence of the spatial distribution and nature of phases. Diamonds and carbides can be identified for the sintered Fe containing composites with a relatively high volume fraction.

scholarly journals Structural characterization of Fe–C coatings prepared by reactive triode-magnetron sputtering

2010 ◽  
Vol 25 (9) ◽  
pp. 1859-1869 ◽  
Author(s):  
Isabelle Jouanny ◽  
Valérie Demange ◽  
Jaafar Ghanbaja ◽  
Elisabeth Bauer-Grosse
Keyword(s):  
Magnetron Sputtering ◽  
Gas Flow ◽  
Carbon Matrix ◽  
Grazing Incidence ◽  
X Ray Diffraction ◽  
Electron Microscopies ◽  
Transmission Electron ◽  
Electron Energy Loss

Fe1–xCx coatings were synthesized by triode magnetron sputtering of an iron target in a methane/argon atmosphere with a large range of composition (x = 0.3 to 0.6 ± 0.06). Film surfaces were characterized by grazing incidence x-ray diffraction, scanning and transmission electron microscopies, and electron energy loss spectroscopy, to study effects of the variation of the methane gas flow rate on their structural properties. The coatings were constituted of the ε-Fe3C carbide (x = 0.3 and 0.36), in which carbon atoms are in octahedral sites, and of nanocomposite structure constituted of disordered and crystalline carbide nanograins embedded in a carbon matrix made of an amorphous and poorly crystallized graphenelike material (x = 0.55 and 0.60). In situ annealing of the nanocomposite Fe0.45C0.55 coating led to the formation of carbides θ-Fe3C and Fe7C3 (with carbon atoms in prismatic sites) and C-rich cubic carbide possibly related to the τ2-Fe2C7 compound.

The Recognition of Amorphous Silica in Indurated Soil Profiles

Clay Minerals ◽  
1993 ◽  
Vol 28 (3) ◽  
pp. 461-474 ◽  
Author(s):  
Balbir Singh ◽  
R. J. Gilkes
Keyword(s):  
Amorphous Silica ◽  
Silica Content ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
The Matrix ◽  
Clay Matrix ◽  
Secondary Silica ◽  
Xrd Techniques

AbstractSilica-indurated subsurface horizons of an in situ lateritic profile in semi-arid western Australia were investigated using a range of electron-optical and X-ray diffraction (XRD) techniques. These indurated materials were compared with underlying non-indurated pallid zone material. The secondary silica content of the indurated horizons, as determined by electron microprobe analysis, varied from 8 to 33%. Quantitative digital images for secondary silica, generated by mathematical manipulation of digital Si and AI-Kα: images, showed that kaolinite pseudomorphs after mica contained the lowest amounts of secondary silica, with the highest amounts being present in the inter-pseudomorph clay matrix. Variations in the amount of silica in the matrix are considered to reflect variations in the initial porosity of the clay matrix. Such variations may arise from differences in the Al/Si ratio of parent minerals. Transmission electron microscopy (TEM) showed that amorphous silica adhered to the (001) face of kaolinite crystals. The secondary silica could not be detected by either standard or differential XRD procedures.

Synthesis and characterization of organic–inorganic poly(3,4-ethylenedioxythiophene)/MoS2 nanocomposite via in situ oxidative polymerization

2006 ◽  
Vol 21 (1) ◽  
pp. 112-118 ◽  
Author(s):  
A. Vadivel Murugan ◽  
Mathieu Quintin ◽  
Marie-Helene Delville ◽  
Guy Campet ◽  
Annamraju Kasi Viswanath ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Oxidative Polymerization ◽  
X Ray Diffraction ◽  
Rechargeable Lithium Batteries ◽  
X Ray ◽  
Transmission Electron ◽  
Basal Distance ◽  
New Type

Here we demonstrate the synthesis of a new type of layered poly(3,4-ethylenedioxy- thiophene) (PEDOT)/MoS2 nanocomposite via flocculation of delaminated MoS2 with subsequent in situ oxidative polymerization of 3,4-ethylenedioxythiophene. The resulting nanocomposite was characterized by Fourier transform infrared spectroscopy, powder x-ray diffraction, x-ray photoelectron spectroscopy, thermal analysis, transmission electron microscopy, and four-probe electrical conductivity measurements with respect to temperature. X-ray diffraction results indicated that the exfoliated MoS2 and PEDOT are restacked to produce a novel nanoscale composite material containing alternate nanoribbons of PEDOT in between MoS2 with a basal distance of ∼1.38 nm. The nanocomposite, which could be used as a cathode material for small power rechargeable lithium batteries, has also been demonstrated by the electrochemical insertion of lithium into the PEDOT/MoS2 nanocomposite, where a significant enhancement in the discharge capacity is observed, compared to that of respective pristine molybdenum disulfide.

Microstructural Characterization of In Situ Reaction TiB2/Zn-30Al-1Cu Composites Prepared by Spray Deposition Process

2014 ◽  
Vol 1015 ◽  
pp. 688-691 ◽  
Author(s):  
Feng Wang ◽  
Qiang Zhang ◽  
Bai Qing Xiong ◽  
Yong An Zhang ◽  
Hong Wei Liu ◽  
...  
Keyword(s):  
Spray Deposition ◽  
Microstructural Characterization ◽  
Deposition Process ◽  
Deposition Technique ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

An innovative spray deposition technique has been applied to produce in situ TiB2/Zn-30Al-1Cu composites. The microstructures of the spray-deposited composite were studied using scanning electron microscopy, transmission electron microscope and X-ray diffraction. The results have shown that the TiB2particulates are formed in the microstructure. It was found that the TiB2particles were distributed in Zn-30Al-1Cu matrix uniformly, and the TiB2particles are about 2μm in size.

Effect of TiC Particles Volume Fraction on the Mutual Diffusion of Al and Mg during Fabrication of Al-4.5wt%Mg/TiC via Mechanical Alloying Process

2012 ◽  
Vol 326-328 ◽  
pp. 141-146 ◽  
Author(s):  
O. Ozhdelnia ◽  
Ali Shokuhfar
Keyword(s):  
Mechanical Alloying ◽  
Volume Fraction ◽  
Weight Ratio ◽  
Lattice Parameter ◽  
Mutual Diffusion ◽  
X Ray Diffraction ◽  
The Matrix ◽  
Elemental Diffusion ◽  
Diffraction Patterns ◽  
Composite Samples

In this work the effects of volume fraction at different milling times and impact forces, defined as the ball-to-powder weight ratio (BPR), on the elemental diffusion during mechanical alloying process of Al-4.5wt%Mg/TiC composite were evaluated and compared with the TiC free samples (Al-4.5wt%Mg alloy). X-ray diffraction patterns of the monolithic and composite samples imply the fact that a higher level of mutual diffusion of constituents, Al and Mg, happened in the matrix in the presence of TiC particles. This effect of the reinforcing particles can be attributed to the increased densities of dislocation and vacancy caused by the presence of TiC particles within the matrix-giving rise to increasing the micro-strain, lattice parameter and decreasing the crystallite size. Scanning electron microscopy (SEM) was used not only to study the morphology of the powders but also to show the fact that the TiC powders were distributed during MA process. The TEM and HRTEM results showed that powder produced in this work has a nanosize.

scholarly journals Effect of Silver (Ag) Addition on the Forming Of Y-247 Superconductors (Y2Ba4Cu7O15-?) using Wet Mixing Method

2019 ◽  
Vol 20 (1) ◽  
pp. 11
Author(s):  
A.A. Made Wisnu Wijaya Putra ◽  
W. G. Suharta ◽  
P. Suardana
Keyword(s):  
Volume Fraction ◽  
Lattice Parameter ◽  
Synthesis Process ◽  
X Ray Diffraction ◽  
Ag Addition ◽  
X Ray ◽  
Mixing Method ◽  
Parameter Values ◽  
Scanning Electron

Superconductor Y-247 (Y2Ba4Cu7O15-?) with adding silver (Ag) by using the wet-mixing method has been done. The synthesis process was carried out by calcination at 600o C for 3 hours and sintered at 925o C for 10 hours. Variations in the increase in the addition of Ag used were Ag0.05, Ag0.1, Ag0.15 and Ag0.2. Characterization of X-Ray Diffraction (XRD), showed an increase in the addition of Ag resulting in a decrease in the volume fraction, where the volume fractions obtained consecutive were 55.0%, 51.3%, 50.9% and 46.3%. Increasing the addition of Ag results in an increase in the lattice parameter values in the direction of the a axis which is 3.8247 Å, 3.8291 Å, 3.8292 Å, 3.8293 Å, decreasing the lattice parameter values in the b axis direction which is 3.8426 Å, 3.8415 Å, 3.8409 Å, 3.8383 Å and decreasing the lattice parameter values in the direction of the c axis are 49.2174 Å, 49.2022 Å, 49.1881 Å, 49.1761 Å. Analysis of the results of the characterization of Scanning Electron Microscopy (SEM), the particle size obtained was 225.47 nm, 202.88 nm, 190.68 nm and 172.22 nm.

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