Production of Magnesium Titanate-Based Nanocomposites via Mechanochemical Method

2011 ◽  
Vol 478 ◽  
pp. 1-6
Author(s):  
Abbas Fahami ◽  
Reza Ebrahimi-Kahrizsangi ◽  
Bahman Nasiri-Tabrizi
Keyword(s):  
Electron Microscopy ◽  
Phase Evolution ◽  
Xrd Analysis ◽  
Dielectric Materials ◽  
Weight Percent ◽  
Structural Features ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Increasing Temperature

The mechanical activation was employed to study the phase evolution of the Mg–TiO2–CaHPO4–CaO nanocrystalline system. The powders mixture with certain weight percent was grinded. Thermal annealing process at 650°C, 900°C and 1100°C temperatures resulted in generation of different compounds like MgTiO3/MgO/Hydroxyapatite (HAp) and MgTiO3/MgO/β-TCP and MgTiO3/Mg2TiO4/MgO/β-TCP, respectively. The compounds were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDX). The consequences of XRD analysis revealed that by increasing temperature, some composites with different morphological and structural features were detected. Beside, due to decomposing of HAp around 800°C, HAp converted to whitlockite (β-TCP) with growth of temperature. According to SEM and TEM observations, it was found that the synthesized powder contained large agglomerates which significant content of finer particles and agglomerates with spherical morphology. Because magnesium titanates based dielectric materials are useful for electrical applications, the electrical property of HAp has been proved, and the incorporation of these materials could result in new nanocrystalline dielectric materials.

Structural, morphological, and magnetic study of nanocrystalline cobalt-copper powders synthesized by the polyol process

1995 ◽  
Vol 10 (6) ◽  
pp. 1546-1554 ◽  
Author(s):  
G.M. Chow ◽  
L.K. Kurihara ◽  
K.M. Kemner ◽  
P.E. Schoen ◽  
W.T. Elam ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Copper Powders ◽  
Face Centered ◽  
Increasing Temperature ◽  
X Ray Absorption

Nanocrystalline CoxCu100−x (4 ⋚ x ⋚ 49 at. %) powders were prepared by the reduction of metal acetates in a polyol. The structure of powders was characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), extended x-ray absorption fine structure (EXAFS) spectroscopy, solid-state nuclear magnetic resonance (NMR) spectroscopy, and vibrating sample magnetometry (VSM). As-synthesized powders were composites consisting of nanoscale crystallites of face-centered cubic (fcc) Cu and metastable face-centered cubic (fcc) Co. Complementary results of XRD, HRTEM, EXAFS, NMR, and VSM confirmed that there was no metastable alloying between Co and Cu. The NMR data also revealed that there was some hexagonal-closed-packed (hcp) Co in the samples. The powders were agglomerated, and consisted of aggregates of nanoscale crystallites of Co and Cu. Upon annealing, the powders with low Co contents showed an increase in both saturation magnetization and coercivity with increasing temperature. The results suggested that during preparation the nucleation of Cu occurred first, and the Cu crystallites served as nuclei for the formation of Co.

scholarly journals Synthesis, Characterization, and Photocatalytic Performance of Mesoporous α-Mn2O3 Microspheres Prepared via a Precipitation Route

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Manoj Pudukudy ◽  
Zahira Yaakob
Keyword(s):  
Electron Microscopy ◽  
Uv Light ◽  
Thermal Transformation ◽  
Xrd Analysis ◽  
Structural Deformation ◽  
Blue Dye ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
X Ray ◽  
Transmission Electron

α-Mn2O3 microspheres with high phase purity, crystallinity, and surface area were synthesized by the thermal decomposition of precipitated MnCO3 microspheres without the use of any structure directing agents and tedious reaction conditions. The prepared Mn2O3 microspheres were characterized by Fourier transform infrared (FTIR) spectroscopy, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) and photoluminescence (PL) studies. The complete thermal transformation of MnCO3 to Mn2O3 was clearly shown by the FTIR and XRD analysis. The electron microscopic images clearly confirmed the microsphere-like morphology of the products with some structural deformation for the calcined Mn2O3 sample. The mesoporous texture generated from the interaggregation of subnanoparticles in the microstructures is visibly evident from the TEM and BET studies. Moreover, the Mn2O3 microstructures showed a moderate photocatalytic activity for the degradation of methylene blue dye pollutant under UV light irradiation, using air as the potential oxidizing agent.

scholarly journals Investigation of the γ′ Precipitates Dissolution in a Ni-Based Superalloy During Stress-Free Short-Term Annealing at High Homologous Temperatures

2021 ◽  
Author(s):  
Łukasz Rakoczy ◽  
Małgorzata Grudzień-Rakoczy ◽  
Fabian Hanning ◽  
Grzegorz Cempura ◽  
Rafał Cygan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Lattice Parameters ◽  
X Ray Diffraction ◽  
Short Term ◽  
X Ray ◽  
Transmission Electron ◽  
Thermodynamic Simulations ◽  
The Matrix ◽  
Increasing Temperature

AbstractThe equiaxed Ni-based superalloy René 108 was subjected to short-term annealing at five temperatures between 900 °C and 1100 °C. The phase composition, phase lattice parameters, microstructure, stereological parameters, and chemical composition of γ′ precipitates were investigated by thermodynamic simulations, X-ray diffraction, scanning and transmission electron microscopy, and energy-dispersive X-ray spectroscopy. Analysis of the γ and γ′ lattice parameters using the Nelson-Riley extrapolation function showed that the misfit parameter for temperatures 900 °C to 1050 °C is positive (decreasing from 0.32 to 0.11 pct). At 1100 °C, the parameter becomes negative, δ = − 0.18 pct. During the short-term annealing, γ′ precipitates dissolution occurred progressing more rapidly with increasing temperatures. The surface fraction of γ′ precipitates decreased with increasing temperature from 0.52 to 0.34. The dissolution of γ′ precipitates did not only proceed through uninterrupted thinning of each individual precipitate, but also included more complex mechanisms, including splitting. Based on transmission electron microscopy, it was shown that after γ′ precipitates dissolution, the matrix close to the γ/γ′ interface is strongly enriched in Co and Cr and depleted in Al.

scholarly journals Hydrothermal Synthesis of MnWO4@GO Composite as Non-Precious Electrocatalyst for Urea Oxidation

Nanomaterials ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 85
Author(s):  
Patnamsetty Chidanandha Nagajyothi ◽  
Kisoo Yoo ◽  
Rajavaram Ramaraghavulu ◽  
Jaesool Shim
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Synthesis ◽  
Photoelectron Spectroscopy ◽  
Xrd Analysis ◽  
Morphological Characterization ◽  
Energy Storage And Conversion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Density Values

In this study, manganese tungstate (MW) and MW/graphene oxide (GO) composites were prepared by a facile hydrothermal synthesis at pH values of 7 and 12. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy were used for the structural, compositional, and morphological characterization of the nanoparticles (NPs). The XRD analysis revealed that the formation of monoclinic MnWO4 did not have impurities. The SEM and TEM analyses showed that the synthesized NPs were rod-shaped and well-distributed on the GO. The as-synthesized samples can be used as electrocatalysts for the urea oxidation reaction (UOR). The MW@GO-12 electrocatalyst exhibited higher current density values compared to other electrocatalysts. This study provides a new platform for synthesizing inexpensive nanocomposites as promising electrocatalysts for energy storage and conversion applications.

Enhancement of durability of NIR emission of Ag2S@ZnS QDs in water

2017 ◽  
Vol 31 (32) ◽  
pp. 1750297 ◽  
Author(s):  
M. Karimipour ◽  
M. Bagheri ◽  
M. Molaei
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Xrd Analysis ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Nir Emission ◽  
Core Shell Structure ◽  
Phase Transmission

Stability of Ag2S@ZnS QDs in water is a crucial concern for their application in biology. In this work, both physical sustainability and emission stability of Ag2S QDs were enhanced using parameter optimization of a pulsed microwave irradiation (MI) method up to 105 days after their preparation. UV–Vis and photoluminescence spectroscopies depicted an absorption and emission about 817 nm and 878 nm, respectively. X-ray diffraction (XRD) analysis showed a growth of Ag2S acanthite phase. Transmission Electron Microscopy (TEM) images revealed a clear formation of Ag2S@ZnS core–shell structure.

Synthesis and Characterization of Nano Hydroxylapatite by Reaction Precipitation in Impinging Streams

2010 ◽  
Vol 160-162 ◽  
pp. 1301-1308 ◽  
Author(s):  
Jun Yuan ◽  
Yuan Wu ◽  
Qi Xin Zheng ◽  
Xiao Lin Xie
Keyword(s):  
Electron Microscopy ◽  
Xrd Analysis ◽  
Synthesis And Characterization ◽  
Preparation Process ◽  
X Ray Diffraction ◽  
Excellent Performance ◽  
X Ray ◽  
Operation Conditions ◽  
Transmission Electron

Hydroxylapatite(HAP) nano-whiskers are prepared by reaction-precipitation in the submerged circulative impinging stream reactor(SCISR), with (NH4)2HPO4 and Ca(NO3)2 as the reagents; and the products are characterized by X-ray diffraction (XRD) analysis, Fourier transform infrared (FTIR) spectroscopy, Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). The results TEM measured indicate that the product prepared under typical operation conditions is average-sized 15nm and 50-70nm long. Multiply repeated experiments illustrates that, because of the excellent performance of the reactor, the preparation process can be easily controlled to yield nano rod/whisker hydroxylapatite with very narrow size distribution.

scholarly journals Investigation of Lithiated Carbons by Transmission Electron Microscopy and X-Ray Diffraction Analysis

1998 ◽  
Vol 548 ◽  
Author(s):  
T. D. Tran ◽  
X. Y. Song ◽  
K. Kinoshita
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Carbon Black ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Lattice Image ◽  
X Ray ◽  
Storage Mechanism ◽  
Transmission Electron ◽  
Diffraction Patterns

ABSTRACTThe microstructures of lithiated synthetic graphite and carbon black were studied by high- resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) analysis. Information about the crystal structure of carbon containing various Li compositions can provide useful insights to our understanding of the Li storage mechanism in carbonaceous materials. Samples with compositions of Li0.93C6or Li0.45C6 were found to contain both stage-one and stage-two compounds. These observations are consistent with XRD data. The changes in sample microstructure as the results of lithiation and exposure to electron irradiation were observed by TEM and recorded over several minutes in the microscope environment. Selected area electron diffraction patterns indicated that the lithiated samples quickly changed composition to LiC 24, which appeared to dominate during the brief analysis period. The layer planes in the lattice image of a disordered carbon black after Li insertion are poorly defined, and changes in the microstructure of these lithiated carbons was not readily apparent. Observations on these lithium intercalation compounds as well as the limitation of the experimental procedure will be presented.

Preparation of Chrysotile Nanotubes under Hydrothermal Condition

2011 ◽  
Vol 284-286 ◽  
pp. 688-691 ◽  
Author(s):  
Yang Feng Huang ◽  
Ye Bin Cai ◽  
Hao Liu
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Condition ◽  
Xrd Analysis ◽  
Outer Diameter ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure And Morphology ◽  
Transmission Electron ◽  
Inner Diameter ◽  
Temperature And Pressure

In a neutral environment, Chrysotile nanotubes have been synthesized by hydrothermal method, with MgO and SiO2powder as the starting materials. X-Ray Diffraction(XRD), Scanning Electron Microscopy(SEM), Transmission Electron Microscopy(TEM) are used to characterize the crystal structure and morphology of the as-prepared samples. We found that the diameter of Chrysotile is uniform. Their outer diameter is about 30~50 nm and the inner diameter is about 6~8 nm. The length of them is a few hundred nanometers. The XRD analysis indicates that the as-prepared Chrysotile is a Rhombohedral structures. The results of HRTEM and SAED showed that the {006} planes of serpentine roll up along the [600] direction to form the tubular structure. In addition, the curves of temperature and pressure with time showed that the water might participate in the reaction.

scholarly journals Study of α-Fe2O3@ ZnO nanoleaves: Morphological and optical study

2020 ◽  
Vol 2 (1) ◽  
pp. 118-124
Author(s):  
Parastoo Khalili ◽  
◽  
Majid Farahmandjou ◽  
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Weight Percent ◽  
Optical Study ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Transmission Electron ◽  
Stretching Vibrations ◽  
Scanning Electron

In this paper, α-Fe2O4@ZnO nanoparticles (NPs) were synthesized by coprecipitation method in the presence of PVP and EG surfactants. The samples were charactrized by x-ray fluorescence (XRF), x-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), and fourier transform infrared spectroscopy (FTIR). The XRD results exhibited rhombohedral α-Fe2O3 and wurtzite structure of ZnO. The SEM images showed that the NPs changed from rod-shape to nanoleaves particles after heat treatment. The TEM studies displayed the formation of Fe2O3@ZnO core-shell of as-synthesized NPs. The stretching vibrations peaks in FTIR in the wavenumber of 532 cm-1 and 473 cm-1 ascribed to the Fe and Zn groups. The XRF data indicated decreasing of the Fe weight percent from 22 %Wt. to 25 %Wt., after heat treatment.

Phase Evolution During Ball Milling of Al In NH3 and Subsequent Annealing

1997 ◽  
Vol 481 ◽  
Author(s):  
J. I Nikolov ◽  
J. S. Williams ◽  
D. J. Llewellyn ◽  
A. Calka
Keyword(s):  
Electron Microscopy ◽  
Ball Milling ◽  
Hollow Spheres ◽  
Analytical Techniques ◽  
Phase Evolution ◽  
X Ray Diffraction ◽  
Combustion Analysis ◽  
X Ray ◽  
Transmission Electron ◽  
O Phase

ABSTRACTPhase evolution during ball milling of Al in both N2 and NH3 gas has been compared and the annealing behaviour studied in some detail. X-ray diffraction, differential thermal analysis, combustion analysis and scanning and transmission electron microscopy have been used as analytical techniques. Results have shown that a nitride is not formed in N2 but that Al forms into many small, hollow spheres during milling. In contrast, milling in NH3 results in an amorphous AlxNy(O) phase which transforms into crystalline AIN and A12O3 on annealing to 1000°C.

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