Thermal and Structural Characterization of Nanocomposite Iron Nitride - Alumina and Iron Nitride - Silica Particles

2001 ◽  
Vol 703 ◽  
Author(s):  
Ann M. Viano ◽  
Sanjay R. Mishra
Keyword(s):  
Particle Size ◽  
Milling Time ◽  
Iron Nitride ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Peak ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
The One

ABSTRACTNanocomposite iron nitride based powders are known to have enhanced magnetic and other physical properties. To further explore their potential for application in various fields, we have performed a systematic study of the iron nitride - alumina and iron nitride - silica systems. Iron nitride powder of composition FexN (2 < x < 4), containing both Fe3N and Fe4N phases, was mechanically milled with Al2O3 or SiO2 powder for 4, 8, 16, 32, and 64 hours at the following compositions; (FexN)0.2(Al2O3)0.8, (FexN)0.6(Al2O3)0.4, (FexN)0.2(SiO2)0.8, and (FexN)0.6(SiO2)0.4. Differential thermal analysis and X-ray diffraction were performed to investigate thermal and structural transitions as a function of milling time. As the milling time is increased, the thermal peak corresponding to Fe4N is diminished, while the one corresponding to Fe3N is enhanced. These transitions are correlated with X-ray diffraction patterns. All XRD peaks broaden as a function of milling time, corresponding to smaller particle size. Transmission electron microscopy also reveals a decrease in particle size as the milling time in increased.

Effect of Process on the Dielectric Properties of BaTiO3-Based X9R Ceramics

2014 ◽  
Vol 906 ◽  
pp. 18-24 ◽  
Author(s):  
Bao Lin Zhang ◽  
Bin Bin Zhang ◽  
Ning Ning Wang ◽  
Jing Ming Fei
Keyword(s):  
Particle Size ◽  
Dielectric Properties ◽  
Milling Time ◽  
Sintering Temperature ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
Sintered Ceramic ◽  
X Ray ◽  
Particle Size Analyzer

The effect of milling time and sintering process on the dielectric properties of BaTiO3-based X9R ceramics was investigated. The characterization of the raw powders and the sintered ceramic was carried out by X-ray diffraction and scanning electron microscopy. The particle size distribution of the mixed powders was examined by Laser Particle Size Analyzer. The results shown that with the milling time extended, the Cruie Peak was depressed, or even disappeared. Moreover, with the rise of sintering temperature, the dielectric constant of the ceramics increased and the dielectric loss decreased gradually. Eventually, by milling for 11h and sintering at 1090°Cfor 2h, good dielectric properties were obtained, which were ε25°C≥ 2526, εr/εr25°C≤± 12% (–55~200°C), tanδ≤1.12% (25°C).

DSC-TGA Hydrogen Evaluation during Mechanical Milling of AlFe Intermetallic

2013 ◽  
Vol 755 ◽  
pp. 105-110 ◽  
Author(s):  
E. García de León M. ◽  
O. Téllez-Vázquez ◽  
C. Patiño-Carachure ◽  
G. Rosas
Keyword(s):  
Mechanical Milling ◽  
Milling Time ◽  
Hydrogen Generation ◽  
Pure Aluminum ◽  
High Energy ◽  
Milling Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Diffraction Patterns

Fe40Al60 (at%) intermetallic alloy composition was obtained by conventional casting methods and subsequently subjected to high-energy mechanical milling under different conditions of humidity. All samples were characterized by X-ray diffraction patterns (XRD), transmission electron microcopy (TEM) and DSC-TGA thermogravimetric experiments. After the milling process, the amount of hydrogen generated was determined using thermogravimetric analysis and chemical reactions (stoichiometry). All techniques confirm the formation of bayerite phase which is attributed to the hydrogen embrittlement reaction between the intermetallic material and water to release hydrogen. It was observed that the hydrogen generation is increased as the ball milling time is increased. The quantity of hydrogen evaluated is similar to that obtained in previous reported experiments with pure aluminum and some of its alloys.

Structural Characterization of Nano-Crystalline Mg2Si Prepared by Ball Milling

2010 ◽  
Vol 74 ◽  
pp. 48-53 ◽  
Author(s):  
Maria Ioannou ◽  
Euripides Hatzikraniotis ◽  
Christos B. Lioutas ◽  
Konstantinos M. Paraskevopoulos ◽  
Theodora Kyratsi
Keyword(s):  
Ball Milling ◽  
Milling Time ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nano Crystalline ◽  
Transmission Electron ◽  
Size Evolution ◽  
Line Analysis

In this work, nano-crystalline Mg2Si powder was prepared by ball milling and structural studies vs ball milling time are presented. The identification of the phases of the materials and the evaluation of their purity were performed using Powder X-ray diffraction (PXRD). Crystallite size evolution during ball milling was followed by PXRD and single line analysis, based on Scherrer equation. Transmission Electron microscopy (TEM) observations and IR Reflectivity measurements were used for the investigation of nano-features and confirmation of the PXRD results.

scholarly journals Structural, Optical, and Photocatalytic Properties of ZnSe Nanoparticles Influenced by the Milling Time

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1125
Author(s):  
Bui Thi Thu Hien ◽  
Vu Thanh Mai ◽  
Pham Thi Thuy ◽  
Vu Xuan Hoa ◽  
Tran Thi Kim Chi
Keyword(s):  
Raman Spectra ◽  
Milling Time ◽  
Blue Emission ◽  
Near Band Edge ◽  
X Ray Diffraction ◽  
Znse Nanoparticles ◽  
X Ray ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
Average Size

ZnSe nanoparticles (NPs) were prepared by combining both hydrothermal and mechanical milling methods. Transmission electron microscopy images show that fabricated ZnSe NPs with a sphere-like shape have an average size (d) in the range of 20–100 nm, affected by changing the milling time from 10 to 60 min. All the samples crystalize in zincblende-type structure without impurities, as confirmed by analyzing X-ray diffraction patterns, Raman spectra, and energy-dispersive X-ray spectroscopy. Carefully checking Raman spectra, we have observed the broadening and redshift of vibration modes as decreasing NP size, which are ascribed to extra appearance of disorder and defects. The photoluminescence study has found a blue emission at 462 nm attributed to the excitonic near-band edge and a broad defect-related emission around 520–555 nm. Increasing milling time leads to the decrease in the exciton-emission intensity, while the defect-related emissions increase gradually. Interestingly, as decreasing d, we have observed an improved photodegradation of Rhodamine B under UV irradiation, proving application potentials of ZnSe NPs in photocatalytic activity.

Synthesis and Characterization of CoMn2O4 Nanopowders by a Reverse Micelle Processing

2016 ◽  
Vol 868 ◽  
pp. 105-110
Author(s):  
Dong Sik Bae
Keyword(s):  
Reverse Micelle ◽  
Molar Ratio ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Xrd Diffraction ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
Average Size

CoMn2O4 nanoparticles were synthesized by reverse micelle processing from the mixed precursor (consisting of Co (NO3)2 ·6H2O and MnCl2·4H2O). The CoMn2O4 was prepared by mixing the aqueous solution at a molar ratio of Co : Mn = 1 : 2. The synthesized powders were calcined at 600°C for 2h. The average size and distribution of synthesized powders were in the range of 10-20nm and narrow, respectively. The average size of the synthesized powders increased with increasing water to surfactant molar ratio. The XRD diffraction patterns show that the phase of CoMn2O4 was spinel (JCPDS no.77-0471). The synthesized and calcined powders were characterized by thermogravimetry-differential scanning calorimeter (TG-DSC), X-ray diffraction analysis (XRD) and transmission electron microscopy (TEM). The magnetic property of the powder was measured by Vibrating Sample Magneto-meter (VSM) at 298K. The effect of synthesis parameter, such as the molar ratio of water to surfactant, is discussed.

TEM and XRD Investigation of MnO2 Microstructure and its Influence on ESR of Ta Capacitors

2006 ◽  
Vol 514-516 ◽  
pp. 269-273
Author(s):  
Décio Dias ◽  
Rui Monteiro ◽  
Patrícia Almeida Carvalho ◽  
Alberto C. Ferro ◽  
Werner Lohwasser
Keyword(s):  
Complex Structure ◽  
Semiconductor Layer ◽  
Equivalent Series Resistance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Equivalent Circuit Parameters ◽  
Diffraction Peaks ◽  
Diffraction Patterns

The development of solid electrolytic tantalum capacitors with MnO2 as counter electrode has been carried out in order to decrease the equivalent series resistance (ESR). Capacitor samples produced under different pyrolysis conditions have been characterized in terms of equivalent circuit parameters. The Ta/Ta2O5/MnO2 system has also been characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). X-ray powder diffraction patterns obtained were inconclusive due to the MnO2 complex structure and to the presence of highly intense tantalum peaks that shadow interesting MnO2 diffraction peaks. Electron diffraction TEM results enabled the characterization of the microstructure and furthermore revealed the complex crystalline structure that affects the electrical properties of the semiconductor layer. A relation between the calculated circuit parameters and microstructure of MnO2 is discussed.

Electron microscope and X-ray diffraction studies of filamentous illitic clay from sandstones of the Magnus Field

Clay Minerals ◽  
1982 ◽  
Vol 17 (1) ◽  
pp. 23-40 ◽  
Author(s):  
W. J. McHardy ◽  
M. J. Wilson ◽  
M. Tait
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Pore Space ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Critical Point Drying ◽  
Diffraction Patterns ◽  
The One ◽  
The Individual

AbstractScanning electron microscopy revealed that the organization of the interstitial micaceous mineral in the title sandstones depended on the manner of drying of the specimen. After air- and freeze-drying, the lath-like mineral tended to occur as mats densely packed against the pore walls, whereas after critical-point drying an open tangled web of very long, thin ribbons virtually filling the pore space was observed (this arrangement is the one most likely to occur in situ). The ends of these filamentous ribbons often appear to be bedded in authigenic quartz overgrowths on sand grains, thus anchoring them firmly in the pores. From transmission electron microscope observations, the individual laths were frequently only 2–3 nm thick and, from electron diffraction patterns, elongated along the a-axis: the stacking modification is 1M. X-ray diffraction patterns are those that would be expected from a fully-ordered interstratified mica-smectite containing ∼20% smectite layers. It is difficult to reconcile this with the thickness as observed under the transmission electron microscope, but a possible explanation is that the ‘smectite’ interlayers in reality represent spaces between individual crystals which formed when they sedimented into an oriented aggregate.

Preparation and characterization of poly(2-hydroxyethyl methacrylate)/ Na-montmorillonite intercalated nanocomposites

2013 ◽  
Vol 33 (1) ◽  
pp. 27-32 ◽  
Author(s):  
Zafer Koç ◽  
Meltem Çelik ◽  
Müşerref Önal ◽  
Yüksel Sarıkaya ◽  
Yesim Mogulkoc
Keyword(s):  
Interlayer Spacing ◽  
Hydroxyethyl Methacrylate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Monomer Content ◽  
Diffraction Patterns ◽  
Thermal Stability Of

Abstract A series of intercalated nanocomposites were prepared via in situ polymerization of 2-hydroxyethyl methacrylate (HEMA) between the interlayer spacing of hydrous Na-montmorillonite (Na-MMT) using benzoyl peroxide (Bz2O2) as a radical initiator. X-ray diffraction patterns showed the absence of any intercalation up to 61.7 mass% of HEMA, but anhydrous Na-MMT formed by the hydrophilic effect of HEMA. The interlayer spacing (d001) values of hydrous and anhydrous Na-MMT were calculated as 1.19 and 1.03 nm, respectively. At higher monomer contents, the increase in the value of d001 from 1.19 to 2.01 nm indicated intercalation of polymer in the interlayer spacing of Na-MMT. Besides, transmission electron microscopy results supported the formation of the intercalated nanocomposites. Thermogravimetric analysis showed that the thermal stability of the nanocomposites increased considerably by intercalation of pure poly-HEMA. Specific surface area and specific nanopore volume of the nanocomposites decreased with the increasing of the monomer content taken by the preparations. The decrease is due to the nonporous nature of the polymer matrix.

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.

Detonation Synthesis of Nano-Size Materials

1995 ◽  
Vol 418 ◽  
Author(s):  
J. Forbes ◽  
J. Davis ◽  
C. Wong
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Nucleation And Growth ◽  
Detonation Synthesis ◽  
X Ray Diffraction ◽  
Crystalline Materials ◽  
X Ray ◽  
Transmission Electron ◽  
Nano Size

AbstractThe detonation of explosives typically creates 100's of kbar pressures and 1000's K temperatures. These pressures and temperatures last for only a fraction of a microsecond as the products expand. Nucleation and growth of crystalline materials can occur under these conditions. Recovery of these materials is difficult but can occur in some circumstances. This paper describes the detonation synthesis facility, recovery of nano-size diamond, and plans to synthesize other nano-size materials by modifying the chemical composition of explosive compounds. The characterization of nano-size diamonds by transmission electron microscopy and electron diffraction, X-ray diffraction and Raman spectroscopy will also be reported.

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