Formation of (Fe,Cr) carbides and dislocation structures in low-chromium steel studiedin situusing synchrotron radiation

2012 ◽  
Vol 46 (1) ◽  
pp. 181-192 ◽  
Author(s):  
E. Gözde Dere ◽  
Hemant Sharma ◽  
Richard M. Huizenga ◽  
Giusseppe Portale ◽  
Wim Bras ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Size Distribution ◽  
Room Temperature ◽  
Rapid Heating ◽  
Chromium Steel ◽  
Dispersion Parameter ◽  
Precipitate Size ◽  
Two Dimensional ◽  
X Ray ◽  
Transmission Electron

The evolution of the size distribution of (Fe,Cr) carbides and the dislocation structure in low-chromium steel is studied during quenching and rapid heating byin situsmall-angle X-ray scattering (SAXS). The two-dimensional SAXS patterns consist of streaks on top of an isotropic SAXS signal. The evolution of the size distribution of the (Fe,Cr) carbides during heat treatment is determined from the isotropic component of the SAXS patterns. The isotropic part of the SAXS patterns shows that, after austenitization and quenching to room temperature, the average precipitate radius is 4.74 nm and the dispersion parameter for the lognormal size distribution is 0.33. Subsequent rapid heating to 823 K results in an average precipitate size of 5.25 nm and a dispersion parameter of 0.26. Bright-field transmission electron microscopy and high-resolution transmission electron microscopy reveal the nearly spherical morphology of the precipitates. The microstructural evolution underlying the increase in the average precipitate size and the decrease in the dispersion parameter after heating to and annealing at 823 K is probably that at room temperature two types of precipitates are present,i.e.(Fe,Cr)23C6and (Fe,Cr)7C3precipitates according to thermodynamic calculations, and at 823 K only (Fe,Cr)7C3precipitates are present. Additional measurements have been carried out on a single crystal of ferrite containing (Fe,Cr) carbides by combining three-dimensional X-ray diffraction (3DXRD) and SAXS during rotation of the specimen at room temperature, in order to investigate the origin of the streaks at low angles in the SAXS pattern. From simulations based on the theory of SAXS from dislocations, it is shown that the measured streaks, including the spottiness, in the two-dimensional SAXS patterns correspond to a dislocation structure of symmetric low-angle tilt boundaries, which in turn corresponds to the crystallographic orientation gradient in the single crystal of ferrite as measured by 3DXRD microscopy.

SYNTHESIS AND CHARACTERIZATION OF COBALT FERRITES MAGNETIC NANOPARTICLES IN ALKANETHIOL SOLUTION

2004 ◽  
Vol 03 (04n05) ◽  
pp. 639-648
Author(s):  
W. T. KERK ◽  
J. M. LI ◽  
W. S. CHIN ◽  
A. C. H. HUAN
Keyword(s):  
Electron Microscopy ◽  
Magnetic Nanoparticles ◽  
Size Distribution ◽  
Room Temperature ◽  
Cobalt Ferrite ◽  
Homogeneous Solution ◽  
X Ray ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Cobalt Ferrites

Magnetic nanoparticles of cobalt ferrite have been synthesized in a homogeneous solution containing dodecanethiol at room temperature. The alkanethiol molecules have provided a mean to control the particle size distribution. The uniformed size distribution, crystallinity and morphology of these nanoparticles are characterized with X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). The stoichiometry of the cobalt ferrite is confirmed by both elemental analysis and Energy Dispersive X-ray (EDX). Fabrication of assembled arrays of these nanoparticles on Si (100) have been achieved by slow evaporation of the solution and studied by Atomic Force Microscopy (AFM). Magnetic properties of the nanoparticles are determined by Vibrating Sample Magnetometer (VSM) and show a magnetization (Ms) of 75.3 emu/g and a coercivity (Hc) of 1500 Oe at room temperature.

Synthesis and Photoluminescence Properties of Novel SnO2 Zigzag Nanoribbons

2010 ◽  
Vol 97-101 ◽  
pp. 4213-4216
Author(s):  
Jian Xiong Liu ◽  
Zheng Yu Wu ◽  
Guo Wen Meng ◽  
Zhao Lin Zhan
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Ceramic Boat

Novel single-crystalline SnO2 zigzag nanoribbons have been successfully synthesized by chemical vapour deposition. Sn powder in a ceramic boat covered with Si plates was heated at 1100°C in a flowing argon atmosphere to get deposits on a Si wafers. The main part of deposits is SnO2 zigzag nanoribbons. They were characterized by means of X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and selected-area electron diffraction (SAED). SEM observations reveal that the SnO2 zigzag nanoribbons are almost uniform, with lengths near to several hundred micrometers and have a good periodically tuned microstructure as the same zigzag angle and growth directions. Possible growth mechanism of these zigzag nanoribbons was discussed. A room temperature PL spectrum of the zigzag nanoribbons shows three peaks at 373nm, 421nm and 477nm.The novel zigzag microstructures will provide a new candidate for potential application.

A Facile Fynthesis of ZnS Nanostructures via Liquid-Solid Reactions

2014 ◽  
Vol 979 ◽  
pp. 184-187
Author(s):  
Weerachon Phoohinkong ◽  
Thitinat Sukonket ◽  
Udomsak Kitthawee
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Inorganic Salts ◽  
Chloride Salt ◽  
X Ray ◽  
Commercial Grade ◽  
Transmission Electron ◽  
Salt Addition ◽  
20 Nm ◽  
Scanning Electron

Zinc sulfide (ZnS) nanostructures are important materials for many technologies such as sensors, infrared windows, transistors, LED displays, and solar cells. However, many methods of synthesizing ZnS nanostructures are complex and require expensive equipment. In this study, a liquid-solid chemical reaction without surfactant was used to synthesize ZnS at room temperature. In addition, commercial grade zinc oxide (ZnO) particles were used as a precursor. The effect of the addition of acids and inorganic salts were investigated. The products were characterized by field emission scanning electron microscopy (FESEM) coupled with energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM). The results show that the nanoparticles of ZnS were obtained in hydrochloric acid and acetic acid addition. The diameters were in the range of 10 to 20 nm and 50 to 100 nm, respectively. In the case of a sodium chloride salt addition, a ZnS structure was obtained with a particle size of approximately 5 nm and a flake-like morphology.

New method for the production of bulk amorphous materials of Nd–Fe–B alloys

2005 ◽  
Vol 20 (3) ◽  
pp. 563-566 ◽  
Author(s):  
Tetsuji Saito ◽  
Hiroyuku Takeishi ◽  
Noboru Nakayama
Keyword(s):  
Electron Microscopy ◽  
Amorphous Materials ◽  
Room Temperature ◽  
Amorphous Structure ◽  
X Ray Diffraction ◽  
Bulk Materials ◽  
X Ray ◽  
Transmission Electron ◽  
Melt Spun ◽  
Melt Spun Ribbons

We report a new compression shearing method for the production of bulk amorphous materials. In this study, amorphous Nd–Fe–B melt-spun ribbons were successfully consolidated into bulk form at room temperature by the compression shearing method. X-ray diffraction and transmission electron microscopy studies revealed that the amorphous structure was well maintained in the bulk materials. The resultant bulk materials exhibited the same magnetic properties as the original amorphous Nd–Fe–B materials.

Room Temperature Self-Annealing of Electroplated and Sputtered Copper Films

1999 ◽  
Vol 562 ◽  
Author(s):  
Michelle Chen ◽  
Suraj Rengarajan ◽  
Peter Hey ◽  
Yezdi Dordi ◽  
Hong Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Copper Film ◽  
Copper Films ◽  
Organic Additives ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Electroplated Copper ◽  
Effect Of Copper

ABSTRACTSelf-annealing properties of electroplated and sputtered copper films at room temperature were investigated in this study, in particular, the effect of copper film thickness, electrolyte systems used, as well as their level of organic additives for electroplating. Real-time grain growth was observed by transmission electron microscopy. Sheet resistance and X-ray diffraction measurements further confirmed the recrystallization of the electroplated copper film with time. The recrystallization of electroplated films was then compared with that of sputtered copper films.

scholarly journals Hyperfine interaction and some thermomagnetic properties of amorphous and partially crystallized Fe70−xMxMo5Cr4Nb6B15 (M = Co or Ni, x = 0 or 10) alloys

Nukleonika ◽  
2015 ◽  
Vol 60 (1) ◽  
pp. 121-126
Author(s):  
Jakub Rzącki ◽  
Jan Świerczek ◽  
Mariusz Hasiak ◽  
Jacek Olszewski ◽  
Józef Zbroszczyk ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Hyperfine Interaction ◽  
Magnetic Structure ◽  
Curie Point ◽  
Room Temperature ◽  
Ferromagnetic Phase ◽  
X Ray ◽  
Transmission Electron ◽  
Thermomagnetic Properties

Abstract As revealed by Mössbauer spectroscopy, replacement of 10 at.% of iron in the amorphous Fe70Mo5Cr4Nb6B15 alloy by cobalt or nickel has no effect on the magnetic structure in the vicinity of room temperature, although the Curie point moves from 190 K towards ambient one. In the early stages of crystallization, the paramagnetic crystalline Cr12Fe36Mo10 phase appears before α-Fe or α-FeCo are formed, as is confirmed by X-ray diffractometry and transmission electron microscopy. Creation of the crystalline Cr12Fe36Mo10 phase is accompanied by the amorphous ferromagnetic phase formation at the expense of amorphous paramagnetic one.

scholarly journals A Novel X-Ray Radiation Sensor Based on Networked SnO2 Nanowires

2019 ◽  
Vol 9 (22) ◽  
pp. 4878 ◽  
Author(s):  
Jae-Hun Kim ◽  
Ali Mirzaei ◽  
Hyoun Woo Kim ◽  
Hong Joo Kim ◽  
Phan Quoc Vuong ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Low Cost ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Radiation Sensor ◽  
Sno2 Nanowires ◽  
Radiation Sensors

X-Ray radiation sensors that work at room temperature are in demand. In this study, a novel, low-cost real-time X-ray radiation sensor based on SnO2 nanowires (NWs) was designed and tested. Networked SnO2 NWs were produced via the vapor–liquid–solid technique. X-ray diffraction (XRD), transmission electron microscopy (TEM) and field emission scanning electron microscopy (SEM) analyses were used to explore the crystallinity and morphology of synthesized SnO2 NWs. The fabricated sensor was exposed to X-rays (80 kV, 0.0–2.00 mA) and the leakage current variations were recorded at room temperature. The SnO2 NWs sensor showed a high and relatively linear response with respect to the X-ray intensity. The X-ray sensing results show the potential of networked SnO2 NWs as novel X-ray sensors.

scholarly journals Designing Magnetic Layered Double Hydroxides and Two-Dimensional Magnetic Nano-Nets of Cobalt Ferrite through a Novel Approach

2018 ◽  
Vol 8 (11) ◽  
pp. 2099 ◽  
Author(s):  
Osama Saber ◽  
Abdullah Aljaafari ◽  
Sarah Asiri ◽  
Khalid Batoo
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Layered Double Hydroxides ◽  
Cobalt Ferrite ◽  
High Coercivity ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Double Hydroxides

The present study has a dual aim of supporting magnetic nanoparticles over the nanolayers of LDHs and designing two-dimensional magnetic nano-nets of cobalt ferrite. In this trend, nanoparticles of CoFe2O4 were prepared and supported by Co-Fe LDH through urea hydrolysis. The nanolayered structures of Co-Fe LDH were confirmed by X-ray diffraction, energy-dispersive X-ray spectrometry, FT-IR spectra, thermal analyses, and transmission electron microscopy. In addition, they indicated that 13.2% CoFe2O4 were supported over Co-Fe LDH. Transformation of the nanolayered structures of Co-Fe LDH to nano-nets was achieved by the catalytic effect of the supported CoFe2O4 nanoparticles through solvent thermal technique. X-ray diffraction patterns and transmission electron microscopy images confirmed the transformation of the supported Co-Fe LDH to nano-nets of cobalt ferrite. In order to indicate the effect of the LDH for designing the nano-nets, nanoparticles of cobalt ferrite were prepared by the same technique without LDH. The magnetic behavior of the nano-nets and the supported Co-Fe LDH were measured and compared with the nanoparticles through vibrating sample magnetometer technique. The magnetic parameters indicated that the prepared nano-nets have ferromagnetic behavior and high coercivity. However, the prepared nanoparticles revealed a superparamagnetic state and low coercivity. The experimental results concluded that the incorporation of nanoparticles with nanowires into nano-net structures has been found to be an efficient way to improve their magnetic properties and prevent their agglomerations. Finally, layered double hydroxides are an important source for constructing magnetic nanolayered structures and nano-nets.

Effect of Au on the Performance of Porous Silicon/V2O5 Nanorods Heterojunctions to NO2 Gas

NANO ◽  
2016 ◽  
Vol 11 (07) ◽  
pp. 1650079 ◽  
Author(s):  
Wenjun Yan ◽  
Ming Hu ◽  
Jiran Liang ◽  
Dengfeng Wang ◽  
Yulong Wei ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Porous Silicon ◽  
Room Temperature ◽  
Au Nanoparticles ◽  
Analytical Techniques ◽  
Heating Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

A novel composite of Au-functionalized porous silicon (PS)/V2O5 nanorods (PS/V2O5:Au) was prepared to detect NO2 gas. PS/V2O5 nanorods were synthesized by a heating process of pure vanadium film on PS, and then the obtained PS/V2O5 nanorods were functionalized with dispersed Au nanoparticles. Various analytical techniques, such as field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), have been employed to investigate the properties of PS/V2O5:Au. Herein, the PS/V2O5:Au sample exhibited improved NO2-sensing performances in response, stability and selectivity at room temperature (25[Formula: see text]C), compared with the pure PS/V2O5 nanorods. These phenomena were closely related to not only the dispersed Au nanoparticles acting as a catalyst but also the p-n heterojunctions between PS and V2O5 nanorods. Whereas, more Au nanoparticles suppressed the improvement of response to NO2 gas.

Synthesis of Silicon Carbide Nanoparticles from Carbon Nanotubes

2012 ◽  
Vol 602-604 ◽  
pp. 183-186 ◽  
Author(s):  
Jing Liu ◽  
Rong Wu ◽  
Jin Li ◽  
Yan Fei Sun ◽  
Ji Kang Jian
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Scanning Electron Microscopy ◽  
Silicon Carbide ◽  
Room Temperature ◽  
Sic Nanoparticles ◽  
X Ray ◽  
Transmission Electron ◽  
Cubic Silicon Carbide ◽  
Scanning Electron

In this paper, we report the synthesis of cubic silicon carbide (3C-SiC) nanoparticles by direction reaction of silicon powders and carbon nanotubes. The as-prepared SiC nanoparticles were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy and Raman scattering at room temperature. The possible growth mechanism is proposed.

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