Low-temperature instability of Ti2SnC: A combined transmission electron microscopy, differential scanning calorimetry, and x-ray diffraction investigations

2009 ◽  
Vol 24 (1) ◽  
pp. 39-49 ◽  
Author(s):  
J. Zhang ◽  
B. Liu ◽  
J.Y. Wang ◽  
Y.C. Zhou
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Low Temperature ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Temperature Instability ◽  
X Ray ◽  
Transmission Electron ◽  
Ceramic Microstructure

Transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and x-ray diffraction (XRD) investigations were conducted on the hot-pressed Ti2SnC bulk ceramic. Microstructure features of bulk Ti2SnC ceramic were characterized by using TEM, and a needle-shaped β-Sn precipitation was observed inside Ti2SnC grains with the orientation relationship: (0001) Ti2SnC // (200) Sn and Ti2SnC // [001] Sn. With the combination of DSC and XRD analyses, the precipitation of metallic Sn was demonstrated to be a thermal stress-induced process during the cooling procedure. The reheating temperature, even as low as 400 °C, could trigger the precipitation of Sn from Ti2SnC, which indicated the low-temperature instability of Ti2SnC. A substoichiometry Ti2SnxC formed after depletion of Sn from ternary Ti2SnC phase. Under electron beam irradiation, metallic Sn was observed diffusing back into Ti2SnxC. Furthermore, a new Ti7SnC6 phase with the lattice constants of a = 0.32 and c = 4.1 nm was identified and added in the Ti-Sn-C ternary system.

Crystallization of Amorphous Si In Al/Si Multilayers

1991 ◽  
Vol 230 ◽  
Author(s):  
Toyohiko J. Konno ◽  
Robert Sinclair
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Layered Structure ◽  
Heat Of Reaction ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
Amorphous Si

AbstractThe crystallization of amorphous Si in a Al/Si multilayer (with a modulation length of about 120Å) was investigated using transmission electron microscopy, differential scanning calorimetry and X-ray diffraction. Amorphous Si was found to crystallize at about 175 °C with the heat of reaction of 11±2(kJ/mol). Al grains grow prior to the nucleation of crystalline Si. The crystalline Si was found to nucleate within the grown Al layers. The incipient crystalline Si initially grows within the Al layer and then spreads through the amorphous Si and other Al layers. Because of extensive intermixing, the original layered structure is destroyed. The Al(111) texture is also enhanced.

Preparation and Property of Al87Ce3Ni8.5Mn1.5 Nanophase Amorphous Composites

2011 ◽  
Vol 412 ◽  
pp. 263-266
Author(s):  
Hong Wei Zhang ◽  
Li Li Zhang ◽  
Feng Rui Zhai ◽  
Jia Jin Tian ◽  
Can Bang Zhang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Single Phase ◽  
Volume Fraction ◽  
Material Structure ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
Different Temperatures

The higher mechanical strength of Al87Ce3Ni8.5Mn1.5 nanophase amorphous composites has been obtained with two methods. The first nanophase amorphous composites are directly produced by the single roller spin quenching technology. The method taken for the second nanophase amorphous composites is at first to obtain amorphous single-phase alloy, followed by annealed at different temperatures .The formative condition, the microstructure, the particle size, the volume fraction of α-Al phase and microhardness of nanophase amorphous composites etc have been investigated and compared by X-ray diffraction (XRD) and transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The microstructure of composites produced by the second method is higher than the former, the fabricated material structure of the system is more uniform and the process is easier to control.

Room Temperature Synthesis of Cu2O Nanospheres: Optical Properties and Thermal Behavior

2014 ◽  
Vol 21 (1) ◽  
pp. 108-119 ◽  
Author(s):  
Daniela Nunes ◽  
Lídia Santos ◽  
Paulo Duarte ◽  
Ana Pimentel ◽  
Joana V. Pinto ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Thermal Behavior ◽  
Room Temperature ◽  
Diffuse Reflectance Spectroscopy ◽  
Ion Beam ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron

AbstractThe present work reports a simple and easy wet chemistry synthesis of cuprous oxide (Cu2O) nanospheres at room temperature without surfactants and using different precursors. Structural characterization was carried out by X-ray diffraction, transmission electron microscopy, and scanning electron microscopy coupled with focused ion beam and energy-dispersive X-ray spectroscopy. The optical band gaps were determined from diffuse reflectance spectroscopy. The photoluminescence behavior of the as-synthesized nanospheres showed significant differences depending on the precursors used. The Cu2O nanospheres were constituted by aggregates of nanocrystals, in which an on/off emission behavior of each individual nanocrystal was identified during transmission electron microscopy observations. The thermal behavior of the Cu2O nanospheres was investigated with in situ X-ray diffraction and differential scanning calorimetry experiments. Remarkable structural differences were observed for the nanospheres annealed in air, which turned into hollow spherical structures surrounded by outsized nanocrystals.

Synthesis of VO2(A) Nanostructures by a Hydrothermal Method and their Transition to VO2(M)

2011 ◽  
Vol 295-297 ◽  
pp. 368-372 ◽  
Author(s):  
Ya Lan Zhong ◽  
Yi Fu Zhang ◽  
Xin Liu ◽  
Xing Hai Liu ◽  
Chi Huang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Phase Transition ◽  
Transmission Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Hydrothermal Method ◽  
Scanning Calorimetry ◽  
Facile Hydrothermal Method ◽  
X Ray ◽  
Transmission Electron ◽  
First Time

VO2(A) nanobelts have been synthesized using V2O5, H2O2, ethanol, H2O as the starting materials through a facile hydrothermal method. The as-obtained products were characterized by X-ray powder diffraction (XRD), X-ray photoelecton spectroscopy (XPS), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). Some parameters, such as, the reaction time, reaction temperature and the ratio of EtOH/H2O, have greatly influenced on the phases and morphologies of the final products. It was found that VO2(A) can be converted to VO2(M) at 700 °C for 2 h for the first time. Furthermore, the phase transition properties of VO2(A) and VO2(M) phases were respectively studied.

Preparation of Size Controllable BaTiO3 Nanoparticles in Microemulsion at Low Temperature

2014 ◽  
Vol 1004-1005 ◽  
pp. 63-68 ◽  
Author(s):  
Zhao Deng ◽  
Ying Dai ◽  
Hua Xiao ◽  
Meng Jun Zhou
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Low Temperature ◽  
Atmospheric Pressure ◽  
Tetrabutyl Titanate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molar Ratios ◽  
Transmission Electron ◽  
Barium Titanate Nanoparticles

Size controllable Barium titanate nanoparticles were synthesized in microemulsion consisting of water, OP-10, hexanol and cyclohexane under atmospheric pressure and low temperature, with Ba (OH)2·8H2O and tetrabutyl titanate used as starting reactants. Products were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX). The results show that 65°C is the proper temperature for the synthesis. The particle size can be controlled by varying the reactants’ concentration, ω value (molar ratios of water to surfactant) and aging time.

PREPARATION AND STRUCTURAL STUDY OF MECHANICAL ALLOYED OF Co50Fe20Cu2V8B20

2005 ◽  
Vol 19 (15n17) ◽  
pp. 2775-2779
Author(s):  
X. F. ZHANG ◽  
X. Q. HUANG ◽  
R. W. PENG ◽  
G. Q. WANG ◽  
S. Y. ZHANG
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Amorphous Alloys ◽  
Supercooled Liquid ◽  
Supercooled Liquid Region ◽  
Liquid Region ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron

The amorphous alloys of Co 50 Fe 20 Cu 2 V 8 B 20 are successfully obtained by using the mechanical alloying technique. The sample is analyzed by X-ray diffraction, transmission electron microscopy and differential scanning calorimetry. The DSC result of the powder sample milled for 120 h shows a complete amorphous phase and a wide supercooled liquid region (Tx - Tg ≃ 80 K ).

Hydrodeoxygenation of stearic acid for the production of “green” diesel

2014 ◽  
Vol 3 (6) ◽  
Author(s):  
Antonina A. Stepacheva ◽  
Linda Zh. Nikoshvili ◽  
Esther M. Sulman ◽  
Valentina G. Matveeva
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Photoelectron Spectroscopy ◽  
Hypercrosslinked Polystyrene ◽  
Biodiesel Production ◽  
Scanning Calorimetry ◽  
Green Diesel ◽  
X Ray ◽  
Transmission Electron

AbstractThe current work is devoted to the second-generation biodiesel production via fatty acids catalytic hydrodeoxygenation (HDO). Pd-containing catalysts based on polymeric matrix of hypercrosslinked polystyrene (HPS) with different metal loading were investigated in the process. The catalysts were characterized by low-temperature nitrogen physisorption, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The selectivity of the process (regarding to

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