Hydrogenation Properties of Mg-Co and Its Related Alloys

2005 ◽  
Vol 475-479 ◽  
pp. 2453-2456
Author(s):  
Y. Zhang ◽  
Y. Tsushio ◽  
Hirotoshi Enoki ◽  
Etsuo Akiba
Keyword(s):  
Binary Alloys ◽  
Lattice Parameter ◽  
Ternary Alloys ◽  
Body Centered Cubic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Co Concentration ◽  
Bcc Structure ◽  
Co Alloys

Novel Mg-Co binary alloys with BCC (body-centered cubic) structure have been successfully synthesized by means of mechanical alloying technique. The formation of BCC structure was confirmed by X-ray diffraction and transmission electron microscopy. Mg-Co alloys were found in the range of Co concentration between 37 and 80 atomic %. All the Mg-Co alloys synthesized absorbed hydrogen below 373K. The maximum hydrogen capacity of these alloys reaches 2.7 mass %. However, desorption of hydrogen at 373 K has not been observed yet. Mg- Co-X (X = B and Ni) ternary alloys with BCC structure have also been synthesized. The lattice parameter of both alloys is lower than that of Mg-Co binary alloys, meanwhile the maximum hydrogen content of both alloys also decreased.

Multicomponent metastable phase formed by crystallization of Ti–Ni–Cu–Sn–Zr amorphous alloy

1999 ◽  
Vol 14 (11) ◽  
pp. 4426-4430 ◽  
Author(s):  
Dmitri V. Louzguine ◽  
Akihisa Inoue
Keyword(s):  
Metastable Phase ◽  
Exothermic Reaction ◽  
Primary Crystallization ◽  
Lattice Parameter ◽  
Body Centered Cubic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Unknown Phase ◽  
Transmission Electron

Crystallization of the Ti45Ni20Cu25Sn5Zr5 alloy has been studied by means of scanning differential calorimetry, x-ray diffraction, and conventional and high-resolution transmission electron microscopy. The first stage at about 750–800 K is related to the primary crystallization of the Ti8Ni3Cu3SnZr metastable phase having Im3m body-centered-cubic structure with a lattice parameter of a = 0.3069 nm followed by precipitation of the secondary dotlike phase precipitates on its boundaries. The activation energy for the first exothermic reaction determined by Kissinger analysis was found to be 310 kJ/mol. CuTi, Ni2TiZr, and an unknown phase are formed during long-term annealing at high (more than 850 K) temperature.

Structure of CoxAg100-x and Its Relation to GMR

1992 ◽  
Vol 286 ◽  
Author(s):  
John Q. Xiao ◽  
J. Samuel ◽  
C. L. Chien
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Composition Range ◽  
Magnetic Scattering ◽  
Granular System ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Co Concentration

ABSTRACTWe have studied the structure of the Co-Ag granular system across the entire composition range, as well as the annealed samples, using transmission electron microscopy (TEM) and x-ray diffraction. GMR, as much as 80% at 5K and 25% at room temperature, have been observed. The absolute values of the resistivity (ρ) and the change of the resistivity (δρ) as functions of the magnetic Co concentration and the annealing temperature have been determined. A linear relation between δρ and I/rco, where rco is Co particle size, has been found. This result suggests that the magnetic scattering at the interfaces is crucial to GMR.

OPTICAL AND STRUCTURAL PROPERTIES OF Ag NANOPARTICLES Eu OXIDE FILMS

2008 ◽  
Vol 07 (06) ◽  
pp. 339-344 ◽  
Author(s):  
A. A. DAKHEL
Keyword(s):  
Lattice Parameter ◽  
Europium Oxide ◽  
Silicon Substrates ◽  
Ag Nanoparticle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nanoparticle Radius ◽  
Different Temperatures ◽  
Bcc Structure ◽  
The Eu

Silver-incorporated europium oxide thin films have been prepared by the successive evaporation method on quartz and silicon substrates. The silver concentration was 2.5% and 8.9% respectively, as measured by X-ray fluorescence. X-ray diffraction revealed that the Eu oxide of these samples remained amorphous after preannealing at 450°C; however, it crystallized in bcc structure at 800°C. The lattice parameter of the crystallized Eu oxide was larger than that of the bulk, due to the adsorption of Ag + ions, which have a higher ionic radius. The optical absorption of the samples manifested the surface plasmon resonance (SPR) phenomenon, which varied with the Ag content and preannealings of the samples at different temperatures. The Ag nanoparticle radius was estimated with the Mie classical theory by using the SPR data analysis.

Morphological and structural evolutions of nonequilibrium titanium-nitride alloy powders produced by reactive ball milling

1992 ◽  
Vol 7 (4) ◽  
pp. 888-893 ◽  
Author(s):  
M. Sherif El-Eskandarany ◽  
K. Sumiyama ◽  
K. Aoki ◽  
K. Suzuki
Keyword(s):  
Electron Microscopy ◽  
Titanium Nitride ◽  
Gas Flow ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Nitrogen Gas ◽  
X Ray ◽  
Grain Sizes ◽  
Transmission Electron

Nonequilibrium titanium-nitride alloy powders have been fabricated by a high energetic ball mill under nitrogen gas flow at room temperature and characterized by means of x-ray diffraction, scanning electron microscopy, transmission electron microscopy, and differential scanning calorimetry. Initial hcp titanium is completely transformed to nonequilibrium-fcc Ti–N after 720 ks of the milling time. The fcc Ti–N phase is stable at relatively low temperature and transforms at 855 K to Ti2N and δ phases. At the final stage of milling, the particle- and grain-sizes of alloy powders are 1 mm and 5 nm, respectively, and the lattice parameter is 0.419 nm.

The Nucleation and Propagation of Misfit Dislocations aear the Critical Thickness in Ge-Si Strained Epilayers

1987 ◽  
Vol 104 ◽  
Author(s):  
E. P. Kvam ◽  
D. J. Eaglesham ◽  
D. M. Maher ◽  
C. J. Humphreys ◽  
J. C. Bean ◽  
...  
Keyword(s):  
Lattice Parameter ◽  
Dislocation Segment ◽  
Misfit Dislocations ◽  
X Ray Diffraction ◽  
Parameter Mismatch ◽  
Growth Interface ◽  
Edge Type ◽  
X Ray ◽  
Transmission Electron ◽  
Dislocation Behavior

ABSTRACTThe nucleation and propagation of misfit dislocations in Ge-Si strained epilayers on (100) Si have been investigated using transmission electron microscopy and X-ray diffraction topography at low lattice parameter mismatch (˜ 0.8%). Misfit dislocations nucleate as half loops which are predominantly unfaulted (> 90%) at the advancing growth interface. Under the driving force of the epilayer strain, unfaulted half loops glide and expand on inclined { 111 }planes toward the heterointerface (i.e. substrate/epilayer interface). These unfaulted half loops consist of a 60°-dislocation segment which lies along < 011> in a plane parallel to the heterointerface (i.e. (100)) and this segment is connected to the growth interface by two screw dislocation segments which both lie on the same inclined {111} glide plane. As 60° dislocations reach the heterointerface on each of the four inclined {111} variants, they form an orthogonal array of misfit dislocations which lie along [011] and [011]. At higher lattice parameter mismatch (˜ 2%), there appear to be some important changes in the dislocation behavior and these changes result in orthogonal arrays of heterointerface dislocations which are predominantly edge type (i.e. 90°dislocations).

A Novel Route to Prepare Titanium Doped Mesoporous Carbon

2014 ◽  
Vol 936 ◽  
pp. 476-479
Author(s):  
Hao Tian ◽  
Yan Zhang ◽  
Yun Jiang Liu
Keyword(s):  
Titanium Content ◽  
Mesoporous Carbons ◽  
Body Centered Cubic ◽  
X Ray Diffraction ◽  
Ordered Mesoporous Carbons ◽  
X Ray ◽  
Transmission Electron ◽  
Ordered Mesoporous ◽  
Cubic Structure ◽  
First Time

A series of titanium doped ordered mesoporous carbons (Ti-OMCs) were prepared by employing titanium modified resol as source for the first time. The effect of titanium content and F127 content on the microstructure of Ti-OMCs was investigated by X-ray diffraction (XRD), N2 sorption isothermal and Transmission electron microscopy (TEM). The results showed that regularity of products decreased with the increase of titanium content. A mesophase transformation from 2-D hexagonal (P6mm) to body-centered cubic () structure can be achieved by decreasing F127 content.

scholarly journals Zn2+ substituted superparamagnetic MgFe2O4 spinel-ferrites: Investigations on structural and spin-interactions

2020 ◽  
Vol 9 (5) ◽  
pp. 576-587
Author(s):  
Lakshita Phor ◽  
Surjeet Chahal ◽  
Vinod Kumar
Keyword(s):  
Photoelectron Spectroscopy ◽  
Spinel Phase ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Spin Interactions ◽  
Transmission Electron ◽  
Maximum Magnetization ◽  
Zn Content

Abstract Nano-magnetic ferrites with composition Mg1−xZnxFe2O4 (x = 0.3, 0.4, 0.5, 0.6, and 0.7) have been prepared by coprecipitation method. X-ray diffraction (XRD) studies showed that the lattice parameter was found to increase from 8.402 to 8.424 Å with Zn2+ ion content from 0.3 to 0.7. Fourier transform infrared (FTIR) spectra revealed two prominent peaks corresponding to tetrahedral and octahedral at around 560 and 430 cm−1 respectively that confirmed the spinel phase of the samples. Transmission electron microscopy (TEM) images showed that the particle size was noted to increase from 18 to 24 nm with an increase in Zn content from x = 0.3 to 0.7. The magnetic properties were studied by vibrating sample magnetometer (VSM) and electron paramagnetic resonance (EPR) which ascertained the superparamagnetic behavior of the samples and contribution of superexchange interactions. The maximum magnetization was found to vary from 23.80 to 32.78 emu/g that increased till x = 0.5 and decreased thereafter. Further, X-ray photoelectron spectroscopy (XPS) was employed to investigate the chemical composition and substantiate their oxidation states.

scholarly journals Nanoindentation and Adhesion Properties of Ta Thin Films

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Yuan-Tsung Chen
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Protective Layer ◽  
Body Centered Cubic ◽  
X Ray Diffraction ◽  
Adhesion Properties ◽  
X Ray ◽  
Mean Grain Size ◽  
Bcc Structure ◽  
Deposited Films

Ta films were sputtered onto a glass substrate with thicknesses from 500 Å to 1500 Å under the following conditions: (a) as-deposited films were maintained at room temperature (RT), (b) films were postannealed atTA=150°C for 1 h, and (c) films were postannealed atTA=250°C for 1 h. X-ray diffraction (XRD) results revealed that the Ta films had a body-centered cubic (BCC) structure. Postannealing conditions and thicker Ta films exhibited a stronger Ta (110) crystallization than as-deposited and thinner films. The nanoindention results revealed that Ta thin films are sensitive to mean grain size, including a valuable hardness (H) and Young’s modulus (E). High nanomechanical properties of as-deposited and thinner films can be investigated by grain refinement, which is consistent with the Hall-Petch effect. The surface energy of as-deposited Ta films was higher than that in postannealing treatments. The adhesion of as-deposited Ta films was stronger than postannealing treatments because of crystalline degree effect. The maximalHandEand the optimal adhesion of an as-deposited 500-Å-thick Ta film were 15.6 GPa, 180 GPa, and 51.56 mJ/mm2, respectively, suggesting that a 500-Å-thick Ta thin film can be used in seed and protective layer applications.

Novel Process for Synthesizing Nano-Ceramics Powder: Mechanical & Thermal Activation Processing

2007 ◽  
Vol 280-283 ◽  
pp. 581-586 ◽  
Author(s):  
Xiao Long Cui ◽  
Li Shan Cui
Keyword(s):  
Electron Microscopy ◽  
Mechanical Activation ◽  
Thermal Activation ◽  
Processing Time ◽  
Lattice Parameter ◽  
Synthesis Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

A novel process for synthesizing nano-ceramics powders, named Mechanical & Thermal Activation Processing, is discussed in the present paper. Dissimilar with the tradition processing of mechanical activation or mechanochemistry, the processing is based on thermal activation in liquid phase (molten salt) after mechanical activation. The synthesizing of nanometer sized TiC particles by the method was investigated. The end product has been analyzed by X-ray diffraction (XRD),transmission electron microscope (TEM), scanning electron microscopy (SEM) and energy dispersion X-ray (EDX). The results show that nano-meter sized particles were formed, and the lattice parameter of TiC is close to the value of non-oxygen TiC. Compared with usually methods, the whole processing time needed is shortened; moreover, the synthesis temperature could be reduced 500°C. The mechanism for mechanical & yhermal activation is discussed.

Nano body-centered cubic CoFe2alloy precursor for cobalt ferrite via sonoreduction process

2008 ◽  
Vol 23 (7) ◽  
pp. 1849-1853 ◽  
Author(s):  
Maya Mohan ◽  
Vimlesh Chandra ◽  
S. Sundar Manoharan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cobalt Ferrite ◽  
Alloy Composition ◽  
Body Centered Cubic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Bcc Phase ◽  
Potential Precursor

A stable nano body-centered cubic (bcc) CoFe2alloy was isolated by employing a combination of N2H4.H2O reduction and sonochemical route under basic conditions. This alloy has proved to be a potential precursor for CoFe2O4production. X-ray diffraction and transmission electron microscopy confirms the formation of a bcc phase CoFe2alloy with particle size <10 nm and spherical morphology. Thermogravimetric analysis confirmed the oxidation of the alloy composition showing a weight gain between 200 and 500 °C, which corresponds to fully oxidized CoFe2O4. A significant increase in the saturation magnetization (Ms= 230 emu/g) for the nano CoFe2alloy was observed in comparison with that of the theoretical bulk value (200 emu/g) at 300 K.

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