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.

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.

Synthesis of Trilaminar Core–Shell Au/α-Fe2O3@SnO2Nanocomposites and their Application for Nonenzymatic Dopamine Electrochemical Sensing

NANO ◽  
2019 ◽  
Vol 14 (11) ◽  
pp. 1950138 ◽  
Author(s):  
Sai Zhang ◽  
Shijun Yue ◽  
Jiajia Li ◽  
Jianbin Zheng ◽  
Guojie Gao
Keyword(s):  
Electron Microscopy ◽  
High Sensitivity ◽  
Electrochemical Sensing ◽  
Synthesis Process ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Long Term Stability ◽  
Transmission Electron

Au nanoparticles anchored on core–shell [Formula: see text]-Fe2O3@SnO2 nanospindles were successfully constructed through hydrothermal synthesis process and used for fabricating a novel nonenzymatic dopamine (DA) sensor. The structure and morphology of the Au/[Formula: see text]-Fe2O3@SnO2 trilaminar nanohybrid film were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The electrochemical properties of the sensor were investigated by cyclic voltammetry and amperometry. The experimental results suggest that the composites have excellent catalytic property toward DA with a wide linear range from 0.5[Formula: see text][Formula: see text]M to 0.47[Formula: see text]mM, a low detection limit of 0.17[Formula: see text][Formula: see text]M (S/[Formula: see text]) and high sensitivity of 397.1[Formula: see text][Formula: see text]A[Formula: see text]mM[Formula: see text][Formula: see text]cm[Formula: see text]. In addition, the sensor exhibits long-term stability, good reproducibility and anti-interference.

Nanocrystallization of gas atomized Cu47Ti33Zr11Ni8Si1 metallic glass

2006 ◽  
Vol 21 (3) ◽  
pp. 597-607 ◽  
Author(s):  
S. Venkataraman ◽  
S. Scudino ◽  
J. Eckert ◽  
T. Gemming ◽  
C. Mickel ◽  
...  
Keyword(s):  
Metallic Glass ◽  
Primary Crystallization ◽  
Nanocrystalline Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
20 Nm ◽  
Annealing Experiments

Cu47Ti33Zr11Ni8Si1 metallic glass powder was prepared by gas atomization. Decomposition in the amorphous alloy and primary crystallization has been studied by differential scanning calorimetry (DSC), x-ray diffraction (XRD), and transmission electron microscopy (TEM). The glassy powder exhibits a broad DSC exotherm prior to bulk crystallization. Controlled annealing experiments reveal that this exotherm corresponds to a combination of structural relaxation and nanocrystallization. A uniform featureless amorphous contrast is observed in the TEM prior to the detection of nanocrystals of 4–6 nm in size. High-resolution TEM studies indicate that this nanocrystalline phase has a close crystallographic relationship with the γ–CuTi phase having a tetragonal structure. The product of the main crystallization event is also nanocrystalline, hexagonal Cu51Zr14, having dimensions of 20 nm. However, there is no evidence for possible amorphous phase separation prior to the nanocrystallization events.

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).

Structural Transitions in Titanium/Amorphous-Silicon Multilayers

1989 ◽  
Vol 163 ◽  
Author(s):  
E. Ma ◽  
L.A. Clevenger ◽  
C.V. Thompson ◽  
R.R. DeAvillez ◽  
K.N. Tu
Keyword(s):  
Thin Films ◽  
Exothermic Reaction ◽  
Heat Of Formation ◽  
Structural Transitions ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Calorimetric Analysis ◽  
Cross Sectional ◽  
X Ray ◽  
Transmission Electron

We report a quantitative investigation of silicidation in Ti/amorphous-Si thin-films using Differential Scanning Calorimetry (DSC), thin-film X-ray diffraction and Cross-sectional Transmission Electron Microscopy (XTEM). Multilayered thin films were used to facilitate calorimetric observation of the heat released or absorbed at many reacting interfaces. It is shown that calorimetric analysis, combined with structural analysis using X-ray diffraction and XTEM, is effective in providing both kinetic and thermodynamic information about interdiffusion reactions in thin films. The present paper describes experimental results for multilayers with an atomic concentration ratio of 1 Ti to 2 Si and modulation periods ranging from 10 to 60 nm. A thin amorphous titanium suicide layer was found to exist between the as-deposited Ti and a-Si layers. Heating the multilayer film caused the amorphous Ti-silicide to grow over a broad temperature range by an exothermic reaction. An endothermic relaxation occurs during the late stage of amorphous suicide growth. Heating to temperatures over 800K causes C49-TiSi2 to form at the a-si1icide/a-Si interface. Temperatures at which all the above structural transitions occur vary with modulation period. Analysis of the DSC data indicates an activation energy of 3.1 eV for the formation of C49-TiSio, which is attributed to both the nucleation and the early growth of the suicide. The heat of formation for C49-TiSi2 from a reaction of a-silicide and a-Si was found to be -30±5KJ/mol. Nucleation appears to be the controlling step in C49-TiSi2 formation.

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 A Comparison of “Bottom-Up” and “Top-Down” Approaches to the Synthesis of Pt/C Electrocatalysts

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 947
Author(s):  
Alexandra Kuriganova ◽  
Nikita Faddeev ◽  
Mikhail Gorshenkov ◽  
Dmitri Kuznetsov ◽  
Igor Leontyev ◽  
...  
Keyword(s):  
Alternating Current ◽  
X Ray Diffraction ◽  
Platinum Nanoparticle ◽  
X Ray ◽  
Transmission Electron ◽  
Electrochemically Active ◽  
Electrochemical Dispersion ◽  
The Stability ◽  
Nanoparticle Sizes

Three 40 wt % Pt/C electrocatalysts prepared using two different approaches—the polyol process and electrochemical dispersion of platinum under pulse alternating current—and a commercial Pt/C catalyst (Johnson Matthey prod.) were examined via X-ray diffraction (XRD) and transmission electron microscopy (TEM). The stability characteristics of the Pt/C catalysts were studied via long-term cycling, revealing that, for all cycling modes, the best stability was achieved for the Pt/C catalyst with the largest platinum nanoparticle sizes, which was synthesized via electrochemical dispersion of platinum under pulse alternating current. Our results show that the mass and specific electrocatalytic activities of Pt/C catalysts toward ethanol electrooxidation are determined by the value of the electrochemically active Pt surface area in the catalysts.

scholarly journals Crystallization Process and Microstructural Evolution of Melt Spun Al-RE-Ni-(Cu) Ribbons

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 443
Author(s):  
Francisco G. Cuevas ◽  
Sergio Lozano-Perez ◽  
Rosa María Aranda ◽  
Raquel Astacio
Keyword(s):  
Crystallization Process ◽  
Primary Crystallization ◽  
Amorphous Structure ◽  
Intermetallic Phases ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
Melt Spun ◽  
The Stability

The crystallization process, both at the initial and subsequent stages, of amorphous Al88-RE4-Ni8 alloys (RE = Y, Sm and Ce) has been studied. Additionally, the consequences of adding 1 at.% Cu replacing Ni or Al were studied. The stability of the amorphous structure in melt spun ribbons was thermally studied by differential scanning calorimetry, with Ce alloys being the most stable. The effect of Cu to reduce the nanocrystal size during primary crystallization was analyzed by transmission electron microscopy. This latter technique and x-ray diffraction showed the formation of intermetallic phases at higher temperatures. A clear difference was observed for the Ce alloy, with a simpler sequence involving the presence of Al3Ni and Al11Ce3. However, for the Y and Sm alloys, a more complex evolution involving metastable ternary phases before Al19RE5Ni3 appears, takes place. The shape of the intermetallics changes from equiaxial in the Ce alloys to elongate for Y and Sm, with longer particles for Sm and, in general, when Cu is added to the alloy.

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.

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