X-ray diffraction and microstructural studies in 2 : 17 type Sm–Co magnetic alloys containing Fe, Cu, and Zr

1999 ◽  
Vol 14 (6) ◽  
pp. 2430-2435 ◽  
Author(s):  
R. Gopalan ◽  
T. S. R. K. Sastry ◽  
A. K. Singh ◽  
V. Chandrasekaran
Keyword(s):  
Single Phase ◽  
Solution Treatment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Rhombohedral Crystal Structure ◽  
Cast Alloys ◽  
Rhombohedral Crystal ◽  
Co Alloys ◽  
Microstructural Studies

X-ray diffraction and microstructural studies were carried out on 2 : 17 type Sm–Co alloys containing Fe, Cu, and Zr (13–14 at.% Sm, 57–60 at.% Co, 20–22 at.% Fe, 4 at.% Cu, and 3 at.% Zr) in as-cast and heat-treated conditions. Microstructural studies revealed that the as-cast alloys contain three phases. It was observed that the samples subjected to sintering at 1463 K for 45 min followed by a solution treatment at 1448 K for 1 h resulted in nearly a single-phase, rhombohedral crystal structure (Th2Zn17-type). Subsequent isothermal aging at 1123 K and ramp-cooling to 673 K resulted in a mixture of Sm2Co17- and SmCo5-type phases with the former as major phase. It was also found that samples (Sm > 13 at.%) sintered at temperatures >1463 K showed incipient melting and multiphase formation.

Microwave-Assisted Solution Combustion Synthesis and Characterization of Thermoelectric Ca3Co2O6 Powders

2013 ◽  
Vol 802 ◽  
pp. 84-88
Author(s):  
Sagulthai Kahatta ◽  
Nopsiri Chaiyo ◽  
Chesta Ruttanapun ◽  
Wicharn Techitdheera ◽  
Wisanu Pecharapa ◽  
...  
Keyword(s):  
Combustion Synthesis ◽  
Solution Combustion Synthesis ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Solution Combustion ◽  
X Ray ◽  
Microwave Assisted ◽  
Product Characterization ◽  
Rhombohedral Crystal Structure ◽  
Rhombohedral Crystal

The microwave-assisted solution combustion synthesis was applied to the initial synthesizing of Ca3Co2O6powder using glycine as a fuel and nitrate as an oxidant. The as-synthesized powders were calcined at 700-1,000ºC for 4h. Product characterization was performed using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and Scanning electron microscope (SEM). The fuel-to-oxidizer molar ratio was found to affect the combustion reaction and character of the powder obtained. The phase composition of powder after calcination at various temperatures has shown that the formation of Ca3Co2O6occurs directly. The calcined powder possesses a rhombohedral crystal structure with an X-ray diffraction pattern that could be matched with the Ca3Co2O6JCPDS: 89-0629. This method is a simple way of synthesizing fine Ca3Co2O6powder with a low calcination temperature.

The Transformation of Co-Rich Alloys Produced by Mechanical Alloying

2006 ◽  
Vol 509 ◽  
pp. 135-140
Author(s):  
Francisco Cruz-Gandarilla ◽  
R. Gayosso-Armenta ◽  
J. Gerardo Cabañas-Moreno ◽  
Heberto Balmori-Ramírez
Keyword(s):  
Single Phase ◽  
Intermetallic Phase ◽  
High Energy ◽  
Inert Atmosphere ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
Powder Mixtures ◽  
X Ray ◽  
Heat Treated ◽  
Energy Ball

Elemental powder mixtures of Co and Ti were subjected to high-energy ball milling in order to produce mechanically alloyed powders with nominal compositions Co64Ti36, Co67Ti33, Co70Ti30, Co73Ti27, Co76Ti24 and Co85Ti15. The mechanically alloyed powders were treated during 30 minutes in inert atmosphere at temperatures in the range 300 – 700 °C. Both the as-milled powders as well as those subjected to heat treatments have been characterized by x-ray diffraction, scanning electron microscopy, energy-dispersive x-ray spectrometry and differential thermal analysis. As-milled products consist mostly of agglomerated powders with a size between 10 and 80 µm which give an amorphous-like diffraction pattern, except for the Co85Ti15 sample whose pattern presents the characteristic peaks of the Co3Ti intermetallic phase. The transformation of the asmilled powders occurs at temperatures in the range of about 530 – 670 °C with clearly observed exothermic events. The Co3Ti phase is found in all heat treated samples, together with fcc-Co (in Co76Ti24 and Co85Ti15) or the hexagonal Co2Ti intermetallic phase (in Co64Ti36, Co67Ti33 and Co70Ti30); the Co73Ti27 sample was essentially single-phase Co3Ti after heating to 700 °C. Our results suggest the occurrence of crystallization of an amorphous phase in two overlapping stages during heating of the mechanically alloyed powders.

Magnetic and Magnetostrictive Properties of Tb-Dy-Ho-Fe-Co Alloys

2009 ◽  
Vol 152-153 ◽  
pp. 7-10 ◽  
Author(s):  
Irina S. Tereshina ◽  
S.A. Nikitin ◽  
G.A. Politova ◽  
A.S. Ilyushin ◽  
A.A. Opolenko ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Rare Earth ◽  
Applied Magnetic Field ◽  
Single Phase ◽  
X Ray Diffraction ◽  
Standard Strain ◽  
X Ray ◽  
Structural And Magnetic Properties ◽  
Co Alloys

In this work, the structural and magnetic properties of single-phase TbxDyyHoz(Fe,Co)2 (x + y + z = 1) alloys have been investigated by means of X-ray diffraction, 57Fe Mossbauer spectroscopy, magnetization measurements and a standard strain gage technique. The magnetostriction of TbxDyyHoz(Fe,Co)2 was examined against an applied magnetic field up to 10 kOe in 80 - 400 K temperature range. The Co-containing compounds are found to have high values of magnetostrictive susceptibility due to compensation of magnetic anisotropy in both the rare-earth and 3d transition metals sublattices.

Synthesis of Ternary Semiconductor Silver Bismuth Telluride by Chemical Bath Deposition

2017 ◽  
Vol 751 ◽  
pp. 489-493 ◽  
Author(s):  
Patamaporn Termsaithong ◽  
Aphichart Rodchanarowan
Keyword(s):  
Chemical Bath Deposition ◽  
Bismuth Telluride ◽  
X Ray Diffraction ◽  
Solar Cell Application ◽  
X Ray ◽  
Rhombohedral Crystal Structure ◽  
Rhombohedral Crystal ◽  
Ternary Semiconductor ◽  
Cbd Method ◽  
Scanning Electron

In this study, the synthesis of the ternary semiconductor sensitized silver bismuth telluride (AgBiTe2: SBT) particles was produced in the solution of AgNO3, Bi (NO3)3×5H2O and Na2O3Te by using a chemical bath deposition (CBD) method and annealing at 200°C for 1 h. According to scanning electron microscopy (SEM), the particle size of SBT after annealing was bigger than before annealing. Based on X-ray diffraction, the SBT after annealing for 1h became more crystalline. In addition, the XRF data also demonstrated that the SBT powder consists of Ag, Bi, and Te as dominant elements. The XRD result confirms a successful growth of the SBT particles with rhombohedral crystal structure. Based on the obtaining results, the SBT particles were successfully synthesized and potentially applied for solar cell application.

An XRD Phase Analysis of Al-F Re-Deposition Produced from Reactive Ion Etching

2015 ◽  
Vol 659 ◽  
pp. 575-579
Author(s):  
Chu Pong Pakpum
Keyword(s):  
Plasma Etching ◽  
Alpha Phase ◽  
Chemical Formula ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rhombohedral Crystal Structure ◽  
Xrd Phase Analysis ◽  
Rhombohedral Crystal ◽  
Composition Structure ◽  
Scanning Electron

This paper reports the analysis of the composition, structure and phase of the re-deposition material that was generated from the reaction from CF4 plasma etching on the Al2O3-TiC substrate. The re-deposition was sputtered from the etching area and deposited on a silicon coupon for analysis. The morphology of the re-deposition was investigated by scanning electron microscope (SEM) and the composite element of the re-deposition was detected by using energy dispersive x-ray spectroscopy (SEM-EDX). X-ray diffraction (XRD) was used to analyse the structure and phase of the re-deposition. The results show that the prepared re-deposition was composed of F and Al atoms, with 51.24 At% and 27.67 At%, respectively. XRD revealed that this was owing to the chemical formula AlF3, which has a rhombohedral crystal structure in the most stable alpha phase (α-AlF3).

scholarly journals Investigation on structural, dielectric and ferroelectric properties of samarium-substituted BiFeO3–PbTiO3 composites

2017 ◽  
Vol 07 (01) ◽  
pp. 1750001 ◽  
Author(s):  
Truptimayee Sahu ◽  
Banarji Behera
Keyword(s):  
High Temperature ◽  
Thermal Activation ◽  
Room Temperature ◽  
Ferroelectric Properties ◽  
X Ray Diffraction ◽  
Solid State Reaction Technique ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Rhombohedral Crystal Structure ◽  
Rhombohedral Crystal

The polycrystalline samples of 0.8BiSmxFe[Formula: see text]O3–0.2PbTiO3 ([Formula: see text] and 0.20) were prepared by using the conventional solid-state reaction technique and sintered at high temperature (850[Formula: see text]C). X-ray diffraction (XRD) confirms the distorted rhombohedral crystal structure for all the composites at room temperature. The surface morphology was checked by field-emission scanning electron microscope (FESEM) technique and homogeneous mixing of the components was confirmed by energy-dispersive analysis of X-ray (EDAX). The detailed study of dielectric properties of the composites reveals an increasing nature of dielectric constant ([Formula: see text]) and loss tangent (tan[Formula: see text]) with the increase of temperature due to thermal activation. The Arrhenius plots of temperature dependence of AC conductivity yield the activation energy within the material at high-temperature range. The ferroelectric study shows that the remnant polarization decreases with the increase of Samarium (Sm) concentration.

Raman And Fluorescence Spectra Observed in Laser Microprobe Measurements of Several Compositions in the Ln-Ba-Cu-O System

1990 ◽  
Vol 48 (2) ◽  
pp. 278-279
Author(s):  
Edgar S. Etz ◽  
Thomas D. Schroeder ◽  
Winnie Wong-Ng
Keyword(s):  
Fluorescence Spectra ◽  
Single Phase ◽  
X Ray Diffraction ◽  
Ceramic Powders ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Raman Microprobe ◽  
Methods Of Synthesis ◽  
Compositional Homogeneity ◽  
Processing Techniques

We are investigating by Raman microprobe measurements the superconducting and related phases in the LnBa2Cu3O7-x (for x=0 to 1) system where yttrium has been replaced by several of the lanthanide (Ln = Nd,Sm,Eu,Ho,Er) elements. The aim is to relate the observed optical spectra (Raman and fluorescence) to the compositional and structural properties of these solids as part of comprehensive materials characterization. The results are correlated with the methods of synthesis, the processing techniques of these materials, and their superconducting properties. Of relevance is the substitutional chemistry of these isostructural systems, the differences in the spectra, and their microanalytical usefulness for the detection of impurity phases, and the assessment of compositional homogeneity. The Raman spectra of most of these compounds are well understood from accounts in the literature.The materials examined here are mostly ceramic powders prepared by conventional solid state reaction techniques. The bulk samples are of nominally single-phase composition as determined by x-ray diffraction.

Observation of pseudo 10-fold symmetry in the ordered iron-zinc delta phase

1992 ◽  
Vol 50 (1) ◽  
pp. 36-37
Author(s):  
L. A. Giannuzzi ◽  
A. S. Ramani ◽  
P. R. Howell ◽  
H. W. Pickering ◽  
W. R. Bitler
Keyword(s):  
Single Phase ◽  
X Ray Diffraction ◽  
Rich Region ◽  
Average Cell ◽  
X Ray ◽  
Delta Phase ◽  
Cell Dimensions ◽  
Δ Phase ◽  
Morphological Differences ◽  
Concentration Discontinuity

The δ phase is a Zn-rich intermetallic, having a composition range of ∼ 86.5 - 92.0 atomic percent Zn, and is stable up to 665°C. The stoichiometry of the δ phase has been reported as FeZn7 and FeZn10 The deviation in stoichiometry can be attributed to variations in alloy composition used by each investigator. The structure of the δ phase, as determined by powder x-ray diffraction, is hexagonal (P63mc or P63/mmc) with cell dimensions a = 1.28 nm, c = 5.76 nm, and 555±8 atoms per unit cell. Later work suggested that the layer produced by hot-dip galvanizing should be considered as two distinct phases which are characterized by their morphological differences, namely: the iron-rich region with a compact appearance (δk) and the zinc-rich region with a columnar or palisade microstructure (δp). The sub-division of the δ phase was also based on differences in diffusion behavior, and a concentration discontinuity across the δp/δk boundary. However, work utilizing Weisenberg photographs on δ single crystals reported that the variation in lattice parameters with composition was small and hence, structurally, the δk phase and the δp phase were the same and should be thought of as a single phase, δ. Bastin et al. determined the average cell dimensions to be a = 1.28 nm and c = 5.71 nm, and suggested that perhaps some kind of ordering process, which would not be observed by x-ray diffraction, may be responsible for the morphological differences within the δ phase.

scholarly journals Stable and Metastable Phase Equilibria Involving the Cu6Sn5 Intermetallic

2021 ◽  
Author(s):  
A. Leineweber ◽  
M. Löffler ◽  
S. Martin
Keyword(s):  
Phase Equilibria ◽  
Electron Backscatter Diffraction ◽  
Metastable Phase ◽  
Stable Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Ordered Phases ◽  
Backscatter Diffraction ◽  
Kinetics Of

Abstract Cu6Sn5 intermetallic occurs in the form of differently ordered phases η, η′ and η′′. In solder joints, this intermetallic can undergo changes in composition and the state of order without or while interacting with excess Cu and excess Sn in the system, potentially giving rise to detrimental changes in the mechanical properties of the solder. In order to study such processes in fundamental detail and to get more detailed information about the metastable and stable phase equilibria, model alloys consisting of Cu3Sn + Cu6Sn5 as well as Cu6Sn5 + Sn-rich melt were heat treated. Powder x-ray diffraction and scanning electron microscopy supplemented by electron backscatter diffraction were used to investigate the structural and microstructural changes. It was shown that Sn-poor η can increase its Sn content by Cu3Sn precipitation at grain boundaries or by uptake of Sn from the Sn-rich melt. From the kinetics of the former process at 513 K and the grain size of the η phase, we obtained an interdiffusion coefficient in η of (3 ± 1) × 10−16 m2 s−1. Comparison of this value with literature data implies that this value reflects pure volume (inter)diffusion, while Cu6Sn5 growth at low temperature is typically strongly influenced by grain-boundary diffusion. These investigations also confirm that η′′ forming below a composition-dependent transus temperature gradually enriches in Sn content, confirming that Sn-poor η′′ is metastable against decomposition into Cu3Sn and more Sn-rich η or (at lower temperatures) η′. Graphic Abstract

scholarly journals Preparation of high-entropy carbides by different sintering techniques

2021 ◽  
Vol 56 (19) ◽  
pp. 11237-11247 ◽  
Author(s):  
Johannes Pötschke ◽  
Manisha Dahal ◽  
Mathias Herrmann ◽  
Anne Vornberger ◽  
Björn Matthey ◽  
...  
Keyword(s):  
Grain Size ◽  
Single Phase ◽  
X Ray Diffraction ◽  
Vacuum Sintering ◽  
X Ray ◽  
High Entropy ◽  
Mean Grain Size ◽  
The Mean ◽  
Gas Pressure Sintering ◽  
Hardness Values

AbstractDense (Hf, Ta, Nb, Ti, V)C- and (Ta, Nb, Ti, V, W)C-based high-entropy carbides (HEC) were produced by three different sintering techniques: gas pressure sintering/sinter–HIP at 1900 °C and 100 bar Ar, vacuum sintering at 2250 °C and 0.001 bar as well as SPS/FAST at 2000 °C and 60 MPa pressure. The relative density varied from 97.9 to 100%, with SPS producing 100% dense samples with both compositions. Grain size measurements showed that the substitution of Hf with W leads to an increase in the mean grain size of 5–10 times the size of the (Hf, Ta, Nb, Ti, V,)C samples. Vacuum-sintered samples showed uniform grain size distribution regardless of composition. EDS mapping revealed the formation of a solid solution with no intermetallic phases or element clustering. X-ray diffraction analysis showed the structure of mostly single-phase cubic high-entropy carbides. Hardness measurements revealed that (Hf, Ta, Nb, Ti, V)C samples possess higher hardness values than (Ta, Nb, Ti, V, W)C samples.

Sign in / Sign up

Export Citation Format

Share Document