Stoichiometry and Alloying Effects on the Phase Stability and Mechanical Properties of TiCr2-Base Laves Phase Alloys

1994 ◽  
Vol 364 ◽  
Author(s):  
Katherine C. Chen ◽  
Samuel M. Allen ◽  
James D. Livingston
Keyword(s):  
Fracture Toughness ◽  
Single Phase ◽  
Lattice Parameter ◽  
Phase Region ◽  
X Ray Diffraction ◽  
X Ray ◽  
Composition Effects ◽  
Different Temperatures ◽  
Diffraction Lattice ◽  
Alloying Effects

AbstractTi-Cr alloys near the TiCr2 composition have been studied to determine the single-phase Laves field and the associated defects accompanying off-stoichiometry. A combination of metallography, x-ray diffraction, lattice parameter measurements, density measurements and electron microprobe analysis have been used to establish a narrow single-phase region extending towards Ti-rich compositions. All three Laves crystal structures (C14, C36 and C15) were found to exist at different temperatures. Hardness and fracture toughness values determined by Vickers microindentation were studied as a function of alloy composition. Effects of adding Fe, Nb, Mo, and V to TiCr2 on lattice parameter, crystal structure, hardness and fracture toughness are reported.

Preparation of Ultra–Fine La3NbO7 Powder by Solid State Reaction

2012 ◽  
Vol 512-515 ◽  
pp. 158-161 ◽  
Author(s):  
Ling Dai ◽  
Qiang Xu ◽  
Shi Zhen Zhu ◽  
Ling Liu
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Single Phase ◽  
Thermal Barrier ◽  
X Ray Diffraction ◽  
X Ray ◽  
Granular Particle ◽  
Fine Particle Size ◽  
Ultra Fine Particle ◽  
Different Temperatures

As a new candidate material for the ceramic layer in thermal barrier coatings (TBCs) system, La3NbO7 was synthesized with La2O3 powder and Nb2O5 powder by solid state reaction. The stating powders with a mole ratio of La to Nb of 3:1 were mixed and then the mixture was calcined under the different temperatures(800°C, 1000°C, 1200°C) and dwell times(2h, 6h, 10h). The phase structure of the powder was observed by X–ray diffraction(XRD), and the microstructure of the sample was observed by scanning electron microscope(SEM). The effect of calcination temperature and dwell Time on the phase formation were examined. The results indicate that the La3NbO7 powder with single phase can be synthesized successfully at 1200°C for 10h in air, and the La3NbOsub>7 powders synthesized have an ultra-fine particle size of 0.5˜1µm with a granular particle shape. With the temperature increasing, LaNbO4/sub> was synthesized firstly and then La3NbO7 was synthesized with a mole ratio of La2O3 to LaNbO4 of 1:1.

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.

INFLUENCE OF SAMARIUM SUBSTITUTION ON IMPEDANCE DIELECTRIC AND ELECTROMECHANICAL PROPERTIES OF Pb(1-x)K2xNb2O6

2007 ◽  
Vol 21 (06) ◽  
pp. 931-945 ◽  
Author(s):  
K. SAMBASIVA RAO ◽  
P. MURALI KRISHNA ◽  
D. MADHAVA PRASAD ◽  
JOON HYUNG LEE
Keyword(s):  
Impedance Spectroscopy ◽  
Room Temperature ◽  
Single Phase ◽  
Piezoelectric Properties ◽  
Orthorhombic Structure ◽  
X Ray Diffraction ◽  
Electromechanical Properties ◽  
X Ray ◽  
Different Temperatures ◽  
Ferroelectric Hysteresis

Ferroelectric, hysteresis, impedance spectroscopy parameters, AC conductivity, and piezoelectric properties in the ceramics of Pb 0.74 K 0.52 Nb 2 O 6 and Pb 0.74 K 0.13 Sm 0.13 Nb 2 O 6 have been studied. X-ray diffraction study reveals single phase with the orthorhombic structure. The samples were characterized for ferroelectric and impedance spectroscopy properties from room temperature to 600°C. Cole–Cole plots (Z″ versus Z′) are drawn at different temperatures. The results obtained are analyzed to understand the conductivity mechanism in both the samples. The piezoelectric constant d33 has been found to be 96 × 10-12 C/N in PKN.

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.

scholarly journals Phase Analysis of Bio-Based Derived Tricalcium Disilicate From 2CaO:1SiO2 By X-ray Diffraction

2021 ◽  
Vol 2129 (1) ◽  
pp. 012054
Author(s):  
Siti Nur Hazwani Yunus ◽  
Khor Shing Fhan ◽  
Banjuraizah Johar ◽  
Nur Maizatul Shima Adzali ◽  
Nur Hazlinda Jakfar ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Rice Husk ◽  
Single Phase ◽  
Sintering Temperature ◽  
Rietveld Analysis ◽  
Dicalcium Silicate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Temperatures ◽  
Complete Formation

Abstract In this paper, tricalcium disilicate was formed from dicalcium silicate compound powder, synthesised via a mechanochemical technique using a stoichiometric 2CaO:1SiO2. Compound CaO and SiO2 were derived from the bio-waste of eggshell and rice husk at the calcination temperature of 900°C and 800°C, respectively. The dicalcium disilicate powder was sintered for 2 hours at different temperatures ranging from 1150°C to 1350°C. Using X-ray diffraction with Rietveld analysis, it was found that the amount of tricalcium disilicate with monoclinic (beta) crystal structure increases on sintering temperature at the expense of dicalcium silicate. The complete formation of single-phase tricalcium disilicate began at a sintering temperature of 1300°C. The effect of sintering temperatures on the crystallisation and phase transition of dicalcium silicate is reported. The size of crystallites depends on the sintering temperature. The finding of this study rebound to the benefit of society by reducing the risk-off pollution cause by accessive redundant bio-waste eggshell and rice husk and also reduced the amount of CaO and SiO2 used in the fabrication of Ca3Si2O7.

scholarly journals X-ray, IR and SEM studies on some Li-Cd ferrites

YMER Digital ◽  
2021 ◽  
Vol 20 (12) ◽  
pp. 333-340
Author(s):  
Sudhir Kulkarni ◽  
Keyword(s):  
Grain Size ◽  
Room Temperature ◽  
Single Phase ◽  
Lattice Parameter ◽  
Lithium Ferrite ◽  
Cadmium Content ◽  
X Ray Diffraction ◽  
Ceramic Method ◽  
X Ray ◽  
Single Phase Formation

Lithium-Cadmium ferrites with general formula Li0.5-x/2 Fe2.5-x/2 Cdx O4 (with x = 0,0.1,0.2....,0.7) were prepared by standard ceramic method. X-ray diffraction studies confirms single phase formation and lattice parameters were calculated. The crystal structure is cubic and lattice parameter increases with increasing Cd content. The infrared absorption (IR) spectra of all the samples were recorded in the range 200-800 cm-1 at room temperature in the KBr medium. Lithium ferrite shows four principal bands and some shoulders have been observed. The force constants Kt and Ko were calculated using Waldron's analysis. Scanning electron microscopy studies shows increase in grain size up to x = 0.1 and then the grain size decreases with increase in cadmium content.

The Structure and Electric Field Dependent Dielectric Properties of Annealed Sr1−xBaxTio3 Ferroelectric Thin Films

1995 ◽  
Vol 401 ◽  
Author(s):  
L.A. Knauss ◽  
J.M. Pond ◽  
J.S. Horwitz ◽  
C.H. Mueller ◽  
R.E. Treece ◽  
...  
Keyword(s):  
Thin Films ◽  
Dielectric Properties ◽  
Single Phase ◽  
Pulsed Laser ◽  
Lattice Parameter ◽  
Laser Deposition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Deposited Films ◽  
Post Deposition

AbstractThe effect of a post deposition anneal on the structure and dielectric properties of epitaxial Sr1−x, BaxTiO3 (SBT) thin films with x = 0.35, 0.50 and 0.60 has been measured. The films were grown by pulsed laser deposition on LaAlO3(001) substrates at 750°C in 350 mTorr of oxygen. The asdeposited films were single phase, (001) oriented with 0)-scan widths for the (002) reflection between 0.160 and 0.50'. The dielectric properties of the as-deposited films exhibit a broad temperature dependence and a peak which is as much as 50 K below the peak in bulk SBT. Also, the lattice parameter, as measured by x-ray diffraction, of the as-deposited films was larger than the bulk indicating strain in the films. The as-deposited films were annealed for 8 hours at 900°C in oxygen. The dielectric properties of the annealed films were closer to that of bulk SBT and the lattice parameter was closer to the bulk lattice parameter indicating a reduction of strain. Annealing of as-deposited films also resulted in an increased dielectric tuning without increased dielectric loss.

La-Doped CaCu3Ti4O12 Ceramics Sintered in Argon Environment

2010 ◽  
Vol 173 ◽  
pp. 167-172
Author(s):  
N. Shafiza Afzan Sharif ◽  
Sabar Derita Hutagalung ◽  
Zainal A. Ahmad
Keyword(s):  
Single Phase ◽  
Xrd Analysis ◽  
Lattice Parameter ◽  
Lattice Expansion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Group A ◽  
Cubic Structure ◽  
A Minor ◽  
La Doped

The properties of undoped and La-doped CaCu3Ti4O12 ceramics synthesized via solid state reaction under argon environment had been studied. It was found that La-doped CCTOs gave higher dielectric constant and lower dielectric loss than undoped CCTO. X-ray diffraction (XRD) analysis indicated that all of the sintered samples have single-phase cubic structure (space group ). A minor shifted was observed in the peak positions for La-doped samples, which are attributed to the lattice expansion. The lattice parameter obtained from XRD analysis is 7.348 Å for undoped CCTO and increases to 7.348 – 7.377 Å for La-doped CCTOs. The results proven that La ions have effectively substituted into the Ca site of CCTO.

Search for New Semiconductors for High Temperature Applications:The BaPb1-x BixO3 System

1998 ◽  
Vol 512 ◽  
Author(s):  
V. Ponnambalam ◽  
U. V. Varadaraju
Keyword(s):  
Phase Transition ◽  
High Temperature ◽  
Single Phase ◽  
Random Distribution ◽  
Lattice Parameter ◽  
Cubic Phase ◽  
Linear Variation ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Power Factor

ABSTRACTBaPbl-xBixO3 phases with 0.6⋚ x⋚ 1.0 were synthesized by high temperature solid state reaction. Powder X-ray diffraction measurements show that all compositions are in single phase. Linear variation of lattice parameter is observed in BaPb1-xBixO3 with change in x indicating the random distribution of Pb in Bi sites. The activation energies for conduction of phases with x=0.8−0.6 obtained from ρ −T plots are same suggesting that the band gap does not change for compositions with x-0.8−0.6. The low activation energy obtained for BaBiO3 can be attributed to the structure of the compound. S versus (1000/T) data of x=1.0−0.8 exhibit a two-slope behavior. The orthorhombic to cubic phase transition could be the possible reason for the high power factor values of BaBiO3.

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