Structural characterization of TiO2 ultrafine particles

1999 ◽  
Vol 14 (2) ◽  
pp. 442-446 ◽  
Author(s):  
Yingchun Zhu ◽  
Tiao Liu ◽  
Chuanxian Ding
Keyword(s):  
Crystal Structure ◽  
Raman Spectroscopy ◽  
Phase Transformation ◽  
Fourier Transform ◽  
Raman Spectra ◽  
Ultrafine Particles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Factors Influencing

Four samples of TiO2 ultrafine particles (UFP) were obtained through different processes. The structure of TiO2 ultrafine particles and the factors influencing the structure were investigated with Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and x-ray diffraction (XRD). Both Raman spectra and x-ray diffractograms show the similar regularity of the phase transformation among the four samples. The observed bimodal lineshape-structure in the Raman spectra is attributed to the intragrain and grain-boundary components of TiO2 UFP. The crystal structure of TiO2 UFP is found to be distorted by the surface structure such as OH and OCH2CH3 groups coordinated on the surface of TiO2 UFP.

Structure of Oxides Grown on Zr-20Nb Alloy

1994 ◽  
Vol 357 ◽  
Author(s):  
O.T. Woo ◽  
D.J. Lockwood ◽  
Y.P. Lin ◽  
V.F. Urbanic
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Raman Spectroscopy ◽  
Raman Spectra ◽  
High Symmetry ◽  
X Ray Diffraction ◽  
Short Term ◽  
X Ray ◽  
Transmission Electron

AbstractOxides grown on Zr-20Nb were characterized by Raman Spectroscopy (RS), X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). These oxides were steamformed at 400°C, water-formed at 360 °C and at 300 °C, and air-grown at 400°C. For the oxides grown after relatively short exposures at 360°C and at 400°C, Raman spectra revealed broad peaks at 260 and 660 cm− indicating a crystal structure with high symmetry. Comparison with reference Raman spectra of cubic (c), tetragonal (t), and monoclinic (m) ZrO2 suggested that the oxide was predominantly nearly-cubic (tetragonal with c/a ratio ≈ 1), with minor amounts of moxide. The tetragonality is found to be consistent with TEM analyses and XRD results which showed the presence of a doublet near 2θ ° 74°. The crystal structure in the short-term exposed oxides is interpreted in terms of a tetragonal distortion arising from the displacement of oxygen atoms within the cubic ZrO2 crystal structure. For oxides grown after longer periods of exposure at 300°C and at 400°C, RS and XRD indicate increased amounts of m-oxide.

RAMAN SCATTERING AND X-RAY DIFFRACTION CHARACTERIZATION OF AMORPHOUS SEMICONDUCTOR MULTILAYER INTERFACES

1985 ◽  
Vol 56 ◽  
Author(s):  
J. GONZALEZ ◽  
D.D. ALLRED ◽  
O.V. NGUYEN ◽  
D. MARTIN ◽  
D. PAWLIK
Keyword(s):  
Raman Spectroscopy ◽  
Raman Scattering ◽  
Raman Spectra ◽  
Amorphous Semiconductor ◽  
Chemical Bonds ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sharp Interfaces ◽  
Deposition Techniques

AbstractIn the present study, Raman spectroscopy (RS) and x-ray diffraction have been used to characterize semiconductor multilayer interfaces. A model for Raman spectra of multilayers is developed and applied to the specific case of the interfaces of a-Si/a-Ge multilayers. Quantification of the ‘blurring’ of interfaces is possible because RS is capable of directly ‘counting’ the total number of chemical bonds of a given type in the film. Multilayers, prepared by various deposition techniques, are compared. Several a-Si/a-Ge multilayers deposited by UHV evaporation (MBD) exhibit exceptionally sharp interfaces (intermixing width <l.0Å) and regular periodicities.

CHARACTERIZATION OF POTASSIUM DOPED GdBa2Cu3O7−δ USING RAMAN SPECTROSCOPY AND X-RAY DIFFRACTION

1995 ◽  
Vol 09 (26n27) ◽  
pp. 1739-1752
Author(s):  
PREETHI CICILY THOMAS ◽  
MANOJ KUMAR K. ◽  
V. UNNIKRISHNAN NAYAR ◽  
VIDYALAL V. ◽  
C.P.G. VALLABHAN
Keyword(s):  
Raman Spectroscopy ◽  
Raman Spectra ◽  
Tetragonal Phase ◽  
Orthorhombic Phase ◽  
Superconducting Transition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Resistivity Measurements ◽  
Xrd Patterns

Potassium doped and undoped GdBa 2 Cu 3 O 7−δ have been prepared and superconducting transition temperatures between 92 K and 100 K have been determined from resistivity measurements. Raman spectra of doped and undoped samples are identical and they contain bands corresponding to both the superconducting orthorhombic phase and nonsuperconducting tetragonal phase. XRD patterns also reveal both the phases. Raman spectra recorded at 92 K of undoped GdBa 2 Cu 3 O 7−δ and doped GdBa 2 Cu 3 O 7−δ with weight percentages 0.75, 1.00, 1.25 and 1.50 of K shows a softening of the band at 338 cm−1.

Deposition of TRISO Particles With Superhard SiC Coatings and the Characterization of Anisotropy by Raman Spectroscopy

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
E. López-Honorato ◽  
P. J. Meadows ◽  
J. Tan ◽  
Y. Xiang ◽  
P. Xiao
Keyword(s):  
Solid Solution ◽  
Raman Spectroscopy ◽  
Pyrolytic Carbon ◽  
X Ray Diffraction ◽  
X Ray ◽  
Flat Substrate ◽  
High Concentrations ◽  
Triso Particles ◽  
Sic Coatings

In this work we have deposited silicon carbide (SiC) at 1300°C with the addition of small amounts of propylene. The use of propylene and high concentrations of methyltrichlorosilane (9 vol %) allowed the deposition of superhard SiC coatings (42 GPa). The superhard SiC could result from the presence of a SiC–C solid solution, undetectable by X-ray diffraction but visible by Raman spectroscopy. Another sample obtained by the use of 50 vol % Argon, also showed the formation of SiC with good properties. The use of a flat substrate together with the particles showed the importance of carrying out the analysis on actual particles rather than in flat substrates. We show that it is possible to characterize the anisotropy of pyrolytic carbon by Raman spectroscopy.

scholarly journals Synthesis and Structural Properties of Nanocomposites Based on Synthetic Opals and Active Dielectrics

2019 ◽  
Vol 12 (1) ◽  
pp. 19
Author(s):  
Bilal Abu Sal
Keyword(s):  
Raman Spectroscopy ◽  
Single Crystals ◽  
Structural Properties ◽  
Raman Spectra ◽  
Phase Structure ◽  
Opal Matrix ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystal State ◽  
Synthetic Opals

This work is devoted to generalize and analyze the previouse results of new photonic-crystalline nanomaterials based on synthetic opals and active dielectrics. Data were characterized by X-ray diffraction and Raman spectroscopy. Active dielectrics infiltrated into the pores of the opal from the melt. The phase structure composition of the infiltrated materials into the pores of the opal matrix were analyzed. The results of x-ray diffraction and Raman spectra allowed to establish the crystal state of active dielectrics in the pores of the opal. The Raman spectra of some opal-active dielectric nanocomposites revealed new bands and changes in band intensities compared to the spectra of single crystals of active dielectrics. Further more, differences in band intensities in the spectra were measured at different spots of the sample&lsquo;s surface were observed. The revealed changes were attributed to the formation of new crystalline phases due to the injected dielectrics in opal pores.

scholarly journals Serendipitous formation and characterization of K2[Pd(NO3)4]·2HNO3

2019 ◽  
Vol 74 (4) ◽  
pp. 381-387
Author(s):  
Michael Zoller ◽  
Jörn Bruns ◽  
Gunter Heymann ◽  
Klaus Wurst ◽  
Hubert Huppertz
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Monoclinic Space Group ◽  
Solvothermal Process ◽  
X Ray Diffraction ◽  
Glass Ampoule ◽  
Space Group ◽  
X Ray ◽  
Complex Anions

AbstractA potassium tetranitratopalladate(II) with the composition K2[Pd(NO3)4] · 2HNO3 was synthesized by a simple solvothermal process in a glass ampoule. The new compound crystallizes in the monoclinic space group P21/c (no. 14) with the lattice parameters a = 1017.15(4), b = 892.94(3), c = 880.55(3) Å, and β = 98.13(1)° (Z = 2). The crystal structure of K2[Pd(NO3)4] · 2HNO3 reveals isolated complex [Pd(NO3)4]2− anions, which are surrounded by eight potassium cations and four HNO3 molecules. The complex anions and the cations are associated in layers which are separated by HNO3 molecules. K2[Pd(NO3)4] · 2HNO3 can thus be regarded as a HNO3 intercalation variant of β-K2[Pd(NO3)4]. The characterization is based on single-crystal X-ray and powder X-ray diffraction.

Crystal structure, thermodynamic properties and detonation characterization of bis(5-amino-1,2,4-triazol-3-yl)methane

2020 ◽  
Vol 76 (1) ◽  
pp. 64-68 ◽  
Author(s):  
Hongya Li ◽  
Biao Yan ◽  
Haixia Ma ◽  
Zhiyong Sun ◽  
Yajun Ma ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Detonation Velocity ◽  
Theoretical Calculations ◽  
Detonation Pressure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Equivalent Equation ◽  
Experimental Values ◽  
Experimental Density

Bis(5-amino-1,2,4-triazol-3-yl)methane (BATZM, C5H8N8) was synthesized and its crystal structure characterized by single-crystal X-ray diffraction; it belongs to the space group Fdd2 (orthorhombic) with Z = 8. The structure of BATZM can be described as a V-shaped molecule with reasonable chemical geometry and no disorder. The specific molar heat capacity (Cp,m ) of BATZM was determined using the continuous Cp mode of a microcalorimeter and theoretical calculations, and the Cp,m value is 211.19 J K−1 mol−1 at 298.15 K. The relative deviations between the theoretical and experimental values of Cp,m , HT – H 298.15K and ST – S 298.15K of BATZM are almost equivalent at each temperature. The detonation velocity (D) and detonation pressure (P) of BATZM were estimated using the nitrogen equivalent equation according to the experimental density; BATZM has a higher detonation velocity (7954.87 ± 3.29 m s−1) and detonation pressure (25.72 ± 0.03 GPa) than TNT.

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