Nanostructured TiO2-Based Composites for Light Absorption

2014 ◽  
Vol 975 ◽  
pp. 207-212
Author(s):  
Dayse I. dos Santos ◽  
Olayr Modesto Jr. ◽  
Luis Vicente A. Scalvi ◽  
Americo S. Tabata
Keyword(s):  
Metal Oxide ◽  
Light Absorption ◽  
Structural Characteristics ◽  
Sol Gel ◽  
Second Phase ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Oxide Powders

Metal oxide nanocomposites were prepared by two different routes: polyol and sol-gel. Characterization by X ray diffraction showed that the first process produces directly a two-phase material, while the sol-gel powder never showed second phase below 600°C. Light spectroscopy of the treated powders indicated similarities for the processed materials. Although the overall material compositions are about the same, different structural characteristics are found for each processing. With the exception of Ti-Zn materials, all the double metal oxide powders showed higher absorbance than either TiO2 powder.

High Curie temperature perovskite BiInO3–PbTiO3 ceramics

2004 ◽  
Vol 19 (7) ◽  
pp. 2185-2193 ◽  
Author(s):  
Runrun Duan ◽  
Robert F. Speyer ◽  
Edward Alberta ◽  
Thomas R. Shrout
Keyword(s):  
Curie Temperature ◽  
Sol Gel ◽  
High Curie Temperature ◽  
Dielectric Measurements ◽  
X Ray Diffraction ◽  
Compound Formation ◽  
X Ray ◽  
Oxide Powders ◽  
Phase Pure ◽  
Pbtio3 Ceramics

The extent of BiInO3 substitution in the perovskite system xBiInO3–(1 - x)PbTiO3 and the corresponding raise in the Curie temperature were investigated using thermal analysis, dielectric measurements, x-ray diffraction, and electron microscopy. Maximum tetragonal perovskite distortion (c/a = 1.082) was obtained for x = 0.20, with a corresponding Curie temperature of 582 °C. Phase-pure tetragonal perovskite was obtained for x ⩽ 0.25. Compound formation after calcining mixed oxide powders resulted in agglomerated cube-shaped tetragonal perovskite particles, which could be fired to 94.7% of theoretical density (TD). Sol-gel fabrication resulted in nano-sized tetragonal or pseudo-cubic perovskite particles, which after two-step firing, resulted in a tetragonal perovskite microstructure at as high as (x = 0.20) 98.1% of TD.

On the Formation of Martensite in In0.77TL0.23.

1990 ◽  
Vol 205 ◽  
Author(s):  
M. Wuttig ◽  
X. Zhou ◽  
S. Nahm ◽  
J. Li
Keyword(s):  
Transformation Temperature ◽  
Mechanical Response ◽  
High Temperature Phase ◽  
Second Phase ◽  
Temperature Phase ◽  
Product Phase ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Precursor Structure

AbstractIt has been proposed that martensite is formed by heterogeneous nucleation and growth or evolves from a precursor. In order to examine these theories, high resolution X-ray diffraction experiments have been performed on In0.77Tl0.23. It is known that the transformation of the alloy is close to second order and tweed has been observed which could be a possible precursor structure. Our experimental results do show precursors but of a different nature: satellites around the 220 Bragg peak have been detected up to 15 degrees above the transformation temperature. They develop reversibly at the angular positions of the product phase. The results are not compatible with the “crest-riding-peridon” model but rather show an equilibrium two phase mixture above the transformation temperature in which the second phase is structurally equal to the product phase. We have also investigated the mechanical response of the high temperature phase and found that both shear ‘elastic constants’ soften. This result can be understood in terms of twin boundary or stacking fault motion.

Structural, Magnetic and Microwave Absorbing Properties of Nanosized NiXZn1-xFe2O4 Powders Synthesized by Sol-Gel Technique

2010 ◽  
Vol 148-149 ◽  
pp. 1144-1147
Author(s):  
Xiang Rong Zhu ◽  
Lin Feng Lu ◽  
Hong Lie Shen
Keyword(s):  
Room Temperature ◽  
Structural Characteristics ◽  
Sol Gel ◽  
Frequency Range ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Gel Technique ◽  
Soft Magnetism

NixZn1-xFe2O4 (x=0.4, 0.6) powders are synthesized by sol-gel technique. The X-ray diffraction (XRD) measurements show their polycrystalline spinel structural characteristics. Both XRD and Atomic Force Microscopy demonstrate the samples are nanosized. At room temperature typical soft magnetism is exhibited by the samples. The reflection attenuation resulting from microwave absorption would reach to 1.9 dBm over the frequency range 6 GHz - 10 GHz when the samples are paved on a 10 cm  10 cm square aluminum plate with a thickness of about 0.35 mm.

Preparation and Dielectric Properties of La Doped Bi2Al4O9

2013 ◽  
Vol 423-426 ◽  
pp. 890-893
Author(s):  
Xiao Yan Zhang ◽  
Xi Wei Qi ◽  
Jun Fang Wei ◽  
Wen Shu Hu ◽  
Gui Fang Sun ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Dielectric Properties ◽  
Sol Gel ◽  
Frequency Stability ◽  
Second Phase ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
La Doped ◽  
Scanning Electron

A series of (Bi1-xLax)2Al4O9(x = 0, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.40) ceramics were prepared by sol-gel method with sintering process. Doping dependent investigations were carried out to show the influence of La atom on the structural stability. The products were characterized using X-ray diffraction, scanning electron microscopy. This showed that the second phase is increased gradually by La doping. When the value of La is 0.4, the main phase tends to become LaAlO3. Details on dielectric properties are reported. The permittivity of as-prepared doped samples increases slightly compared to pure Bi2Al4O9and excellent frequency stability is exhibited.

Synthesis and Characterization of Bi2Al4O9 Powders

2012 ◽  
Vol 624 ◽  
pp. 34-37
Author(s):  
Xiao Yan Zhang ◽  
Wen Shu Hu ◽  
Xi Wei Qi ◽  
Gui Fang Sun ◽  
Jian Quan Qi ◽  
...  
Keyword(s):  
Crystallization Process ◽  
Sol Gel ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Absorption Bands ◽  
X Ray ◽  
Oxide Powders ◽  
Sol Gel Process ◽  
Ft Ir

Bi2Al4O9 powders were prepared by sol-gel process. The precursors were heated at 500-800°C for 2h to obtain Bi2Al4O9 powder and X-ray diffraction (XRD), Differential thermal analysis (DTA), thermogravimetric analysis (TG), field emission scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR) techniques were used to characterize precursor and derived oxide powders. XRD analysis show that the powder is still amorphous after calcined at 500°C. The peaks of Bi2Al4O9 become sharp after calcined at 575°C though still existing some amorphous phase. After calcining at 675-800°C, the powder has fully turned into pure Bi2Al4O9 phase. The crystallization process can also be confirmed by DTA-TG and IR. Calcining the precursor at 575°C, the absorption bands at 527 cm-1, 738 cm-1, 777 cm-1, and 919 cm-1are observed, which are assigned to Bi2Al4O9 and becoming stronger and sharper with the increase of temperature.

scholarly journals Structural Characteristics of Bimetallic Catalysts Supported on Nano-Ceria

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
J. F. Bozeman ◽  
H. Huang
Keyword(s):  
Solid Oxide Fuel Cells ◽  
Structural Characteristics ◽  
Low Cost ◽  
Sol Gel ◽  
Average Particle Size ◽  
Fluorite Structure ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nano Ceria

Cu-Pt bimetal catalysts supported on nanocrystalline CeO2(nano-ceria) are synthesized via the low-cost sol-gel approach followed by impregnation processing. The average particle size of the catalytic composites is 63 nm. Ceria nanopowders sequentially impregnated in copper solution and then in Pt solution transformed into Pt-skin-structured Cu-Pt/ceria nanocomposite, based on the surface elemental and bulk compositional analyses. The ceria supporter has a fluorite structure, but the structure of Cu and Pt catalytic contents, not detected by X-ray diffraction spectroscopy due to the low loading level, is yet conclusive. The bimetallic catalytic nanocomposites may potentially serve as sulfur-tolerant anode in solid oxide fuel cells.

Lower crystallization temperature of sol-gel PbTiO3 on Ti/Pt-coated substrates

1999 ◽  
Vol 14 (6) ◽  
pp. 2369-2372 ◽  
Author(s):  
R. E. Avila ◽  
T. P. Velilla ◽  
P. J. Retuert
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Refractive Index ◽  
Sintering Temperature ◽  
Perovskite Phase ◽  
Sol Gel ◽  
Second Phase ◽  
X Ray Diffraction ◽  
Range Analysis ◽  
X Ray

PbTiO3 (PT) thin films have been deposited by sol-gel on Pt/Si, SiO2/Si, Pt/Ti/SiO2/Si, and Ti/Pt/Ti/SiO2/Si and annealed for 45 min in the 400–670 °C range. Analysis by x-ray diffraction (XRD) and spectroscopic ellipsometry shows that the Ti overlayer promotes early crystallization in the tetragonal perovskite phase, reducing the presence of a second phase, tentatively identified as pyrochlore, starting by 450 %C. The refractive index and extinction coefficient (n, k) of the PT film increase rapidly with the sintering temperature in the range of 450–570 °C and saturate by 570 °C to values of n varying from 2.4 to 2.9, and k from 0.03 to 0.3, over the 1.65–2.95 eV range. Most of the increase of n is related to thin film densification.

A High Resolution Study of G.P. Zones in Aluminum - 4.2 at % Silver

1982 ◽  
Vol 40 ◽  
pp. 722-723 ◽  
Author(s):  
R. Gronsky
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Computer Simulations ◽  
Structural Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Resolution Study

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.

PENGGUNAAN TiO2 PARTIKEL NANO HASIL SINTESIS BERBASIS AIR MENGGUNAKAN METODA SOL-GEL PADA BAHAN KAPAS SEBAGAI APLIKASI UNTUK TEKSTIL ANTI UV

Arena Tekstil ◽  
2013 ◽  
Vol 28 (1) ◽  
Author(s):  
Maya Komalasari ◽  
Bambang Sunendar
Keyword(s):  
Fourier Transform ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Sol Gel ◽  
Crosslinking Agent ◽  
X Ray Diffraction ◽  
Nano Tio2 ◽  
X Ray ◽  
Infra Red ◽  
Scanning Electron

Partikel nano TiO2 berbasis air dengan pH basa telah berhasil disintesis dengan menggunakan metode sol-gel dan diimobilisasi pada kain kapas dengan menggunakan kitosan sebagai zat pengikat silang. Sintesis dilakukan  dengan prekursor TiCl4 pada konsentrasi 0,3 M, 0,5 M dan 1 M, dan menggunakan templat kanji dengan proses kalsinasi pada suhu 500˚C selama 2 jam. Partikel nano TiO2 diaplikasikan ke kain kapas dengan metoda pad-dry-cure dan menggunakan kitosan sebagai crosslinking agent. Berdasarkan hasil Scanning Electron Microscope (SEM),diketahui bahwa morfologi partikel TiO2 berbentuk spherical dengan ukuran nano (kurang dari 100 nm). Karakterisasi X-Ray Diffraction (XRD) menunjukkan adanya tiga tipe struktur kristal utama, yaitu (100), (101) dan (102) dengan fasa kristal yang terbentuk adalah anatase dan rutile. Pada karakterisasi menggunakan SEM terhadap serbuk dari TiO2 yang telah diaplikasikan ke permukaan kain kapas, terlihat adanya imobilisasi partikel nano TiO2 melalui ikatan hidrogen silang dengan kitosan pada kain kapas. Hasil analisa tersebut kemudian dikonfirmasi dengan FTIR (Fourier Transform Infra Red) yang hasilnya memperlihatkan puncak serapan pada bilangan gelombang 3495 cm-1, 2546 cm-1, dan 511 cm-1,  yang masing-masing diasumsikan sebagai adanya vibrasi gugus fungsi O-H, N-H dan Ti-O-Ti. Hasil SEM menunjukkan pula bahwa kristal nano yang terbentuk diantaranya adalah fasa rutile , yang berdasarkan literatur terbukti dapatberfungsi sebagai anti UV.

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