Crystallization Behavior of Chemically Prepared and Rapidly Solidified PbTiO3

1988 ◽  
Vol 121 ◽  
Author(s):  
Robert W. Schwartz ◽  
D. A. Payne
Keyword(s):  
Crystallization Behavior ◽  
Fine Particles ◽  
Sol Gel ◽  
Free Energies ◽  
X Ray Diffraction ◽  
Surface Areas ◽  
Treatment Conditions ◽  
Polymeric Sol ◽  
Co Precipitation ◽  
Rapidly Solidified

ABSTRACTThe crystallization behavior of chemically prepared and rapidly solidified PbTiO3 was investigated. Chemical methods were (i) polymeric sol-gel processing and (ii) co-precipitation of fine particles. Rapid solidification was obtained by a twin-roller quencher. Details are reported for the processing methods and the characteristics of the materials. X-ray diffraction and electron microscopy confirmed the amorphous nature of the prepared materials. Crystallization was examined as a function of heat-treatment conditions. Non-isothermal DSC was used to determine the kinetics of crystallization. Activation energies and frequency factors were determined. Co-precipitated PbTiO3 crystallized at the lowest temperature of 375 C, followed by sol-gel at 425 C, and rapidly solidified at 475 C. The results are interpreted in terms of processing routes, structural free-energies, available surface areas and fractional free volumes.

Effect of Iron (III)-Doping on the Photocatalytic Activity of Titanium Dioxide Catalysts for Methylene Blue Degradation

2011 ◽  
Vol 117-119 ◽  
pp. 1088-1091
Author(s):  
Wen Churng Lin ◽  
Rui Liu ◽  
Wein Duo Yang
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Specific Surface ◽  
Effective Means ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Surface Areas ◽  
Bet Specific Surface Area ◽  
Vis Spectroscopy

Iron-doped TiO2 photocatalyst powders were prepared by the sol–gel method and characterized by Brunauer–Emmett–Teller (BET)-specific surface area, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Ultraviolet–Visible (UV-Vis) spectroscopy. Fe3+ doping in the TiO2 decreases the crystal grain size, increases the specific surface areas of powders, extends the absorption to visible light regions (400~500 nm), and lowers the photocatalytic activity for methylene blue (MB) degradation under UV irradiation. The photocatalytic degradation of MB in water was investigated as a function of the Fe3+ content in TiO2. It was found that under the irradiation of visible light, a small amount of Fe3+ dopant in TiO22 powders could obviously enhance the photocatalytic activity. When the Fe3+ content was in the range of 0.03–0.1 mol%, the photocatalytic activity of the samples was higher than that of undoped TiO2. Appropriate content of Fe-doping is an effective means to improve the photocatalytic activity of TiO2 for MB degradation under visible light irradiation.

Synthesis and Photocatalytic Properties of ZnO-Volcanics Composites

2013 ◽  
Vol 331 ◽  
pp. 497-502
Author(s):  
Ai Hua Wang ◽  
Ping Che ◽  
Jie Min Liu ◽  
Gui Hua Wang
Keyword(s):  
Calcination Temperature ◽  
Physical Adsorption ◽  
Sol Gel ◽  
Degradation Efficiency ◽  
X Ray Diffraction ◽  
Photocatalytic Reactor ◽  
Decolorization Rate ◽  
Surface Areas ◽  
Transmission Electron ◽  
Average Grain Size

in this paper, nano-ZnO were synthesized via a sol-gel method, and ZnO-volcanics composites (ZVCs) were prepared via physical adsorption process. The morphology and structure of ZnO/ ZnO-volcanics composites (ZVCs) samples were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM).BET surface areas of the catalysts were determined by N2 adsorption (BET). According the data of XRD, the average grain size of ZnO is 15.1 nm consistent with the result observed by TEM (16.3 nm). Photocatalytic performance of ZnO and ZVCs were carried out in sprinkling photocatalytic reactor, with methylene blue (MB) as pollutants model. Decolorization rate is select as the evaluation parameters for the degradation effect. The effect of catalyst dosage, MB initial concentration, calcination temperature and pH on the degradation efficiency have been investigated. The MB degradation efficiency was 99.2% when the concentration of MB, the ZVCs, the pH and the calcination temperature were 10 mg/L, 20 g/L, and 10.03, 500 oC respectively. In the catalysts recycle experiments, the decolorization rate of MB using ZVCs is 90.2% after utilization for six times, overwhelmingly higher than that of ZnO (22.6%), indicating immobilization is efficient.

Effects of Calcination Parameters on the Microstructure and Morphology of PZT Nanoparticles Prepared by Modified Sol–Gel Method

2012 ◽  
Vol 576 ◽  
pp. 326-329 ◽  
Author(s):  
Amid Shakeri ◽  
Hossein Abdizadeh ◽  
Mohammad Reza Golobostanfard
Keyword(s):  
Lead Zirconate Titanate ◽  
Sol Gel ◽  
Lead Zirconate ◽  
X Ray Diffraction ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Treatment Conditions ◽  
Perovskite Type ◽  
Perovskite Type Structure

Lead zirconate titanate nanopowder Pb(Zr0.53Ti0.47)O3 (PZT) was prepared by modified sol-gel method with 1-propanol as solvent and acetylacetone as stabilizer. The microstructure and particle size measurements at different heat treatment conditions were characterized by field emission scanning electron microscopy and x-ray diffraction analysis. It was found that the PZT nanoparticles calcinated at 600 °C showed mean diameter of 75-125 nm with high crystallinity of perovskite-type structure.

MgO-Al2O3-SiO2 Glass-Ceramic Prepared by Sol-Gel Method

2010 ◽  
Vol 92 ◽  
pp. 131-137 ◽  
Author(s):  
Qiu Hua Yuan ◽  
Pei Xin Zhang ◽  
Li Gao ◽  
Hai Lin Peng ◽  
Xiang Zhong Ren ◽  
...  
Keyword(s):  
Glass Ceramic ◽  
Crystallization Behavior ◽  
Glass Powder ◽  
Sol Gel ◽  
Glass Ceramics ◽  
Green Body ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
Sio2 Glass ◽  
X Ray

The crystallization behavior of MgO-Al2O3-SiO2 glass-ceramics by sol-gel technology was investigated by using x-ray diffraction (XRD), differential thermal analysis (DTA), Scanning electron microscopy (SEM). The results showed that: (1)α-cordierite phase was precipitated when the green body was calcined at 1050°C, and α-cordierite of high purity and stability could be formed at 1100°C; (2) Adding an appropriate amount of low melting point glass powder into the green body may provide liquid-phase environment during the sintering process, which will help enhance the tightness density of glass-ceramic, and thus improve its flexural strength.

The Process of Sol-Gel Method Prepared Bi-2212 Superconductors Tapes

2013 ◽  
Vol 275-277 ◽  
pp. 2300-2303
Author(s):  
Gen Zong Song ◽  
Duo Zhang
Keyword(s):  
Heat Treatment ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Ni Substrate ◽  
Treatment Conditions ◽  
Drying Conditions ◽  
And Control

In this dissertation, Bi-2212 superconducting tapes was prepared by sol-gel method, in addition we mainly studied heat treatment conditions and sintering material drying conditions of the NiO/Ni substrate, and gived a optimization to the process. The heat treatment process of the NiO/Ni substrate had been researched.Based on previous experience, we explored the temperature of heat treatment and improved the process.Afterheattreatment,the samples was analyzed by metallographic microscope and X-ray diffraction,and we analysed these data. It’s concluded that the dense uniform oxide film can be sintered in 800°C with a 3 hours’ heat treatment.We further explored the conditions of the Bi-2212 superconducting materials.During the preparation. We mainly studied the drying temperature and sintering temperature ,because they would affect the gel phase transition and control components. It has a very important effect on high-quality superconducting strip preparation. Experiments results showed that drying the sample at 510 °C in temperature is best. all the samples was analyzed by X-ray diffraction. We summed up the data derived from experiments , it showed that sintering the sample at 850°C,we can obtain the mixed phase of Bi-2201 and Bi-2212.

scholarly journals MXene/Ag2CrO4 Nanocomposite as Supercapacitors Electrode

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6008
Author(s):  
Tahira Yaqoob ◽  
Malika Rani ◽  
Arshad Mahmood ◽  
Rubia Shafique ◽  
Safia Khan ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Low Cost ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Energy Storage Devices ◽  
X Ray ◽  
Storage Devices ◽  
Bonding Structure ◽  
Electron Transfer Rate Constant ◽  
Co Precipitation

MXene/Ag2CrO4 nanocomposite was synthesized effectively by means of superficial low-cost co-precipitation technique in order to inspect its capacitive storage potential for supercapacitors. MXene was etched from MAX powder and Ag2CrO4 spinel was synthesized by an easy sol-gel scheme. X-Ray diffraction (XRD) revealed an addition in inter-planar spacing from 4.7 Å to 6.2 Å while Ag2CrO4 nanoparticles diffused in form of clusters over MXene layers that had been explored by scanning electron microscopy (SEM). Energy dispersive X-Ray (EDX) demonstrated the elemental analysis. Raman spectroscopy opens the gap between bonding structure of as-synthesized nanocomposite. From photoluminence (PL) spectra the energy band gap value 3.86 eV was estimated. Electrode properties were characterized by applying electrochemical observations such as cyclic voltammetry along with electrochemical impedance spectroscopy (EIS) for understanding redox mechanism and electron transfer rate constant Kapp. Additionally, this novel work will be an assessment to analyze the capacitive behavior of electrode in different electrolytes such as in acidic of 0.1 M H2SO4 has specific capacitance Csp = 525 F/g at 10 mVs−1 and much low value in basic of 1 M KOH electrolyte. This paper reflects the novel synthesis and applications of MXene/Ag2CrO4 nanocomposite electrode fabrication in energy storage devices such as supercapacitors.

Crystallization Kinetics of Li+-Doped TiO2 Films Prepared by Sol-Gel Dip Coating

2010 ◽  
Vol 105-106 ◽  
pp. 750-753
Author(s):  
Feng Zhou ◽  
Ying Qing Fu ◽  
Kai Ming Liang
Keyword(s):  
Crystallization Behavior ◽  
Tio2 Thin Film ◽  
Sol Gel ◽  
Dip Coating ◽  
X Ray Diffraction ◽  
Tio2 Thin Films ◽  
Doped Tio2 ◽  
X Ray ◽  
Li Ion ◽  
Kinetics Of

The crystallization behavior and microstructure of Li+-doped TiO2 thin films prepared by sol-gel dip coating were investigated by means of differential themal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The crystallization apparent activation energy (E) both in the absence and in the presence of Li+ ion was also measured with Kissinger method. As a result the E values of Li+-doped TiO2 thin film were decreased, thus the crystallization of non-crystalline to anatase and antase to rutile was promoted.

Synthesis of Y0.2ZrXCe0.8−XO1.9 Electrolytes From the Sol-Gel Method for Intermediate Temperature URSOFC Application

2012 ◽  
Vol 9 (4) ◽  
Author(s):  
Guo-Bin Jung ◽  
Ting-Chu Jao ◽  
Chia-Chen Yeh ◽  
Ming-Hsien Huang ◽  
Wang-Shen Su
Keyword(s):  
Solid Oxide Fuel Cells ◽  
Relative Density ◽  
Sol Gel ◽  
Thermo Gravimetric Analysis ◽  
Intermediate Temperature ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Gel Method ◽  
Sol Gel Method ◽  
Co Precipitation

A series of Y0.2ZrxCe0.8−xO1.9 compounds (0 ≤ x ≤ 0.6) had been prepared by the modified sol-gel method and characterized by powder X-ray diffraction, thermo-gravimetric analysis, four-probe resistivity, and Vickers’s hardness studies. The gels from co-precipitation were treated with heated 1-octanol. All of the samples showed fluoride structure after calcined at 600 °C. Sintering the powders of Y0.2Ce0.8O1.9 and Y0.2Zr0.6Ce0.2O1.9 at 1300 °C gave the relative density of 95.8% and 99%, respectively. 99% relative density could be obtained for all samples after sintering at 1500 °C. This study showed a much more improved result than that of the previous reports. The hardness was 13.7 GPa for the Y0.2Zr0.6Ce0.2O1.9 pellet, which was twice greater than that for Y0.2Ce0.8O1.9 (7.1 GPa). Therefore, the mechanical properties could be improved by the addition of ZrO2 to Y0.2ZrxCe0.8−xO1.9. At 800 °C, the electrical conductivity of Y0.2Ce0.8O1.9 and Y0.2Zr0.6Ce0.2O1.9 were 3.3 × 10−2 S/cm and 5.5 × 10−3 S/cm, respectively. The conductivity was decreased by the addition of ZrO2 to Y0.2Ce0.8O1.9. It showed that the conductivity and hardness of Y0.2Zr0.2Ce0.6O1.9 were 1.2 × 10−2 S/cm and 9.6 GPa, respectively, at 800 °C and could be a better electrolyte candidate for “intermediate-temperature” unitized regenerative solid oxide fuel cells.

Influence of Heat Treatment on the Structure and Performance of ATP and its Catalyzer

2011 ◽  
Vol 295-297 ◽  
pp. 1510-1515 ◽  
Author(s):  
Yue Bin Lin ◽  
Chun Bo Li ◽  
Yu Fu Zhu ◽  
Ai Hui Liu
Keyword(s):  
Heat Treatment ◽  
Thermal Analysis ◽  
Spectroscopic Analysis ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Treatment Conditions ◽  
Transmission Electron ◽  
Crystal Transition ◽  
And Performance

Taking Attapulgite Clay(ATP) as a carrier, TiO2/ATP precursor was prepared by acid sol-gel method, and then made its composite under different heat-treatment conditions. The structures, dimensions, compositions of the composite are characterized by X-Ray diffraction, transmission electron microscope, thermogravimetric-differential thermal analysis and spectroscopic analysis measurements, respectively. the results show that TiO2/ATP composite increase the crystal transition temperature of TiO2, rutile TiO2emerge in the composite until 800°C, ATP lost its layer constructure and collapse at 850°C.

Study of Preparation, Characterization and Temperature-Programmed Reduction of NiO-ZnO Binary Materials

2013 ◽  
Vol 664 ◽  
pp. 515-520
Author(s):  
Chih Wei Tang ◽  
Jiunn Jer Hwang ◽  
Shie Hsiung Lin ◽  
Chin Chun Chung
Keyword(s):  
Weight Percent ◽  
Precipitation Method ◽  
Temperature Programmed Reduction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Areas ◽  
Temperature Programmed ◽  
Co Precipitation ◽  
Adsorption Desorption

The NiO-ZnO binary materials had been prepared by co-precipitation method. The weight percent of nickel of NiO-ZnO materials were 5, 10 and 20; they were pretreated under air at temperature of 300, 500 and 700°C, respectively. The characterization of NiO-ZnO materials were the thermal gravity analysis(TGA), X-ray diffraction(XRD), N2 adsorption-desorption at 77K, scaning electron microscope(SEM) and temperature-programmed reduction(TPR). The results revealed that surface areas of NiO-ZnO materials order from large to small were 20NiZn(OH)x(66 m2·g-1) > 10NiZn(OH)x(34 m2·g-1) > 5NiZn(OH)x(9 m2·g-1) after being calcined at the temperature of 500°C. Further, NiO-ZnO materials had two main reductive peaks at 390-415°C and 560-657°C, respectively. In all NiO-ZnO materials, 20NiZn(OH)x-C500 material had the highest surface area and the best interaction between NiO and ZnO.

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