PREPARATION OF ZnO:Tm, Gd AND ITS FLUORESCENCE PROPERTIES

2012 ◽  
Vol 19 (05) ◽  
pp. 1250048
Author(s):  
LIMIN DONG ◽  
YOU LI ◽  
QIN LI ◽  
LIANWEI SHAN ◽  
ZHIDONG HAN ◽  
...  
Keyword(s):  
Sintering Temperature ◽  
Fluorescence Properties ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Scanning Electronic Microscopy ◽  
Electronic Microscopy ◽  
High Quality ◽  
X Ray ◽  
Co Precipitation ◽  
Heat Preservation

ZnO:Tm , Gd materials with high quality blue light emissions were successfully prepared using the chemical co-precipitation method. The surface morphology, composition, crystal structure and fluorescence properties were investigated using the thermogravimetric analysis/differential thermal analysis (TG/DTA), scanning electronic microscopy (SEM), X-ray diffraction (XRD), and photoluminescence (PL). The results showed that the lowest sintering temperature was 580°C; the optimal sintering temperature was 900°C; ZnO:Tm3+ , Gd3+ had two emission peaks: 1 D 2→3 H 4 and 1 G 4→3 H 6; the optimal heat preservation time was 3 h; the proportion of matrix and doping elements was 100:2; and the optimal proportion of Tm and Gd was 3:2.

Effect of Sintering Temperature on MAl2O4 Catalysts Used for the Catalytic Pyrolysis of Microalgae

2013 ◽  
Vol 773 ◽  
pp. 508-513
Author(s):  
Yu Wei Zha ◽  
Juan Liu ◽  
Xiu Qin Yang ◽  
Xia Li
Keyword(s):  
Catalytic Pyrolysis ◽  
Sintering Temperature ◽  
Catalyst Activity ◽  
X Ray Diffraction ◽  
Scanning Electronic Microscopy ◽  
Electronic Microscopy ◽  
Heating Value ◽  
X Ray ◽  
Co Precipitation

A series of MAl2O4(M=Ni2+and Mg2+) catalysts with high catalyst activity was prepared via co-precipitation. Higher sintering temperature is favorable to catalyst activity. As-prepared MAl2O4catalysts were characterized by X-ray diffraction, scanning electronic microscopy, and BrunauerEmmettTeller method. MAl2O4catalysts were evaluated using the heating values of bio-oils derived from the catalytic pyrolysis of microalgae. The heating value of the bio-oils is enhanced along with the increased sintering temperature of MAl2O4catalysts. The highest heating value using MAl2O4catalysts sintered at 700 °C was 36.298 MJ/kg, which was higher than the value when using ZSM-5.

Synthesis and Characterization of Magnetite Particles by Co-Precipitation Method

2012 ◽  
Vol 512-515 ◽  
pp. 82-85 ◽  
Author(s):  
Ming Ya Li ◽  
Xu Dong Sui
Keyword(s):  
Spinel Structure ◽  
Bath Temperature ◽  
Precipitation Method ◽  
Scanning Electronic Microscopy ◽  
Electronic Microscopy ◽  
X Ray ◽  
Magnetite Particles ◽  
Co Precipitation ◽  
Different Diameters

The Fe3O4 nanoparticles with different diameters were prepared by co-precipitation method in this paper. Magnetite particles with different diameters were fabricated by changing the concentration of the reactants and the reaction temperature. The influences of process parameters on the microstructure and properties of magnetic nanopariticles were studied. The obtained samples were characterized by X-ray powder diffraction and scanning electronic microscopy. Besides, vibrating sample magnetmeter was used to characterize the magnetic properties. The results show that all the as-synthesized magnetite nanoparticles are well crystallized and can be indexed into spinel structure. The appearance and magnetism of the particles with different diameter are different from each other. When the ratio of Fe3+ and Fe2+ is 2:1 or 4:3, the product was pure and good crystalline. Furthermore, higher saturation magnetization was obtained in a higher bath temperature.

Y3Al5O12 Nanocrystallites Prepared from a Novel Crystalline Precursor

2011 ◽  
Vol 306-307 ◽  
pp. 1142-1147 ◽  
Author(s):  
Rong Jiang Han ◽  
Dan Gao ◽  
Ke Zheng Chen
Keyword(s):  
Precipitation Method ◽  
Test Results ◽  
X Ray Diffraction ◽  
Electronic Microscopy ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Air Atmosphere ◽  
Thermal Gravimetry ◽  
Measured Weight ◽  
Co Precipitation

A novel crystalline precursor for preparing Y3Al5O12 (YAG) nanocrystallite was synthesized via a co-precipitation method using (NH4)2CO3 solution as the precipitator. The precursor was characterized by means of powder X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), thermal gravimetry (TG), differential thermal gravimetry (DTG) and differential scanning calorimetry (DSC), respectively. The empirical chemical formula of the crystalline precursor can be expressed as 5[(NH4)2Al6(CO3)3(OH)14]×9[Y2(CO3)3×3H2O] according to the test results. The measured weight loss of 46.7% of the precursor without consideration of the absorbed water is in accord with the calculated value of 47.5% according to the above empirical formula. The phase-pure YAG nanocrystallites were obtained by calcining the above precursors at 900°C for 2 hours in air atmosphere. Transmission electronic microscopy (TEM) result showed that the particle size of YAG nanocrystallites is 40-80 nm. The mechanism of themal decomposition of the crystalline precursor was also presented.

Effect of Sintering Temperature on Structural and Electrical Transport Properties of (La0.7Ca0.3MnO3)0.97/(ZnO)0.03 Composite

2013 ◽  
Vol 378 ◽  
pp. 202-208
Author(s):  
Ho Je Cho ◽  
Seung Rok Lee ◽  
M.S. Anwar ◽  
Hang Joo Ko ◽  
Bon Heun Koo
Keyword(s):  
Electrical Transport ◽  
Sintering Temperature ◽  
X Ray Diffraction ◽  
Scanning Electronic Microscopy ◽  
Electronic Microscopy ◽  
Electrical Transport Properties ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Electrical And Magnetic Properties ◽  
New Phase

The composites of (La0.7Ca0.3MnO3)0.97/(ZnO)0.03were fabricated with having different sintering temperature by conventional solid state reaction methods, and their magnetoresistance (MR) properties and electrical transport were investigated. The result of scanning electronic microscopy (SEM) and X-ray diffraction (XRD) indicated that no new phase appeared in the composites except LCMO and ZnO phases. specially, SEM results show that with increment of sintering temperature, the grain size of La0.7Ca0.3MnO3also increases, which plays a key on electrical and magnetic properties of the (La0.7Ca0.3MnO3)0.97/(ZnO)0.03composites. The electrical transport and magnetic was measured over a temperature range of 90 320K. tables etc. (2012H1B8A2026212), (NIPA-2013-H0301-13-2009)

scholarly journals Pembuatan Ba0,8Sr0,2TiO3 menggunakan Metode Co-precipitation dengan Variasi Suhu Sintering

2017 ◽  
Vol 7 (1) ◽  
pp. 51
Author(s):  
Isma Alvia Nita ◽  
Yofentina Iriani ◽  
Fahru Nurosyid
Keyword(s):  
Dielectric Constant ◽  
Crystal Size ◽  
Sintering Temperature ◽  
Microstructure Characterization ◽  
Temperature Measurements ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lcr Meter ◽  
Co Precipitation

<p>Ba<sub>0,8</sub>Sr<sub>0,2</sub>TiO<sub>3 </sub>was made by co-precipitation method with the sintering temperature of 600<sup>o</sup>C, 700<sup>o</sup>C, 800<sup>o</sup>C and 900<sup>o</sup>C for 4 hours. Sintering temperature was varied to investigate its effect on microstructure and dielectric constant of Ba<sub>0,8</sub>Sr<sub>0,2</sub>TiO<sub>3</sub>. microstructure characterization was performed by X-Ray Diffraction (XRD) instrument. Dielectric constant characterization was perform by LCR meter. The crystal size increased significantly with increasing sintering temperature. Measurements of dielectric constant were performed at range of frequency 0.01 to 100 KHz. Dielectric constant value is highest at the lowest frequency. Dielectric constant value size increased significantly with increasing sintering temperature.</p>

Effect of Sintering Conditions on the Properties of Mn-Zn Ferrites Produced by Co-Precipitation

2011 ◽  
Vol 391-392 ◽  
pp. 839-843 ◽  
Author(s):  
Gui Xin Wang ◽  
Hong Xia Wu ◽  
Yan Fei Jiang ◽  
Hui Fen Peng ◽  
Xin Wang
Keyword(s):  
Heating Rate ◽  
Sintering Temperature ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Sintering Atmosphere ◽  
X Ray ◽  
Dry Pressing ◽  
Vibration Sample Magnetometer ◽  
Co Precipitation ◽  
Quality Factor Q

Mn0.49Zn0.48Fe2.06O4ferrite nano-powders were prepared by co-precipitation method and pressed into ring samples by dry pressing to study the effect of sintering atmosphere, sintering temperature and heating rate on properties of Mn-Zn Ferrites. X ray diffraction (XRD), scanning electron microscopy (SEM), and vibration sample magnetometer (VSM) were used to characterize properties of the obtained samples. It was shown that the samples sintered in nitrogen contained no impurities with cubic spinel structure. The samples sintered at 880°C with heating rate of 5°C/min had a density of 4.82 g•cm-3, high quality factor Q of 57 at a frequency of 2MHz, high saturation magnetization Ms of 90.02emu•g-1.

Synthesis Mechanism and Microstructure Characterization of BaIn2O4

2011 ◽  
Vol 347-353 ◽  
pp. 1342-1347 ◽  
Author(s):  
Ping Ren ◽  
Li Cheng Zhou ◽  
Jun Xi Zhang ◽  
Hong Yun
Keyword(s):  
Sintering Temperature ◽  
Precipitation Method ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Synthesis Mechanism ◽  
X Ray ◽  
Grain Sizes ◽  
Co Precipitation

The synthesis mechanism and microstructures of BaIn2O4 particles were analyzed by simultaneous thermogravimetry - differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), and scanning electron microscope (SEM). Firstly, In(OH)3 and BaCO3 precursors were prepared by the co-precipitation method. Next, during the sintering process In(OH)3 initially decomposed into In2O3 and water, and then BaCO3 reacted with In2O3 to synthesize Ba4In6O13. Finally, Ba4In6O13 and In2O3 further reacted to form BaIn2O4. The obtained BaIn2O4 particles were in monoclinic structure and exhibited high crystal quality. The grains were tightly bound together and their boundaries became blurry. The grain sizes increased with increasing the sintering temperature.

scholarly journals Photoluminescent Properties of Hydroxyapatite and Hydroxyapatite/Multi-Walled Carbon Nanotube Composites

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 832
Author(s):  
Edna X. Figueroa-Rosales ◽  
Javier Martínez-Juárez ◽  
Esmeralda García-Díaz ◽  
Daniel Hernández-Cruz ◽  
Sergio A. Sabinas-Hernández ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Hexagonal Phase ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Multi Walled Carbon Nanotube ◽  
Nanotube Composites ◽  
Carbon Nanotube Composites ◽  
Co Precipitation ◽  
Functionalized Mwcnts

Hydroxyapatite (HAp) and hydroxyapatite/multi-walled carbon nanotube (MWCNT) composites were obtained by the co-precipitation method, followed by ultrasound-assisted and microwave radiation and thermal treatment at 250 °C. X-ray diffraction (XRD) confirmed the presence of a hexagonal phase in all the samples, while Fourier-transform infrared (FTIR) spectroscopy elucidated the interaction between HAp and MWCNTs. The photoluminescent technique revealed that HAp and the composite with non-functionalized MWCNTs present a blue luminescence, while the composite with functionalized MWCNTs, under UV-vis radiation shows an intense white emission. These findings allowed presentation of a proposal for the use of HAp and HAp with functionalized MWCNTs as potential materials for optoelectronic and medical applications.

Photocatalytic Activity of Fe-Doped ZnO/Montmorillonite Nanocomposite for Degradation of Malachite Green

2015 ◽  
Vol 827 ◽  
pp. 19-24 ◽  
Author(s):  
Nur Afifah ◽  
Nadia Febiana Djaja ◽  
Rosari Saleh
Keyword(s):  
Photocatalytic Activity ◽  
Malachite Green ◽  
Organic Dyes ◽  
Uv Light ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Spin Resonance ◽  
Doped Zno ◽  
Co Precipitation

In this study, the photocatalytic activity of pure Fe- doped ZnO and Fe- doped ZnO/Montmorillonite nanocomposite has been investigated for the degradation of malachite green under UV light irradiation. Both photocatalysts were synthesized using co-precipitation method and characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, Fourier-transform infrared absorption, and electron spin resonance. The results showed that the photocatalytic efficiency is better in the presence of montmorillonite compared to pure Fe- doped ZnO. To detect the possible reactive species involved in degradation of organic dyes control experiments with introducing scavengers into the solution of organic dyes were carried out. It is found that electron plays an important role in the degradation of malachite green.

Template Induced Synthesis of Nano-Hydroxyapatite by Co-Precipitation Method

2011 ◽  
Vol 311-313 ◽  
pp. 1713-1716 ◽  
Author(s):  
Yan Rong Sun ◽  
Tao Fan ◽  
Chang An Wang ◽  
Li Guo Ma ◽  
Feng Liu
Keyword(s):  
Electron Microscope ◽  
Chondroitin Sulfate ◽  
Aspartic Acid ◽  
Transmission Electron Microscope ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure And Morphology ◽  
Transmission Electron ◽  
Co Precipitation

Nano-hydroxyapatite with different morphology was synthesized by the co-precipitation method coupled with biomineralization using Ca(NO3)2•4H2O and (NH4)2HPO4 as reagents, adding chondroitin sulfate, agarose and aspartic acid as template. The structure and morphology of the prepared powders were characterized by X-ray diffraction (XRD) and transmission electron microscope (TEM).

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