Sol-Gel Synthesis and Characterization of BaAl2O4 and Co: BaAl2O4 Nanoparticles

2010 ◽  
Vol 148-149 ◽  
pp. 1067-1070 ◽  
Author(s):  
Cai Na Luan ◽  
Jin Ma ◽  
Zhen Zhu ◽  
Ling Yi Kong ◽  
Qiao Qun Yu

In this paper, we prepared BaAl2O4 and Co:BaAl2O4 nanoparticles from aqueous solution of metal nitrates containing citric acid as a chelating agent by sol-gel method. The gel was heat-treated at temperatures ranging from 710°C to 1000°C. The heat-treated powders were characterized by X-ray diffraction analysis (XRD), infrared spectra (IR) and luminescence spectroscopy. From the results of the characterization, we find the prepared powders are pure nano-particles of BaAl2O4 after heat-treated at 900°C temperature. The emission spectra of Co: BaAl2O4 in the visible region indicates the existence of Co2+ in the tetrahedral sites of BaAl2O4 nano-crystal.

2019 ◽  
Vol 8 (3) ◽  
pp. 209
Author(s):  
Fatima Zahra Krimech ◽  
Salaheddine Sayouri ◽  
Taj-Edine Lamcharfi ◽  
Fatima Zahra Ahjyaje

<p>Pure phase Li<sub>2</sub>TiO<sub>3 </sub>nano-particles were synthesized by the sol-gel method and the structural properties were examined with X-ray diffraction (XRD) technique. The latter showed that these materials, heat treated at relatively low temperature 900°C during 4h compared to the conventional solid-state reaction which calcination temperature is about 900–1100°C for 10 h; crystallize in the monoclinic phase without the presence of secondary phases. The microstructure of the LT ceramic (sintered at 1100°C) were determined by SEM and a good crystalline nature was observed with an average of granular size 2 μm. Moreover, the impedance spectroscopy showed at a higher temperature of 500°C the low-frequency arc due either to the grain boundary or sample-electrode charge transport processes.</p>


2018 ◽  
Vol 762 ◽  
pp. 273-277
Author(s):  
Anzelms Zukuls ◽  
Gundars Mežinskis ◽  
Aigars Reinis ◽  
Ingus Skadins ◽  
Juta Kroica ◽  
...  

SnO2-TiO2 sol-gel coatings on soda-lime silicate glass heat treated at 500 °C and xerogel specimens also heat treated at 500 °C were investigated in this study. The morphology of 1, 3, 5 and 7 mol% SnO2 doped titanium oxide coatings were evaluated with a scanning electron microscope (SEM), an atomic force microscope (AFM) and an UV-VIS light spectrophotometer, whilst xerogel structure was analysed with X-ray diffraction spectroscopy (XRD). The physicochemical properties of the TiO2-SnO2 systems depended mainly on the Sn-to-Ti ratio. The surface morphology of the layer was compact and homogeneous with no visible cracks. Anatase and rutile phase was found in the tested 1, 3, 5, 7 and 10 mol% SnO2 doped and heat treated xerogel specimens. Rutile phase content in the heat treated xerogel was reduced, if Sn4+ content was increased. Photocatalytic activity and antibacterial properties were evaluated as well.


2011 ◽  
Vol 412 ◽  
pp. 125-128 ◽  
Author(s):  
Ming Ya Li ◽  
Xiao Yan Wang ◽  
Cheng Li Ye ◽  
Feng Lin Xue

The Bi-2223 powders were fabricated by the sol-gel technique. Metal nitrates were used as starting materials, and ethylenediamineteracetic acid was used as chelating agent. The solution was heated until it turns to gel. Then the organic was removed at a temperature of 240°C, and the nitrite was removed at 500°C. The powder was calcined at different temperature, varying the dwelling time. Experimental results show that the main phase of samples after heat treatment is Bi-2212 phase.


2013 ◽  
Vol 457 (1) ◽  
pp. 82-88 ◽  
Author(s):  
Patama Visuttipitukul ◽  
Pat Sooksaen ◽  
Niti Yongvanich

2010 ◽  
Vol 434-435 ◽  
pp. 214-216 ◽  
Author(s):  
Ji Ming Zhang ◽  
Dong Lin Zhao ◽  
Zeng Min Shen

Abstract. Green light emitting Mn2+-doped Zn2SiO4 (Zn2SiO4:Mn2+) phosphor nano-particles were synthesized by sol-gel method combined with a furnace firing from the sol-gel solution made with ZnO, MnCO3 and tetraethoxysilan. The influences of annealing temperatures on the microstructures and photoluminescent properties of the Zn2SiO4:Mn2+ phosphors were investigated. The structural details of the phosphors were examined through XRD and SEM. The photoluminescent properties of the Zn2SiO4:Mn2+ phosphors were characterized by excitation and emission spectra. The results indicate that the XRD patterns of the Zn2SiO4:Mn2+ phosphors exhibit a willemite structure (-Zn2SiO4). Green photoluminescence whose emission peak is located at 525 nm were observed from the synthesized phosphor particles under UV excitation. The photoluminescent mechanisms of the Zn2SiO4:Mn2+ phosphors were discussed.


2015 ◽  
Vol 3 (8) ◽  
pp. 1716-1723 ◽  
Author(s):  
Alexander Rehmer ◽  
Kerstin Scheurell ◽  
Erhard Kemnitz

For the first time transparent antireflective CaF2-coatings were prepared from clear CaF2-sols obtained via the fluorolytic sol–gel synthesis and containing homo-dispersed CaF2 nano-particles.


2008 ◽  
Vol 23 (8) ◽  
pp. 2053-2060 ◽  
Author(s):  
S. Smitha ◽  
P. Shajesh ◽  
P. Mukundan ◽  
K.G.K. Warrier

A new organic–inorganic hybrid synthesized through a sol-gel process starting from alkoxysilane and chitosan is reported. Functionalization of the hybrid was effected through in situ hydrolysis–condensation reaction of methyltrimethoxysilane (MTMS) and vinyltrimethoxysilane (VTMS) in the reaction medium. The process yields highly transparent and hydrophobic silica–chitosan hybrids. The hybrid gel was investigated with respect to chemical modification, thermal degradation, hydrophobicity, and transparency under the ultraviolet-visible region. The extent of hydrophobicity had been tailored by varying the precursor ratio. SiO2–chitosan–MTMS hybrids showed a higher thermal stability than SiO2–chitosan–VTMS (SCV) hybrids with respect to hydrophobicity. Condensation of silsesquioxanes generated from the hydrolysis of MTMS and VTMS over the silica-chitosan particles impart hydrophobicity to the hybrid. The coatings of functionalized SiO2–chitosan precursor sol on glass substrates showed nearly 100% optical transmittance in the visible region. The present hybrid material may find application in optics and other industries.


2012 ◽  
Vol 512-515 ◽  
pp. 360-363 ◽  
Author(s):  
Jie Xu ◽  
Ming Ya Li ◽  
Xiao Yan Wang

In this study, Bi2Sr2CaCu2Ox (Bi-2212) thick films on Ag substrate were fabricated using the dip-coating method. Firstly, the Bi-2212 powders were prepared by Sol-Gel process. Metal nitrates were used as starting materials and ethylenediaminetetracetic acid (EDTA) was used as chelating agent. Secondly, the resulting powders were used as solute, and polyvinyl butyral (PVB) was used as solvent to prepare suspension via stirring and ultrasonic vibration. Then the suspension was dip-coated on Ag substrate. After heat treatments, the phase compositions of the samples were characterized using the XRD. The microstructure was observed using SEM. Experimental results show that the sintering temperature strongly influence the phase formation of Bi–2212.


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