Preparation of TiO2 Coatings on Carbon Fibers

2022 ◽  
Vol 1049 ◽  
pp. 117-123
Author(s):  
Rida Gallyamova ◽  
Rustam Safiullin ◽  
Vladimir Dokichev ◽  
Fanil F. Musin

Carbon fibers have been TiO2 coated. Previously, the carbon fiber surface has been heat-treated to remove the sizing. The TiO2 layer has been formed on the fiber surface using the sol-gel technique by immersion in a solution. After coating, the samples have been dried at room temperature and annealed at 500 °C in air for 30 minutes. The phase composition of the coating obtained has been studied using X-ray diffraction. X-ray diffraction analysis of the coating and sol has shown that the rutile phase and the average size of TiO2 crystallites grow with an increase in the annealing temperature. The results of studying TiO2 coating antioxidative properties within 500-800 °C are given. Studying the morphology of the TiO2 coating on the fiber surface and the burnout rate (weight change) have shown that the coating exhibits good oxidation resistance up to 600 °C.

2012 ◽  
Vol 535-537 ◽  
pp. 2240-2244
Author(s):  
Wei Wei ◽  
Chang Shun Yu ◽  
Shao Jun Wang ◽  
Qing Da An

Nanosized TiO2 particles were synthesized by sol-gel method using ionic liquid as assistant. The samples were characterized by UV-vis diffuse reflectance spectra, X-ray diffraction (XRD), transmission electron microscopy (TEM). It was shown that the phase detectable was mainly rutile phase with uniform sphericity and the average size was 10nm. Along with the rise of sintering temperature, grain diameter became bigger. The photocatalytic activities of nanosized TiO2 were evaluated by the reduction yield in the presence of CO2 and water. The result showed that TiO2 catalysts has efficient photocatalytic activities, of which made with [OMIM]BF4 displayed the highest photocatalytic active in the experiment.


2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Aidong Tang ◽  
Yuehua Deng ◽  
Jiao Jin ◽  
Huaming Yang

A novel nanocomposite ZnFe2O4-TiO2/MCM-41 (ZTM) was synthesized by a sol-gel method and characterized through X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), N2adsorption-desorption, Raman spectroscopy, and ultraviolet visible (UV-vis) spectrophotometry. The results confirmed the incorporation of ZnFe2O4-TiO2nanoparticles inside the pores of the mesoporous MCM-41 host without destroying its integrity. ZnFe2O4nanoparticles can inhibit the transformation of anatase into rutile phase of TiO2. Incorporation of ZnFe2O4-TiO2within MCM-41 avoided the agglomeration of nanoparticles and reduced the band gap energy of TiO2to enhance its visible light photocatalytic activity. UV-vis absorption edges of ZTM nanocomposites redshifted with the increase of Zn/Ti molar ratio. The nanocomposite approach could be a potential choice for enhancing the photoactivity of TiO2, indicating an interesting application in the photodegradation and photoelectric fields.


2012 ◽  
Vol 66 (3) ◽  
Author(s):  
Khaled Haouemi ◽  
Fathi Touati ◽  
Néji Gharbi

AbstractTiO2 nanoparticles with different shapes and sizes were synthesised by the sol-gel route in Water/Brij78/Hexane reverse microemulsions. The aqueous cores of these microemulsions were used as nanoreactors to control sol-gel reactions. We studied the effect of water/surfactant mole ratio (W 0) on the morphology, and textural properties of the final products. The materials thus obtained were characterised by different techniques. Thermogravimetric and differential thermal analysis (TG-DTA) was used to study the thermal behaviour of the products and X-ray diffraction (XRD) to identify the crystalline phases. The morphological and textural properties of the products were determined by scattering electron microscopy (SEM) and the Brunauer-Emmett-Teller (BET) method, respectively. We also studied the influence of thermal treatment on the structure and size of the TiO2 particles. The effect of W 0 on the anatase-rutile phase transition temperature was investigated.


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.


1994 ◽  
Vol 346 ◽  
Author(s):  
Carol S. Houk ◽  
Gary A. Burgoine ◽  
Catherine J. Page

ABSTRACTWe have investigated the homogeneity of sol‐gel derived YBa2Cu307‐s from the solution phase to the final product using transmission electron microscopy (TEM), x‐ray diffraction (XRD), and Energy Dispersive X‐ray (EDX) lateral mapping techniques. The starting solutions contain stoichiometric amounts of the metal 2‐(2‐methoxyethoxy)ethoxide components in 2‐(2‐methoxyethoxy)ethanol and appear to be homogeneous by TEM with a uniform distribution of particles having an average size of less than 40 â. Through elemental mapping we see elemental segregation in the high temperature (950 °C) products, which are orthorhombic by XRD. In elemental maps of gel samples fired to 700 °C, which are tetragonal by XRD, we also see elemental inhomogeneity within particles and phase zoning in maps of products from finely ground gels. A comparison of elemental maps and x‐ray diffraction patterns of the products from gel processing and conventional solid state processing is made.


2002 ◽  
Vol 35 (5) ◽  
pp. 577-580 ◽  
Author(s):  
Zein Heiba ◽  
Hasan Okuyucu ◽  
Y. S. Hascicek

Nanosized polycrystalline samples of (Er1−uGdu)2O3(0 ≤u≤ 1.0) were synthesized by a sol–gel technique. X-ray diffraction data were collected and the crystal structures were refined by the Rietveld method. All samples are found to have the same crystal system and formed solid solutions over the whole range ofu. The Er3+and Gd3+ions were randomly distributed over two cationic sites, 8band 24d, in the space groupIa\bar{3} (206) in all refined structures. The lattice parameter was found to vary non-linearly with the composition (u). The average microstrain and average crystallite size have been calculated from the Williamson–Hall plots for each sample. The average size ranges from 50 to 70 nm, and the microstrain from 0.4 to 1.7%.


2012 ◽  
Vol 727-728 ◽  
pp. 9-13
Author(s):  
Suzana Arleno S. Santos ◽  
Eduardo Sousa Lima ◽  
Luis Henrique Leme Louro ◽  
Célio Albano da Costa

This study aimed to produce nanometric powders of alumina by sol-gel route. Six samples were produced by varying the amount of water for dilution of aluminum nitrate and the calcination temperature. The final products were evaluated by thermogravimetric analysis, scanning electron microscopy, X-ray diffraction and particle size. It could be noticed that, beyond the time of gelation and calcination temperature, the addition of water also influenced the average size of the clusters.


1987 ◽  
Vol 2 (6) ◽  
pp. 850-857 ◽  
Author(s):  
T. Hamada ◽  
T. Nishida ◽  
Y. Sajiki ◽  
M. Matsumoto ◽  
M. Endo

Carbon fibers having various types of structures were prepared by spinning coal tar mesophase pitch, followed by thermosetting and heat treatment at high temperature. Two kinds of spinning—spinning with stirring the pitch above a capillary and without stirring—have been tried to form pitch fibers from coal tar mesophase pitch. Carbon fibers obtained from mesophase pitch and spun without stirring have a radial transverse structure where the graphite layers are arranged radially in the transverse cross section of the fibers. Carbon fibers made with a stirring system can have random, onion, and a novel “quasionion structure” by changing the spinning conditions. Carbon fibers spun with stirring are less graphitizable than those spun without stirring. No separation of the ten diffraction bands into 100 and 101 peaks and no appearance of a 112 peak were observed by x-ray diffraction when the fibers were heat treated at 2700°C, whereas carbon fibers spun without stirring show clear evidence of graphitization by heat treatment at 2700°C. Transverse magnetoresistance effects at 77 K, (Δρ/ρ)t have been measured to characterize the structure of the carbon fibers. The carbon fibers spun with stirring and heat treated at 2500°C generally exhibit a negative transverse magnetoresistance effect, whereas the carbon fibers spun without stirring exhibit a positive magnetoresistance. Good correlations are found among d002, Lc (002), transverse magnetoresistance, and resistivity at room temperature of carbon fibers spun under various conditions and heat treated at 2500°C. The tensile strengths (TS) of carbon fibers that are less graphitized are higher than those of carbon fibers with a higher degree of graphitization if tensile moduli (TM) are almost constant.


2007 ◽  
Vol 7 (12) ◽  
pp. 4402-4411 ◽  
Author(s):  
Soumen Das ◽  
Soumen Basu ◽  
Gautam Majumdar ◽  
Dipankar Chakravorty ◽  
S. Chaudhuri

Sol–gel synthesized SnO2 nanoparticles with an average size of 2.0 nm obtained at 373 K were gradually annealed to 673 K in air for 25 minutes. Sequentially taken transmission electron microscopy (TEM) images showed that particle agglomeration of these non-matrix SnO2 nanocrystals was a very slow process. The blue shifts of the band gap (∼ 2.3 eV) obtained from the optical absorbance spectra were matched with the theoretical results of the size related excitonic binding energies. These calculations also supported the observed slow grain growth. The depth sensitive hardness measurements of the thin films indicated hardness in the range of 5.03 GPa to 6.79 GPa. These undoped and non-matrix SnO2 nanoparticles were also investigated with the X-ray photoelectrons spectroscopy (XPS), atomic force microscope (AFM), X-ray diffraction spectroscopy (XRD), and ac impedance analyzer.


2017 ◽  
Vol 47 ◽  
pp. 54-59 ◽  
Author(s):  
Dae Han Lee ◽  
Ji Young Ock ◽  
Jeong Hoon Son ◽  
Dong Sik Bae

YCrxAl1-xO3 nanoparticles were synthesized by a reverse micelle processing for inorganic pigment. Y(NO3)2·6H2O, Cr (NO3)2·6H2O and Al (NO3)3·9H2O are used for precursors in order to synthesis YCrxAl1-xO3 nanoparticles. The aqueous solution consists of mixing the molar ratio of Y/Cr/Al at 1:x:1-x and heat treated at 900~1300°C for 2h. The average size and distribution of synthesized YCrxAl1-xO3 powders was in the range of 10-20nm and narrow, respectively. The average size of the synthesized YCrxAl1-xO3 powders increased with increasing water to surfactant molar ratio and heating temperature. The crystallinity of synthesized YCrxAl1-xO3 powder increased with increasing heating temperature. The synthesized YCrxAl1-xO3 powders were characterized by X-ray diffraction analysis (XRD), field emission scanning electron microscopy (FE-SEM) and color spectrophotometer. The properties of the synthesized powders were affected by such variables as molar ratio, heating temperature etc.


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