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1.
Guanhua Gao Rongrong Shi Wenqing Qin Youguo Shi Guofu Xu Guanzhou Qiu Xiaohe Liu 《Journal of Materials Science》2010,45(13):3483-3489
Monodisperse Fe3O4 nanoparticles with narrow size distribution could be successfully synthesized in large quantities by a facile solvothermal
synthetic method in the presence of oleic acid and oleylamine. Well-defined assembly of uniform nanoparticles with average
sizes of 8 nm can be obtained without a further size-selection process. The sizes of final products could be readily tuned
from 5 to 12 nm by adjusting the experimental parameters such as reaction time, temperature, and surfactants. The phase structures,
morphologies, and magnetic properties of the as-prepared products were investigated in detail by X-ray diffraction, transmission
electron microscopy, selected area electron diffraction, high-resolution transmission electron microscopy, and magnetometry
with a superconducting quantum interference device. The magnetic study reveals that the as-synthesized nanoparticles are ferromagnetic
at 2 K while they are superparamagnetic at 300 K. 相似文献
2.
Baozhan Zheng Minghui Zhang Dan Xiao Yong Jin Martin M. F. Choi 《Inorganic Materials》2010,46(10):1106-1111
A simple and quick microwave method to prepare high performance magnetite nanoparticles (Fe3O4 NPs) directly from Fe has been developed. The as-prepared Fe3O4 NPs product was fully characterized by X-ray diffraction, transmission electron microscopy and scanning electron microscopy.
The results show that the as-prepared Fe3O4 NPs are quite monodisperse with an average core size of 80 × 5 nm. The microwave synthesis technique can be easily modified
to prepare Fe3O4/Ag NPs and these NPs possess good magnetic properties. The formation mechanisms of the NPs are also discussed. Our proposed
synthesis procedure is quick and simple, and shows potential for large-scale production and applications for catalysis and
biomedical/biological uses. 相似文献
3.
Hui Shun Chin Kuan Yew Cheong Khairunisak Abdul Razak 《Journal of Materials Science》2011,46(15):5129-5139
Antimony trioxide (Sb2O3) nanoparticles with particle sizes ranging from 2 to 12 nm, spherical in shape, and well-distributed were successfully synthesized
by chemical reduction method. The nanoparticles were synthesized in the presence of hydrazine as a reduction agent in ethylene
glycol through the reaction between antimony trichloride and sodium hydroxide. Effects of reaction temperature, reaction time,
precursor concentration and boiling temperature on the particle size, shape, and distribution of the Sb2O3 nanoparticles were investigated. Morphology of the nanoparticles was examined by transmission electron microscope (TEM).
It was revealed that the particle size increased when reaction temperature, reaction time and concentration of precursor were
increased. Moreover, the mixture needed to be boiled prior to the addition of hydrazine as a reduction agent, in order to
obtain an optimum reduction. X-ray diffraction (XRD) was employed to study the crystallinity and phase of the nanoparticles.
The nanoparticles were determined as cubic phase of Sb2O3 (ICDD file no. 00-043-1071) by XRD. Interrelation between UV–vis absorption spectra of the nanoparticles and their particle
size were obtained. 相似文献
4.
In(OH)3 and In2O3 nanocrystals of rectangular shape and incorporating Au were synthesized with a hydrothermal process and thermal decomposition.
Powder X-ray diffraction, electron microscopy (SEM, TEM), and energy-dispersive spectroscopy studies reveal that elemental
Au nanoparticles are dispersed on the surface of In(OH)3 rectangular nanocrystals and incorporated into In2O3 nanoporous particles. UV–vis spectral measurements reveal a surface-enchanced plasma band near λ ~532 nm for both Au-incorporating
nanomaterials. The BET surface areas of Au-incorporating In(OH)3 and In2O3 are 26.2 and 35.5 m2/g, respectively. The incorporation of elemental Au in In(OH)3 and In2O3 nanomaterials is attractive for sensor, catalyst and solar-cell applications. 相似文献
5.
Using electrophoretic deposition (EPD), we have produced YSZ individual ceramic coatings and YSZ/Al2O3 composite coatings for a wide range of applications in modern materials research. YSZ and Al2O3 nanopowders were prepared by high-energy physical dispersion techniques, namely, by a laser evaporation–condensation process and electroexplosion of wire, respectively. Stable nonaqueous suspensions for the EPD process have been prepared using YSZ and Al2O3 nanopowders with an average particle size of 11 and 22 nm, respectively. The YSZ/Al2O3 composite coating produced by sintering at 1200°C has been shown to have higher density in comparison with the YSZ individual coating produced at the same temperature. X-ray diffraction characterization showed that the YSZ/Al2O3 composite coating consisted of two crystalline phases: α-Al2O3 (corundum) (42 wt %) and cubic ZrO2〈Y2O3〉 (58 wt %). Quantitative analysis of electron micrographs of the surface of the films showed that the YSZ individual coating produced by sintering at 1200°C had a loose structure and contained pores (9%), as distinct from the composite coating, which had a dense, porefree grain structure. 相似文献
6.
A pure aluminum matrix composite reinforced by Bi2O3-coated Al18B4O33 whisker was fabricated by squeeze casting method. The effects of Bi2O3 coating on the whisker/matrix wettability and the ultimate tensile strength and elongation to fracture of the composite are
investigated. The results show that Bi2O3 coating can react with aluminum matrix during casting process, which improves the whisker/matrix wettability. Moreover, the
ultimate tensile strength and elongation to fracture of the composite attain the maximum values at the mass ratio of 40:1
between whisker and Bi2O3 coating. 相似文献
7.
Changhyun Jin Hyunsoo Kim Kyungjoon Baek Hyoun Woo Kim Chongmu Lee 《Journal of Materials Science: Materials in Electronics》2010,21(11):1154-1158
TiO2-sheathed Ga2O3 one-dimensional (1D) nanostructures were synthesized by thermal evaporation of GaN powders and then sputter-deposition of
TiO2. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis results indicate that the Ga2O3 cores are of a single crystal nature with a monoclinic structure while the TiO2 shells are amorphous. Photoluminescence (PL) emission is slightly decreased in intensity by TiO2 coating, but it is significantly increased by thermal annealing in an oxygen atmosphere. The emission peak is also shifted
from ~500 to ~550 nm by oxygen annealing. The increase in the green emission is due to the increase in the concentration of
the Ga vacancies in the cores by the inflow of oxygen during oxygen annealing. On the other hand, annealing in a nitrogen
atmosphere leads to a red shift of the emission to ~700 nm originating from nitrogen doping. 相似文献
8.
W. Skoneczny 《Materials Science》2010,46(2):276-281
The paper presents the characterization of obtaining Al2O3 oxide layers on AlMg2 aluminum alloy as a result of hard anodizing by the electrolytic method in a three-component electrolyte. The Al2O3 layers obtained on the AlMg2 alloy in the three-component SBS electrolyte were subjected to detailed microstructural investigations (by means of a scanning
electron microscope). By using X-ray diffraction, the phase compositions of obtained oxide layers were examined. It was found
that the Al2O3 oxide layers obtained via hard anodizing in a three-component electrolyte are amorphous. The chemical composition of the
Al2O3 layers is presented and compared with the results of stechiometric calculations for the Al2O3 layer. Surface morphologies of the obtained oxide layers are characterized and discussed in nano- and microscopic scales.
The surface morphologies of the layers obtained have a significant influence on their properties, including their susceptibility
to further modification (e.g., to incorporation of graphite), their wear resistance, and the capacity for sorption of lubricants. 相似文献
9.
L. A. Trusov D. D. Zaitsev P. E. Kazin Yu. D. Tret’yakov M. Jansen 《Inorganic Materials》2009,45(6):689-693
Glasses with nominal compositions 11SrO · 5.5Fe2O3 · 4.5Al2O3 · 4B2O3 (1) and 15SrO · 5.5Fe2O3 · 4.5Al2O3 · 4B2O3 (2) were prepared by rapidly quenching oxide melts between counterrotating steel rollers. The glasses were then heat-treated in the range 650–950°C to produce glass-ceramic samples. The samples were characterized by X-ray diffraction, electron microscopy, and magnetic measurements. The phase composition of the glass-ceramics was determined, and their microstructure and magnetic properties were studied. The annealing temperature was shown to have a strong effect on the coercivity of the materials, which reaches 650 and 570 kA/m for compositions 1 and 2, respectively. 相似文献
10.
Gang Liu Huixia Wu Haoran Zheng Lihui Tang He Hu Hong Yang Shiping Yang 《Journal of Materials Science》2011,46(18):5959-5968
Bifunctional magnetic-luminescent dansylated Fe3O4@SiO2 (Fe3O4@SiO2-DNS) nanoparticles were fabricated by the nucleophilic substitution of dansyl chloride with primary amines of aminosilane-modified
Fe3O4@SiO2 core–shell nanostructures. The morphology and properties of the resultant Fe3O4@SiO2-DNS nanoparticles were investigated by transmission electron microscopy, FT–IR spectra, UV–vis spectra, photoluminescence
spectra, and vibrating sample magnetometry. The Fe3O4@SiO2-DNS nanocomposites exhibit superparamagnetic behavior at room temperature, and can emit strong green light under the excitation
of UV light. They show very low cytotoxicity against HeLa cells and negligible hemolysis activity. The T
2 relaxivity of Fe3O4@SiO2-DNS in water was determined to be 114.6 Fe mM−1 s−1. Magnetic resonance (MR) imaging analysis coupled with confocal microscopy shows that Fe3O4@SiO2-DNS can be uptaken by the cancer cells effectively. All these positive attributes make Fe3O4@SiO2-DNS a promising candidate for both MR and fluorescent imaging applications. 相似文献
11.
Soheil Sobhanardakani Raziyeh Zandipak 《Clean Technologies and Environmental Policy》2017,19(7):1913-1925
In the current study, SiO2/Fe3O4 core–shell nanoparticles functionalized with TiO2, using a simple method and application for removal of Cd(II), Hg(II) and Ni(II) ions from aqueous solution. The structure of the resulting product was confirmed by X-ray diffraction spectrometry, transmission electron microscopy (TEM), pHpzc and Brunauer, Emmett and Teller methods. The average diameter of TiO2/SiO2/Fe3O4 nanoparticles according to TEM was obtained around 48 nm. In batch tests, the effects of pH, initial metal concentration, contact time and temperature were studied. Adsorption of metal ions was studied from both kinetics and equilibrium point of view. Maximum adsorption capacity of Cd(II), Hg(II) and Ni(II) on TiO2/SiO2/Fe3O4 nanoparticles was 670.9, 745.6 and 563.0 mg g?1, respectively. Adsorption–desorption results showed that the reusability of nanoparticles was encouraging. This adsorbent was successfully applied to removal Cd(II), Hg(II) and Ni(II) ions in real samples including tap water, electronic wastewater and medical wastewater. 相似文献
12.
Mahuya Chakrabarti A. Banerjee D. Sanyal Manas Sutradhar Alok Chakrabarti 《Journal of Materials Science》2008,43(12):4175-4181
Fe2O3 of particle sizes ranging from 120 to 20 nm has been prepared by the ball-milling process using different milling hour. X-ray
diffraction technique and transmission electron microscopy have been used for determining the average particle sizes of the
prepared samples. Direct optical band gap for the unmilled and the ball-milled samples has been calculated from the optical
absorption data. A red shift in the band gap due to the reduction of particle size has been observed. The coincidence Doppler
broadening of the electron positron annihilation γ-radiation spectroscopy has been employed to identify the nature of defects
generated due to the ball-milling process. 相似文献
13.
M. Malligavathy S. Iyyapushpam S. T. Nishanthi D. Pathinettam Padiyan 《Journal of Materials Science: Materials in Electronics》2017,28(24):18307-18321
This paper demonstrates the preparation of pure TiO2, 40% of Bi2O3 in TiO2 and Ag loaded Bi2O3/TiO2 nanocomposites by the hydrothermal method followed by the photoreduction process. The crystal structure, morphology and composition of the samples were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy respectively. The dispersion of Ag nanoparticles on the surface of Bi2O3/TiO2 nanocomposites are found to bring the conduction band near to the valence band, resulting in the narrow band gap compared to pure TiO2 and Bi2O3/TiO2 nanocomposites. The XRD analysis demonstrated that silver nanoparticles were dispersed finely on the surface of Bi2O3/TiO2 nanocomposites. All the characterization results revealed that the Ag/Bi2O3/TiO2 nanocomposites were smaller crystallite size, stronger absorbance in the visible region and greater surface area than pure TiO2 and Bi2O3/TiO2 nanocomposites. The photoluminescence intensity decreases with an increase in the UV-illumination time of Ag loaded Bi2O3/TiO2 revealing a decrease in the recombination rate of electron–hole pairs. In order to test them as a photocatalyst, methyl orange was used as a standard. The photocatalytic degradation of methyl orange shows that the ABT5 sample exhibits the maximum degradation efficiency of 99% within 180 min of irradiation. 相似文献
14.
A series of glass comprising of SiO2–MgO–B2O3–Y2O3–Al2O3 in different mole ratio has been synthesized. The crystallization kinetics of these glasses was investigated using various
characterization techniques such as differential thermal analysis (DTA), thermo gravimetric analysis (TGA), X-ray diffraction
(XRD), and scanning electron microscopy (SEM). Crystallization behavior of these glasses was markedly influenced by the addition
of Y2O3 instead of Al2O3. Addition of Y2O3 increases the transition temperature, T
g, crystallization temperature, T
c and stability of the glasses. Also, it suppresses the formation of cordierite phase, which is very prominent and detrimental
in MgO-based glasses. The results are discussed on the basis of the structural and chemical role of Y3+ and Al3+ ions in the present glasses. 相似文献
15.
Qi Liu Lifang Lai Xiujuan Fu Fangping Zhu Jianhua Sun Hongren Rong Mingyang He Qun Chen Zheng Xu 《Journal of Materials Science》2007,42(24):10113-10117
Hollow CoFe2O4 spheres consisted of CoFe2O4 nanoparticles were synthesized by a facile solvothermal treatment of an ethylene glycol solution of FeCl3 · 6H2O, CoCl2 · 6H2O, and NaAc at 200 °C in the presence of polyethylene glycol and oleic acid. The products were characterized by powder X-ray
diffraction, transmission electron microscopy, selected area electron diffraction, high-resolution transmission microscopy,
scanning electron microscopy. The magnetic properties were evaluated using a vibrating sample magnetometer. The probable mechanism
of the formation of Hollow CoFe2O4 spheres was discussed.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
16.
D. A. Balaev S. S. Yakushkin A. A. Dubrovskii G. A. Bukhtiyarova K. A. Shaikhutdinov O. N. Martyanov 《Technical Physics Letters》2016,42(4):347-350
We report the results of investigations of ε-Fe2O3 magnetic nanoparticles obtained by incipient wetness impregnation of silica gel. It was established that the obtained samples with an iron content of 12?16% mass % containing ε-Fe2O3 nanoparticles with an average size of 10 nm on the silica gel surface exhibit a room-temperature coercivity of about 10 kOe. Along with fabrication simplicity, this fact makes the prepared samples promising for application as a magnetically hard material. 相似文献
17.
Menaka Mohammed Qamar Samuel E. Lofland Kandalam V. Ramanujachary Ashok K. Ganguli 《Bulletin of Materials Science》2009,32(3):231-237
The present study describes the synthesis of ZnMn2O4 nanoparticles with the spinel structure. These oxide nanoparticles are obtained from the decomposition of metal oxalate precursors
synthesized by (a) the reverse micellar and (b) the coprecipitation methods. Our studies reveal that the shape, size and morphology
of precursors and oxides vary significantly with the method of synthesis. The oxalate precursors prepared from the reverse
micellar synthesis method were in the form of rods (micron size), whereas the coprecipitation method led to spherical nanoparticles
of size, 40–50 nm. Decomposition of oxalate precursors at low temperature (∼ 450°C) yielded phase pure ZnMn2O4 nanoparticles. The size of the nanoparticles of ZnMn2O4 obtained from reverse micellar method is relatively much smaller (20–30 nm) as compared to those made by the co-precipitation
(40–50 nm) method. Magnetic studies of nanocrystalline ZnMn2O4 confirm antiferro-magnetic ordering in the broad range of ∼ 150 K. The photocatalytic activity of ZnMn2O4 nanoparticles was evaluated using photo-oxidation of methyl orange dye under UV illumination and compared with nanocrystalline
TiO2.
Dedicated to Prof. C N R Rao on his 75th birthday 相似文献
18.
Polypyrrole (PPY)/Co3O4 nanocomposites (NCs) were synthesized by a facile in situ polymerization of pyrrole in the presence of Co3O4 nanoparticles which were obtained by a rheological phase reaction method. The structure and morphology of the as-prepared
PPY/Co3O4 NCs were investigated by X-ray diffraction, Fourier transform infrared spectra, Raman spectra, scanning electron microscopy
and transmission electron microscopy, which confirmed the formation of the nanocomposites and indicated some interactions
between PPY chains and Co3O4 nanoparticles. Different PPY/Co3O4 ratios were selected in order to study conductive properties. The electrical conductivity measurements indicated that ac
conductivity tended to remain constant up to about 107 Hz for all samples, and thereafter increased with frequency. The desired electrical properties of PPY/Co3O4 NCs can be modulated simply by controlling the contents of Co3O4 nanoparticles. 相似文献
19.
M. Markova-Velichkova R. Iordanova A. Stoyanova Y. Dimitriev D. Klissurski 《Journal of Materials Science》2007,42(10):3383-3387
Melt quenching technique was applied to study tendency for phase formation and amorphization in the MoO3–ZrO2–V2O5 system. By X-ray diffraction were detected the main crystalline phases separated during the quenching: Zr(MoO4)2, V2MoO8, (Mo0.3V0.7)2O5, V0.95Mo0.97O5 but in a wide concentration range the dominant crystalline phase was monoclinic ZrO2. The average particle sizes of the obtained crystal phases were in the range 30–50 nm. A narrow glass formation area was
situated, near MoO3–V2O5 side. The glass-crystalline samples were obtained in the MoO3- and V2O5-rich compositions. The phase formation was proven by IR analysis also. IR data showed that the main structural units built
up the glass network are corner shared VO5 and MoO6 groups while in the corresponding crystal V2MoO8 phase MeO6 (Me = V, Mo) octahedra are corner and edge shared (band at 580 cm−1). 相似文献
20.
The formation and the thickness growth of the (Bi,Pb)2Sr2Ca2Cu3O10 phase in Ag-sheathed tapes have been investigated by scanning electron microscopy on samples sintered at 840°C in a flow
of 8.5% O2 (rest N2) and quenched in air after sintering for 1 to 50 h. The thickness of the (Bi,Pb)2Sr2Ca2Cu3O10 grains was measured statistically after different sintering times. The experimental results show that the average thickness
of these grains increases during the entire sintering period, while the average thickness growth rate decreases exponentially
with sintering time. The volume fractions of the various phases present during the heat treatment were also measured from
micrographs. Detailed studies of the microstructure and phase formation kinetics support the view that the formation of the
(Bi,Pb)2Sr2Ca2Cu3O10 phase proceeds via a nucleation and growth process. Based on the present observations, a model describing the microstructure
evolution is presented. 相似文献