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1.
《Materials Research Bulletin》2004,39(4-5):669-676
A new solvothermal route for the preparation of nanocrystals of PbS and PbSe, involving the reaction of lead stearate with sulfur or selenium and tetralin (tetrahydronaphthalene) in toluene solvent is described. Tetralin in the presence of S/Se gives H2S/H2Se and gets aromatized to naphthalene. The nanocrystals have been characterized by powder X-ray diffraction and electron microscopy. Use of surfactant Triton X-100 (polyoxyethylene(10)isooctylphenyl ether) resulted in both nanorods and nanoparticles of PbSe. Capping by citric acid and malonic acid reduce the particle sizes to less than 10 nm. 相似文献
2.
In this work, immobilizing a series of ionic liquids (ILs) 1-alkyl-3-methylimidazolium chloride [C
n
mim]Cl (n = 2, 4, 6, 8) on the layered zirconium phosphates were investigated. [C4mim]Cl was used to explore in detail the factors affecting intercalation. By comparing several starting materials including
α-zirconium phosphate (α-ZrP), γ-zirconium phosphate (γ-ZrP) and the corresponding alkylamine preintercalated composites,
it was found that the α-ZrP · 2BA (i.e., preintercalated BA were arranged in a bilayer mode at the galleries of α-ZrP) was
a suitable host for intercalating ILs. Intercalation was verified with X-ray diffraction (XRD), Raman, UV–Vis and other instrumental
approaches. pH effect on immobilization was investigated. Other ionic liquids including [C
n
mim]Cl (n = 2, 6, 8) intercalation compounds were prepared. Based on XRD data, the interlayer distances of the studied intercalation
compounds were similar, suggesting that the ionic liquids were arranged in an approximately planar manner, as confirmed by
molecular modeling. 相似文献
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5.
《Materials Letters》2006,60(25-26):3175-3178
A new esterification reaction under solvothermal conditions was first applied to synthesize CoO nanoparticles in this paper. Esterification reaction of cobalt acetate and anhydrous ethanol under solvothermal conditions results in the formation of CoO nanoparticles. The concentrations of cobalt acetate, reaction temperature and surfactant to as-synthesized CoO have been explored. SEM, TEM and XRD were employed to characterize the size, morphology and crystalline structure of the as-synthesized CoO nanoparticles. It is revealed that the FCC-structured CoO nanoparticles are of uniform tetragonal projected shape with good dispersion. Typically, CoO nanoparticles with an average size of 35 nm were obtained at 150 °C for 24 h using 0.08 mol/L solution of Co(CH3COO)2·4H2O in ethanol under solvothermal conditions. 相似文献
6.
P. Srikari Tantri K. Geetha A. M. Umarji Sheela K. Ramasesha 《Bulletin of Materials Science》2000,23(6):491-494
Ba1.5-xSrxZr4P5SiO24 compounds withx = 0, 0.25, 0.5, 0.75, 1.0, 1.25 and 1.5, belonging to the low thermal expansion NZP family were synthesized by the solid
state reaction method. The XRD pattern could be completely indexed with respect to
space group indicating the ordering of vacancy at the divalent cation octahedral sites. The microstructure and bulk thermal
expansion coefficient from room temperature to 800°C of the sintered samples have been studied. All the samples show very
low coefficient of thermal expansion (CTE), withx = 0 samples showing negative expansion. A small substitution of strontium in the pure barium compound changes the sign of
CTE. Similarly,x = 1.5 sample (pure strontium) shows a positive CTE and a small substitution of barium changes its sign.X = 1.0 and 1.25 samples have almost constant CTE over the entire temperature range. The low thermal expansion of these samples
can be attributed to the ordering of the ions in the crystal structure of these materials 相似文献
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9.
Motoaki Adachi Kikuo Okuyama Seongwon Moon Noboru Tohge Yasuo Kousaka 《Journal of Materials Science》1989,24(6):2275-2280
Ultrafine zirconia particles are produced by thermal decomposition of zirconium tetratertiary butoxide (ZrTB) vapour. The
introduction of ZrTB vapour into the cylindrical electric furnace, is achieved by three different methods: (evaporator, pressurized
nebulizer and ultrasonic nebulizer). The properties of the fine particles obtained by these methods are mainly analysed by
X-ray diffraction and transmission electron microscopy. It is found that ultrafine zirconia particles produced at relatively
low temperatures from 600 to 700° C are spherical in the diameter range 0.035 to 0.15 μm and of tetragonal phase. Furthermore,
two-component fine particles of zirconia-ilver are generated by putting the silver solid inside the furnace containing alkoxide
vapour, and are deposited by inertia on to a glass substrate under low pressure to form films having a thickness of 17 to
33 μm. The electrical characteristics of the films are evaluated, and the conductance of the film is found to increase with
the content of the silver component. 相似文献
10.
Wenxing Zhang Lixin Cao WenWen Wang Ge Su Wei Liu 《Journal of Materials Science: Materials in Electronics》2013,24(7):2234-2239
(Ba0.8Sr0.2ZryTi1?yO3) (y = 0.05, 0.1, 0.15 and 0.2) nanosized powders is synthesized by solvothermal method. The formation of (Ba0.8Sr0.2ZryTi1?yO3) was confirmed by XRD, FT-IR and XPS analysis. The purity of the (Ba0.8Sr0.2ZryTi1?yO3) was examined using FT-IR spectroscopy. The X-ray analysis proves that all as-synthesized Ba0.8Sr0.2ZryTi1?yO3 powders have a cubic perovskite structure. The surface characterization indicates the powder contains Zr and Sr elements. SEM investigation shows that the average particle size is reduced with increasing the Zr content and the average particle size is in the range 37–50 nm, the well dispersed nano powders have narrow particle size distribution. The study of dielectric properties shows that the Curie peaks of dielectric constant become broader and shift towards lower temperature on the basis of Ba0.8Sr0.2TiO3 and the dielectric loss decreases with increasing Zr content. 相似文献
11.
V. A. Sadykov Svetlana N. Pavlova Galina V. Zabolotnaya Raisa I. Maximovskaya Sergei V. Tsybulya Elena B. Burgina Vladimir I. Zaikovskii Galina S. Litvak Marina V. Chaikina Valerii V. Lunin Natalya N. Kuznetsova Rustum Roy Dinesh K. Agrawal 《Materials Research Innovations》1999,2(6):328-337
High-power ball mill activation of the mixture of hydrated zirconium and lanthanum salts (oxonitrates, oxochlorides) with
ammonium phosphate followed by hydrothermal treatment at temperatures not exceeding 200°C and a nearly neutral pH was found
to yield crystalline dispersed phase of a cubic NH4Zr2(PO4)3 type along with admixtures of disordered orthorhombic compounds of a zirconium orthophosphate type. In the same conditions
and at the same Zr/P ratio, hydrothermal treatment of gels obtained by reacting mixed zirconium and lanthanum nitrates solutions
with ammonium phosphates yields no crystalline products, and only treatment in acid media generates a phase of the α-ZrPO4(OH) type coexisting with the NH4Zr2(PO4)3 phase if polyethylene oxide is present. X-ray powder diffraction, transmission electron microscopy, 31MAS-NMR, FTIRS and thermal analysis were applied to elucidate factors affecting crystallization of complex zirconium phosphates
in the hydrothermal conditions. The most essential factor appears to be generation of some nuclei of zirconium phosphates
under high pressures developed in the course of mixed solids mechanical activation. These nuclei are embedded into matrix
of such well-crystallized solid products as ammonium nitrate or chloride. Hence, metastable cubic or orthorhombic structure
of the phases obtained via mechanical activation route can be assigned to the nuclei-matrix orientation relationship. Due
to easily scaled-up synthesis procedure, these results appear to be very promising for manufacturing of dispersed framework
zirconium phosphates as acid catalysts or fast proton conductors.
Received: 18 November 1998 / Reviewed and accepted: 2 December 1998 相似文献
12.
C. Collado G. GoglioG. Demazeau A.S. BarrièreL. Hirsch M. Leroux 《Materials Research Bulletin》2002,37(5):841-848
GaN microcrystallites have been prepared by a solvothermal process. The influence of the synthesis temperature on the crystallinity of the resulting GaN has been studied on three samples, prepared at 400, 600 and 800°C in the same pressure conditions (150 MPa) and duration (6 h). The resulting powders were characterized by several techniques: X-ray diffraction to evaluate the reaction rate, scanning electron microscopy (SEM) to determine the morphology and size of the microcrystallites and photoluminescence to evaluate the quality of the powders. 相似文献
13.
Recycling of fiber reinforced plastics using depolymerization by solvothermal reaction with catalyst
Tomoko Iwaya Shinpei Tokuno Mitsuru Sasaki Motonobu Goto Katsuji Shibata 《Journal of Materials Science》2008,43(7):2452-2456
Fiber reinforced plastics (FRP) have been widely used as a high strength material. However, it is well known that the FRP
is one of the most difficult materials to fractionate into elemental components, namely fiber, filler, and polymers in the
waste recycling process. Therefore, the wastes are treated in the incineration or landfilling without any recycling approaches.
We have developed a new recycling method using subcritical fluids where unsaturated polyester (UP) resin in FRP can be efficiently
depolymerized to separate glass fiber from filler and polymer. Reactions were carried out with or without a catalyst (K3PO4) in diethyleneglycol monomethylethter (DGMM) and benzyl alcohol under their subcritical state at temperatures 463–623 K for
1–8 h in a batch reactor. The conversion of UP became fast as the catalyst/solvent molar ratio increased and it was enhanced
in the presence of K3PO4 catalyst in subcritical BZA. The glass fiber recovered after the FRP treatment in subcritical BZA was relatively long, while
it became short and somewhat damaged at temperature higher than 573 K. The similar trend was observed when DGMM was used as
a solvent. 相似文献
14.
Shu Yin Shingo Akita Makoto Shinozaki Ruixing Li Tsugio Sato 《Journal of Materials Science》2008,43(7):2234-2239
Eu doped Y2O3 and some kinds of other rare earth oxides nanoparticles such as Er2O3, Nd2O3, Ho2O3, Lu2O3, and Dy2O3 were prepared by a simple co-precipitation-solvothermal treatment-calcination process, where the co-precipitated amorphous
hydroxide precursors obtained by adding rare earth nitrate solutions in ammonia solutions were heated in solvents such as
water, alcohols and glycols, followed by calcination in air. The morphology of rare earth oxide particles strongly depended
on the solvothermal reaction medium but not related to the kind of rare earth oxide. The powders prepared in water and ethanol
possessed nanowire structure, where the aspect ratio of powder treated in water was higher than that in ethanol. The powders
prepared by co-precipition-solvothermal treatment-calcination process using ethylene glycol consisted of near-spherical nanoparticles
whereas that prepared by conventional co-precipitation-calcination method consisted of hardly agglomerated submicron particles.
The nanoparticles of Eu3+ doped Y2O3 prepared by co-precipition-solvothermal treatment-calcination process showed similar intensity of photoluminescence with
the submicron particles by co-precipition-calcination process. 相似文献
15.
LiOH·H2O, Co(NO3)2·6H2O and NH4VO3 were used to prepare nano-crystalline LiCoVO4 by 150 °C solvothermal reaction in isopropanol for 10–360 h and subsequent calcination at 300–500 °C for 6 h. XRD, TEM and selected area electron diffraction (SAED) revealed the presence of nano-crystalline LiCoVO4 with inverse spinel structure. The V–O stretching vibration modes of VO4 tetrahedrons were detected by FTIR over the range 617–835 cm− 1 and by Raman spectrometer at 805.7 and 783.1 cm− 1. Co, V and O were detected by EDX. TGA of solvothermal products shows weight loss due to the evaporation and decomposition processes at 40–648 °C. 相似文献
16.
Spherical basic zirconium sulphate particles were prepared by homogeneous precipitation in mixed solutions of zirconium sulphate and urea. Values of [SO
4
2–
]/[Zr4+] and [urea]/[Zr4+] in starting mixed solutions and cooling rate may affect the formation of spherical particles. Complexes such as [Zr(OH)n]4–n could prevent the formation and thus lead to gel precipitation. In addition, spherical particles could only be obtained in the presence of SO
4
2–
; for NO3– and Cl–, only gel precipitation occurred. 相似文献
17.
AgBiS2 nanostructured flowers were produced from CH3COOAg, Bi(NO3)3.5H2O and thiosemicarbazide (NH2CSNHNH2) using different solvents [ethylene glycol (EG), water (H2O), polyethylene glycol with molecular weight of 200 (PEG200), and propylene glycol (PG)] in Teflon-lined stainless steel autoclaves. The phase and purity were detected using X-ray diffraction (XRD), controlled by the solvents. The product was purified AgBiS2 produced by the 200 °C and 24 h reaction in EG, corresponding to selected area electron diffraction (SAED) and simulation patterns. Scanning and transmission electron microscopies (SEM and TEM) revealed the formation of nanostructured flowers — enlarged by the increase in the lengths of time and temperature. Their photoluminescence (PL) emissions were detected at the same wavelength of 382 nm (3.24 eV), although they were produced under different conditions. 相似文献
18.
Satoshi Wada A. Nozawa M. Ohno H. Kakemoto T. Tsurumi Y. Kameshima Y. Ohba 《Journal of Materials Science》2009,44(19):5161-5166
Barium titanate (BaTiO3) nanocube particles below 20 nm were prepared by solvothermal method. A selection of organic solvent and inorganic materials
of Ba and Ti sources was most important for the preparation of nanocubes. A nucleation and particle growth of BaTiO3 nanoparticles led to a formation of the BaTiO3 nanocubes with a size of 10–15 nm at temperatures above 200 °C. 相似文献
19.
A. I. Orlova D. V. Kemenov S. G. Samoilov G. N. Kazantsev V. I. Pet’kov 《Inorganic Materials》2000,36(8):830-834
The thermal expansion of the A
x
Zr2.25-0.25x(PO4)3 phosphates with A = Na(x = 0.5,1.0,2.0,3.0,4.0, 5.0) and K(x = 1.0, 3.0, 5.0), crystallizing in structures of the NaZr2(PO4)3 type (sp. gr.R3c or C2/c), was studied by high-temperature x-ray powder diffraction in the range 20–700‡C. The lattice parametersa and c and thea- andc-axis thermal expansion coefficients (αa and αc) were determined. The thermal expansion of the phosphates was found to be highly anisotropic (αa < 0, αc > 0). The strongest anisotropy was found in NaZr2(PO4)3 (αa = -4.89 x 10-6 K-1, αc = 22.02 x 10-6 K-1), KZr2(PO4)3 (αa =-5.30 x 10-6 K-1, αc = 5.41 x 10-6 K-1), and Na5Zr(PO4)3 (αa = -5.82 x 10-6 K-1, αc
= 20.73 x 10-6 K-1). K5Zr(PO4)3 exhibited the smallest thermal expansion and weak anisotropy (αa = -2.14 x 10-6 K-1, αc = 2.65 x 10-6 K-1). The effects of M(l) and M(2) site occupancies on αa, αc,a, and c were assessed. The relative magnitudes of crystal-chemical and thermal expansion in the Na and K compounds were analyzed. 相似文献
20.
Thermal expansion behaviour of sodium zirconium phosphate structure type phosphates of the formula AM3+SnP3O12 (A=Ca, Sr and Ba; M3+=Cr and Fe) was studied by high temperature X-ray diffraction and dilatometry in the temperature range 298-1073 K. The variation in the hexagonal lattice parameters of the Ca-containing compounds is in line with the ‘sodium zirconium phosphate behaviour’. However, the strontium- and barium-containing compounds display an altogether different behaviour of axial expansion. The results are explained based on the crystal chemistry of these compounds. 相似文献