Low-temperature chemical synthesis of nanocrystalline KTiOPO4

2002 ◽  
Vol 17 (4) ◽  
pp. 723-726 ◽  
Author(s):  
Donglin Lia ◽  
Zhihong Wang ◽  
Liangying Zhang ◽  
Xi Yao ◽  
Haoshen Zhou
Keyword(s):  
Chemical Process ◽  
Average Particle Size ◽  
Homogeneous Solution ◽  
Amorphous Powder ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Partial Evaporation ◽  
Hydrolysis Of

Nanocrystalline KTiOPO4 powders were prepared through a chemical process. This process involved the hydrolysis of KOOCCH3 · 2H2O, Ti(OC4H9)4, and PO(OR)3 to produce a homogeneous solution. A gel was formed by the partial evaporation of this solution. After the gel was decomposed at 450 °C, white amorphous powder remained. On calcinating up to 550 °C, the amorphous powder began to transform into nanocrystalline KTiOPO4 powders with an average particle size of 30–50 nm. The KTiOPO4 powders were investigated through x-ray diffraction, infrared spectroscopy, and transmission electron microscopy studies.

DIELECTRIC PROPERTIES OF ULTRAFINE Zn-DOPED CaCu3Ti4O12 CERAMIC

2012 ◽  
Vol 02 (01) ◽  
pp. 1250007 ◽  
Author(s):  
LAXMAN SINGH ◽  
U. S. RAI ◽  
K. D. MANDAL ◽  
MADHU YASHPAL
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Room Temperature ◽  
Single Phase ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Sintered Powder

Ultrafine powder of CaCu2.80Zn0.20Ti4O12 ceramic was prepared using a novel semi-wet method. DTA/TG analysis of dry powder gives pre-information about formation of final product around 800°C. The formation of single phase was confirmed by X-ray diffraction analysis. The average particle size of sintered powder of the ceramic obtained from XRD and Transmission electron microscopy was found 59 nm and 102 nm, respectively. Energy Dispersive X-ray studies confirm the stoichiometry of the synthesized ceramic. Dielectric constant of the ceramic was found to be 2617 at room temperature at 1 kHz.

Investigation on Carbonizing Behaviors of Nanometer-sized Cr2O3 Particles Dispersed on Alumina Particles by Metalorganic Chemical Vapor Deposition in Fluidized Bed

2005 ◽  
Vol 20 (8) ◽  
pp. 2154-2160 ◽  
Author(s):  
Hao-Tung Lin ◽  
Jow-Lay Huang ◽  
Wen-Tse Lo ◽  
Wen-Cheng J. Wei
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Graphite Furnace ◽  
Average Particle Size ◽  
Chemical Vapor ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Alumina Particles

Nanoscaled Cr2O3 powder with an average particle size of 20–40 nm, coated on alumina particles, has been produced by means of chemical vapor deposition (CVD) in a fluidized chamber, using the pyrolysis of Cr(CO)6 precursor. Amorphous and crystalline Cr2O3 particles were obtained when the temperatures of the pyrolysis were 300 and 400 °C, respectively. To prepare nanoscaled Cr3C2 powder from the nanometer-sized Cr2O3, carbonizing behavior of the Cr2O3 particles was investigated. It was found that, when amorphous Cr2O3 powders were carbonized in graphite furnace at 1150 °C for 2 h in vacuum (10−3 Torr), the powder was transformed into Cr3C2, while the crystalline Cr2O3 was transformed into a mixture of Cr7C3 and Cr3C2. The examinations by x-ray diffraction, transmission electron microscopy, and energy dispersive spectroscopy confirmed the transformation of the nano-sized Cr3C2 powders. The results of thermogravimetry and differential thermal analysis indicated that the transformation temperature was ∼1089 °C for amorphous Cr2O3 and ∼1128 °C for crystalline Cr2O3.

The concentration quenching of photoluminescence in Eu3+-doped La2O3

2013 ◽  
Vol 37 (1) ◽  
pp. 47-54 ◽  
Author(s):  
V. Đorđević ◽  
Ž. Antić ◽  
M. G. Nikolić ◽  
M. D. Dramićanin
Keyword(s):  
Room Temperature ◽  
Hexagonal Phase ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Maximum Lifetime ◽  
Transmission Electron ◽  
Lifetime Value ◽  
Kinetics Of

Abstract This work explores the influence of dopant concentration on photoluminescent emission and kinetics of Eu3+-doped (0.2−10 at.%) nanocrystalline lanthanumoxide powders. The X-ray diffraction analysis confirmed that all samples crystallize in La2O3 hexagonal phase with space group P3¯ m1. Transmission electron microscopy showed particles with non-uniform shape and diverse size distribution with an average particle size of (95 ± 5) nm. The room temperature photoluminescence spectra of all samples contain characteristic Eu3+ luminescence lines with the most pronounced red 5D0 →7F2 emission at about 626 nm. The maximum intensity of red emission is observed for the sample containing 5at.% of Eu3+ ions. The emission kinetics was recorded in the temperature range from 10K to 300 K. The maximum lifetime value of 0.98 ms obtained for the sample with 0.5at.% Eu3+ at room temperature increases up to 1.3ms at 10 K.

scholarly journals Synthesis and Characterization of Cu2FeSnSe4 Nanofilms

2021 ◽  
pp. 1873-1878
Author(s):  
Omar Abdulsada Ali ◽  
Sarmed S.M. Al-Awadi
Keyword(s):  
Electron Microscopy ◽  
Average Particle Size ◽  
Average Particle ◽  
Electrochemical Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Photovoltaic Applications ◽  
Tem Transmission Electron Microscopy

Well dispersed Cu2FeSnSe4 (CFTSe) nanofilms were synthesized by hot-injection method. The structural and morphological measurements were characterized using XRD (X-ray diffraction), Raman spectroscopy, SEM (scanning electron microscopy), and TEM (transmission electron microscopy). Chemical composition and optical properties of as-synthesized CFTSe nanoparticles were characterized using EDS (energy dispersive spectroscopy) and UV-Vis spectrophotometry. The average particle size of the nanoparticles was about 7-10 nm. The UV-Vis absorption spectra showed that the synthesized CFTS nanofilms have a band gap (Eg) of about 1.16 eV. Photo-electrochemical characteristics of CFTSe nanoparticles were studied and indicated their potential application in photovoltaic applications.

IMPACT OF SURFACTANTS ON PHYSICAL PROPERTIES OF BaTiO3 NANOPARTICLES

2013 ◽  
Vol 12 (01) ◽  
pp. 1350003 ◽  
Author(s):  
R. VIJAYALAKSHMI ◽  
V. RAJENDRAN
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Average Particle Size ◽  
Ammonium Bromide ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Nanocrystalline BaTiO3 particles of about 20–35 nm have been successfully synthesized by using cationic, anionic and nonionic surfactants such as cetyltrimethyl ammonium bromide (CTAB), sodium dodecyl sulphate (SDS) and poly ethylene glycol (PEG) via hydrothermal method. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis absorption spectroscopy and photoluminescence (PL) spectroscopy. The average particle size, measured by powder X-ray diffraction was determined to be 20–35 nm and was confirmed by transmission electron microscopy. Spherical-like morphologies were obtained by scanning electron microscopy (SEM) analysis. Optical properties of products were investigated by ultraviolet-visible (UV-Vis) absorption and PL spectroscopies.

A powder x-ray diffraction study of a solution treated and ice brine quenched Al–14.25 at.% Li alloy

1991 ◽  
Vol 6 (4) ◽  
pp. 712-718 ◽  
Author(s):  
A.G. Fox ◽  
S.C. Fuller ◽  
C.E. Whitman ◽  
V. Radmilovic
Keyword(s):  
Particle Size ◽  
Volume Fraction ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Maximum Order ◽  
X Ray ◽  
Order And Disorder ◽  
Solution Treated ◽  
Transmission Electron

An x-ray diffractogram was generated from a powder sample of solution treated and ice brine quenched Al–14.25 at.% Li alloy. The Bragg reflections obtained were characteristic of a very-nearly fully ordered Al-rich L12 phase based on δ'Al3Li together with two very weak reflections associated with δAlLi. All the lines were significantly broadened due to particle size effects. The average particle size associated with the 100 L12 superlattice line was found to be 4.2 (3) nm and with the fundamental lines, 26.8 nm. A simple structure factor calculation indicated the volume fraction of ordered phase to be around 0.77, assuming that the lack of maximum order was due to the presence of disordered fcc AlLi solid solution. These results suggest that the microstructure of this as-quenched alloy comprises ordered regions of about 4 nm in size in a sea of disordered matrix with a very small amount of δAlLi present. This conclusion is in excellent agreement with recent small angle x-ray and transmission electron microscope studies on similar alloys and suggests that AlLi alloys which are ostensibly disordered at high temperatures go through a disorder-order transformation and then decompose into regions of order and disorder which are associated with a composition spinodal.

scholarly journals Structure and Optical Property of Gold Nanoparticles Synthesized by Modified Polyol Method

2021 ◽  
Vol 31 (3) ◽  
Author(s):  
Long Nguyen Viet
Keyword(s):  
Gold Nanoparticles ◽  
Au Nanoparticles ◽  
Average Particle Size ◽  
Nir Spectroscopy ◽  
Polyol Method ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Modified Polyol Method

In this research, Au nanoparticles were successfully synthesized by modified polyol method with commercial precursors to be gold (III) chloride trihydrate (HAuCl4·3H2O), ethylene glycol (EG), poly(vinylpyrrolidone) (PVP), sodium borohydride (NaBH4). The structure and properties of as-prepared Au nanoparticles have been investigated by X ray diffraction (XRD), transmission electron microscopy (TEM), and UV-vis-NIR spectroscopy. As a result, Au nanoparticles with the average particle size of 28.80 nm were successfully synthesized in the range of about 50 nm. It is evidenced that the assembly of gold nanoparticles was presented in their nucleation, growth, and formation. 

Synthesis and Characterization of Strontium and Calcium Titanate Polycrystalline Powders by a Modified Polymeric Precursor Technique

2012 ◽  
Vol 727-728 ◽  
pp. 904-908
Author(s):  
R. Muccillo ◽  
J.R. Carmo
Keyword(s):  
Particle Size ◽  
Structural Phase ◽  
Average Particle Size ◽  
Calcium Titanate ◽  
Average Particle ◽  
Polymeric Precursor ◽  
X Ray Diffraction ◽  
Laser Scattering ◽  
X Ray ◽  
Transmission Electron

SrTi0,65Fe0,35O3-δ, Ca0,5Sr0,5Ti0,65Fe0,35O3-δ, CaTi0,65Fe0,35O3-δceramic powders were synthesized by the polymeric precursor technique using CaCO3, SrCO3, C12H28O4Ti and Fe (NO3)3.9H2O. After calcination, each powder was heat treated at temperatures chosen according to data collected on thermogravimetric-differential thermal analysis experiments. The compositions were analyzed by X-ray diffraction for structural phase evaluation (either perovskite cubic or orthorhombic), laser scattering for determination of particle size distribution and average particle size, transmission electron microscopy (TEM) for observation of particle shape and average true size. Pressed powders sintered at 1250°C were analyzed by X-ray diffraction and X-ray fluorescence; their surfaces were observed by scanning probe microscopy (SPM) for topographical analysis of grains and grain boundaries. TEM results show that the powders consist of agglomerated nanoparticles. Sr-based compounds have cubic perovskite phases whereas Ca-based compounds are orthorhombic. SPM images show intergranular features which might be responsible for reported blocking of charge carriers observed in impedance spectroscopy diagrams.

Mn and MnZn Ferrite Powders Prepared by Detonation of Emulsion Explosives

2011 ◽  
Vol 694 ◽  
pp. 630-634
Author(s):  
Xiao Jie Li ◽  
Xiao Hong Wang ◽  
Hong Hao Yan ◽  
Li Xue ◽  
Ning Luo
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Residual Magnetization ◽  
Average Particle ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
Emulsion Explosives ◽  
Mnzn Ferrite ◽  
X Ray ◽  
Transmission Electron

In the present work, nano Mn and MnZn ferrite powders were prepared by detonation of emulsion explosives, XRD(X-ray diffraction),TEM(transmission electron microscope) and VSM(vibrating sample magnetometer) experiments were carried out respectively to characterize and research the prepared powders. Results indicated that the average particle size of the raw Mn and MnZn ferrite powders was around 30nm, and Zn2+ seriously destroyed and reduced the dispersity and homogeneity of the powders although they were successfully doped in nano-Mn ferrite crystals. The average particle size, the specific residual magnetization(σr) and the coercivity(Hc) of the powders were all decreased with the increasing of the hexogen(for short, RDX) content.

ELECTROCHEMICAL SYNTHESIS AND CHARACTERIZATION OF DIFFERENT MORPHOLOGIES NANORAMSDELLITE-MnO2

NANO ◽  
2012 ◽  
Vol 07 (04) ◽  
pp. 1250030
Author(s):  
MADJID TORKAMAN ◽  
AZIZAN AZIZ ◽  
MOHAMAD ABU BAKAR ◽  
SULAIMAN AB GHANI
Keyword(s):  
Electron Microscopy ◽  
Reaction Time ◽  
Average Particle Size ◽  
Reaction Times ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Crystal Particle

In this work manganese dioxide (Ramsdellite- MnO2 ) was synthesized at room temperature using a facile electrochemical method. X-ray diffraction (XRD) was used to identify the type and the size of the crystal particle, while field emission scanning electron microscopy (FESEM) and energy filtered transmission electron microscopy (EFTEM) were used to show and identify the morphology of the particles and changes of their morphologies with the increase of reaction times. Fourier transform infrared (FTIR) spectroscopy confirmed the Mn–O bond. Results from XRD showed that optimum time for synthesis Ramsdellite- MnO2 was 9 h. The results of EFTEM showed a mixture of nanospheres and nanorods after 9 h reaction time while a homogenous morphology of nanospheres was detected at 12 h reaction time. Results confirmed on the existence of a correlation between the reaction time and the resulting nanostructures. Moreover, the EFTEM result showed that average particle size for 12 h was (25 ± 7 nm). The variation of calculated specific capacitance (F/g) versus the different scan rate has indicated that the efficiency of synthesized Ramsdellite- MnO2 nanostructures in 12 h reaction time was superior to 9 h.

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