scholarly journals Process for Producing Nano-Alpha-Alumina Powder

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Fatemeh Mirjalili ◽  
Luqman Chuah Abdullah ◽  
Hasmaliza Mohamad ◽  
A. Fakhru'l-Razi ◽  
A. B. Dayang Radiah ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Sol Gel ◽  
Alumina Nanoparticles ◽  
Alumina Powder ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Stirring Time ◽  
Particle Size And Shape

This paper is trying to explore the effect of stirring time on the synthesis of nano-α-Alumina particles. In this study, alumina nanoparticles were synthesized through alkoxide route using sol-gel method, where aqueous solutions of aluminum isopropoxide and 0.5 M aluminum nitrate nanohydrate were used for preparing alumina sol. Sodium dodecylbenzen sulfonate (SDBS) was used as the surfactant stabilizing agent. The prepared solution was stirred at different times (24, 36, 48, and 60 hours) at 60°C. The Samples were, then, characterized by X-ray diffraction, thermogravimetry analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and Transmission Electron Microscopy(TEM) . The introduction of different stirring times affected the particle size and shape and the degree of aggregation. By increasing the stirring time, (starting from 24 to 48 hours) the particle size decreased, but agglomeration became hard for 60 hours of stirring time. The finest particle size (20–30 nm) was obtained at 48-hour stirring time.

Solid State Amorphization of Ti60Si40 Alloy via Mechanical Alloying

2021 ◽  
Vol 876 ◽  
pp. 7-12
Author(s):  
Petr Urban ◽  
Fátima Ternero Fernández ◽  
Rosa M. Aranda Louvier ◽  
Raquel Astacio López ◽  
Jesus Cintas Físico
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Mechanical Alloying ◽  
Amorphous Phase ◽  
Milling Time ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Heating Up

The effect of milling time on the microstructure evolution and formation of amorphous phase of Ti60Si40 alloy produced by mechanical alloying (MA) has been investigated. Laser diffraction, Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and Differential Scanning Calorimetry (DSC) were employed to characterize the particle size, morphology and structure of mechanically alloyed Ti60Si40. When the milling time is increased to 20 h, the particle size decreases from 23.7 to 4.7 μm, the shape of the particles changes to spherical and the crystalline structure is transformed into an amorphous phase. The amorphous Ti60Si40 alloy is stable when heating up to 750oC. Above this temperature, the cold crystallization of the intermetallic compounds Ti5Si3 and/or Ti5Si4 begins.

EVALUATION OF HYDROXYAPATITE-FORSTERITE-BIOACTIVE GLASS COMPOSITE NANOPOWDER PREPARED VIA SOL-GEL METHOD

2012 ◽  
Vol 05 ◽  
pp. 510-518
Author(s):  
MARYAM MAZROOEI SEBDANI ◽  
MOHAMMADHOSSEIN FATHI
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Bioactive Glass ◽  
Sintering Temperature ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Bioactive Ceramics ◽  
Transmission Electron ◽  
Alternative Approach ◽  
Sol Gel Process

In spite of attractive bioactivity of bioactive ceramics i.e. hydroxyapatite and bioactive glasses, their poor mechanical properties have restricted their clinical applications. To overcome these limitations, an alternative approach suggested is preparation a composite including these bioactive ceramics with others. It is expected that a ceramic reinforcement with reduced grain size below 100 nm promotes theirs. The aim of this work was fabrication and characterization of hydroxyapatite-forsterite-bioglass composite nanopowder. Novel hydroxyapatite-forsterite-bioglass composite nanopowder was synthesized by incorporation of the forsterite and bioactive glass in hydroxyapatite matrix via a sol-gel process. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and fourier transform infrared (FTIR) spectroscopy techniques were utilized in order to evaluate the phase composition, agglomerates size distribution, morphology and particle size and functional groups of synthesized. The effects of sintering temperature and time were also investigated. Results showed that the appropriate temperature for calcination was 600°C and the particle size of composite nanopowder was about 60-70nm. The decomposition of hydroxyapatite was increased with the increase of the sintering temperature and sintering time. Obtained results indicate that prepared composite nanopowder could be a good candidate for medical applications.

Sol-gel derived Nd1/3La1/3Ca1/3MnO3: Phase evolution and preparation of films and nanopowders

2007 ◽  
Vol 22 (6) ◽  
pp. 1737-1743 ◽  
Author(s):  
A. Pohl ◽  
G. Westin
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Single Phase ◽  
Sol Gel ◽  
Phase Evolution ◽  
Perovskite Oxide ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Cell Parameters ◽  
Transmission Electron

An all-alkoxide sol-gel route to the formation of Nd1/3La1/3Ca1/3MnO3thin films and powders has been developed. The microstructural evolution on heat treatment of the gel to yield the perovskite oxide was monitored by means of thermogravimetric analysis-differential scanning calorimetry, powder x-ray diffraction (XRD), Fourier transform infrared spectroscopy, and transmission electron microscopy (TEM)-energy dispersive spectroscopy (EDS). It was found that the amorphous gel consists of hydrated oxo-carbonate without organic residues, and on heating it decomposes in several steps, finally forming single-phase perovskite at 680 °C. Further heating results in only slight changes in the cell parameters and crystal growth. Films were prepared by spin coating, followed by heat treatment in air to a temperature of 800 °C, and studied by scanning electron microscopy, TEM-EDS, and XRD. Films on Al2O3were more porous, while films on Pt–TiO2–SiO2–Si were rather dense and consisted of areas with different crystal orientations.

Synthesis and characteristics of nanocrystalline materials in Ti, B, C and N containing system

Open Physics ◽  
2011 ◽  
Vol 9 (2) ◽  
Author(s):  
Anna Biedunkiewicz ◽  
Paweł Figiel ◽  
Urszula Gabriel ◽  
Marta Sabara ◽  
Stanisław Lenart
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Ceramic Materials ◽  
Nanocrystalline Powders ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
C And N ◽  
Two Stages

AbstractIn this work, the results of investigations of manufacturing ceramic materials on the basis of Ti, B, C and N containing systems are presented. The nanocrystalline ceramics were synthesized using a non-hydrolytic sol-gel method. The process was carried out in two stages. In the first low-temperature stage the precursor was obtained. The synthesis of ceramic phases, however, was conducted in the second high-temperature stage, in an argon atmosphere. Depending on the initial composition of the mixtures, the temperature and the time, the following products were obtained: TiCx, TiCxN1−x, TiB2 and B4C.The course of the process was investigated by thermogravimetric and differential scanning calorimetry methods (TG-DSC) coupled with mass spectrometry (MS). The solid state products were identified with use of X-ray diffraction (XRD). The size of the crystallites was estimated by the Scherrer method. The structure and morphology images of nanocrystalline powders were obtained using scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

Evaluation of Mechanochemical and Hydrothermal Transformations in a Wet-Milled Alumina by Transmission Electron Microscopy and Thermal Analysis

2016 ◽  
Vol 881 ◽  
pp. 46-51
Author(s):  
Humberto Naoyuki Yoshimura ◽  
Maurício Batista de Lima ◽  
Sydney Ferreira Santos ◽  
Fernando dos Santos Ortega
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Transmission Electron Microscopy ◽  
Hydrothermal Treatment ◽  
Basic Medium ◽  
Alumina Powder ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Aluminum Hydroxides ◽  
Transmission Electron

Milling and hydrothermal treatment of alumina powders in aqueous medium can result in surface transformations generating aluminum hydroxides. The aim of this work was to advance the understanding on these transformations. A α-alumina powder was ball milled in water at different pHs for 10 h, and then autoclaved (150 °C, 3 atm, 3 h). The powders were analyzed by transmission electron microscopy, differential scanning calorimetry simultaneously with thermogravimetry, X-ray diffraction, and infrared spectroscopy. It was observed that milling in basic medium caused the formation of doyleite [Al (OH3)] nanoparticles, which were fully converted to boehmite (AlOOH) by hydrothermal treatment. The boehmite fraction determined by thermal analysis was 1.7 wt%. The powder milled in acid medium had no mechanochemical and hydrothermal transformations.

Synthesis, Characterization, and Microwave Absorption Properties of SrFe12O19 Ferrites and FeNi3 Nanoplatelets Composites

2010 ◽  
Vol 148-149 ◽  
pp. 893-896 ◽  
Author(s):  
Ze Yang Zhang ◽  
Xiang Xuan Liu ◽  
You Peng Wu
Keyword(s):  
Electron Microscopy ◽  
Microwave Absorption ◽  
Composite Coatings ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Absorption Properties ◽  
Filling Fraction ◽  
Microwave Absorption Properties ◽  
Phase Reduction ◽  
Transmission Electron

M-typical SrFe12O19 ferrites and FeNi3 nanoplatelets were successfully prepared by the sol-gel method and solution phase reduction method, respectively. The crystalline and morphology of particles were studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The composite coatings with SrFe12O19 ferrites and FeNi3 nanoplatelets in polyvinylchloride matrix were prepared. The microwave absorption properties of these coatings were investigated in 2-18GHz frequency range. The results showed that the M-typical SrFe12O19 ferrites and FeNi3 nanoplatelets were obtained and they presented irregular sheet shapes. With the increase of the coating thickness, the absorbing peak value moves to the lower frequency. The absorbing peak values of the wave increase along with the increasing of the content of FeNi3 nanoplatelets filling fraction. When 40% SrFe12O19 ferrites is doped with 20% mass fraction FeNi3 nanoplatelets to prepare composite with 1.5mm thickness, the maximum reflection loss is -24.8 dB at 7.9GHz and the -10 dB bandwidth reaches 3.2GHz.

Effect of Synthesis Temperature on Particles Size and Morphology of Zirconium Oxide Nanoparticle

2017 ◽  
Vol 50 ◽  
pp. 18-31 ◽  
Author(s):  
Rudzani Sigwadi ◽  
Simon Dhlamini ◽  
Touhami Mokrani ◽  
Patrick Nonjola
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Zirconium Oxide ◽  
Thermo Gravimetric Analysis ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Crystallite Sizes ◽  
Ft Ir

The paper presents the synthesis and investigation of zirconium oxide (ZrO2) nanoparticles that were synthesised by precipitation method with the effects of the temperatures of reaction on the particles size, morphology, crystallite sizes and stability at high temperature. The reaction temperature effect on the particle size, morphology, crystallite sizes and stabilized a higher temperature (tetragonal and cubic) phases was studied. Thermal decomposition, band structure and functional groups were analyzed by Brunauer-Emmett-Teller (BET), Scanning Electron Microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), Thermo-gravimetric analysis (TGA) and Fourier transform infrared (FT-IR). The crystal structure was determined using X-ray diffraction. The morphology and the particle size were studied using (SEM) and (TEM). The shaped particles were confirmed through the SEM analysis. The transmission electron microscopic analysis confirmed the formation of the nanoparticles with the particle size. The FT-IR spectra showed the strong presence of ZrO2 nanoparticles.

scholarly journals Magnetic PbFe12O19-TiO2 nanocomposites and their photocatalytic performance in the removal of toxic pollutants

2018 ◽  
Vol 41 (3-4) ◽  
pp. 53-62 ◽  
Author(s):  
Behnaz Lahijani ◽  
Kambiz Hedayati ◽  
Mojtaba Goodarzi
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Performance ◽  
Sol Gel ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Gel Method ◽  
Sol Gel Method ◽  
Photocatalytic Effect ◽  
Transmission Electron ◽  
Ultraviolet Light Irradiation

Abstract In this work, the PbFe12O19 nanoparticles were prepared by the simple and optimized precipitation method with different organic surfactants and capping agents. In the next step, the TiO2 nanoparticles were synthesized using the sol-gel method. At the final step, the PbFe12O19-TiO2 nanocomposites were prepared via the sol-gel method. The effect of the precipitating agent on the morphology and particle size of the products was investigated. The prepared products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. The results obtained by the vibrating sample magnetometer show the magnetic properties of the ferrite nanostructures. The photocatalytic effect of the PbFe12O19-TiO2 nanocomposite on the elimination of the azo dyes (acid black, acid violet and acid blue) under ultraviolet light irradiation was evaluated. The results indicate that the prepared nanocomposites have acceptable magnetic and photocatalytic performance.

scholarly journals Biosynthesized gold nanoparticles-doped hydroxyapatite as antibacterial and antioxidant nanocomposite

2021 ◽  
Author(s):  
Is Fatimah ◽  
Putwi Widya Citradewi ◽  
Amri Yahya ◽  
Bambang Nugroho ◽  
Habibi Hidayat ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Antioxidant Activity ◽  
Particle Size ◽  
Gold Nanoparticles ◽  
Antibacterial Activity ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Dpph Scavenging Activity ◽  
Dpph Scavenging

Abstract The composite of green synthesized gold nanoparticles (Au NPs)-doped hydroxyapatite (HA) has been prepared. The gold nanoparticles were produced via bioreduction of HAuCl4 with Clitoria ternatea flower extract, and utilized in the synthesis of hydroxyapatite using Ca(OH)2 and ammonium diphosphate as precursor. The aim of this research is to study the structural analysis of the composite and antibacterial activity test toward Eschericia coli, Staphylococcus aureus, Klebsiela pneumoniae, and Streptococcus pyogenes. In addition, the antioxidant activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging method. The monitoring of gold nanoparticles formation was conducted by UV–vis spectroscopy and particle size analyses, meanwhile the synthesized composite was studied using X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results showed that homogeneously dispersed gold nanoparticles in HA structure was obtained with the particle size ranging at 5-80 nm. The nanocomposite demonstrated antibacterial activity against tested bacteria. The nanocomposite expressed an antioxidant activity as shown by the DPPH scavenging activity of 66 and 58% at the concentration of 100 μg/mL and 50 μg/mL, respectively.

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