Experimental Investigations of the Detonation Synthesis of Micron Al2O3 by the Precursor of Thermal Decomposition

2014 ◽  
Vol 609-610 ◽  
pp. 165-168
Author(s):  
R.Y. Li ◽  
H.L. Yang ◽  
H.H. Yan ◽  
X.H. Wang ◽  
X.J. Li
Keyword(s):  
Thermal Decomposition ◽  
Weight Loss ◽  
Aluminum Hydroxide ◽  
Crystal Size ◽  
Endothermic Peak ◽  
Experimental Investigations ◽  
Detonation Synthesis ◽  
Average Crystal Size ◽  
Scherrer Equation ◽  
Average Size

The Al2O3 is synthesized by detonation of mixed explosive, prepared by mixing RDX and aluminum hydroxide named as precursor of thermal decomposition. The production of detonation is analysed by XRD, TEM and DTA/TG. The curve of XRD indicates that the production are (α+γ)-Al2O3. The average crystal size of Al2O3 is 126nm calculated by the Scherrer equation. The photographs of TEM show that all granules of Al2O3 are spherical, and the average size of granule is 1000nm. The visible exothermic or endothermic peak does not appear on the curve of DTA from 50 to 1300 degree Centigrade. The curve of TG indicates that the production of detonation generates 12% weight loss from 50 to 1300 degree Centigrade.

scholarly journals Nanostructured titanium dioxide average size from alternative analysis of Scherrer's Equation

2018 ◽  
Vol 23 (1) ◽  
Author(s):  
Francisco Marcone Lima ◽  
Felipe Mota Martins ◽  
Paulo Herbert França Maia Júnior ◽  
Ana Fabíola Leite Almeida ◽  
Francisco Nivaldo Aguiar Freire
Keyword(s):  
Titanium Dioxide ◽  
Crystal Size ◽  
Statistical Treatment ◽  
Average Crystal Size ◽  
X Ray Diffraction ◽  
Alternative Analysis ◽  
Nanostructured Titanium ◽  
X Ray ◽  
Unheated Sample ◽  
Average Size

ABSTRACT The materials sizing in nano-scale is a challenge to be overcome, because the size determined by various methods differ. In order to shed light about the nanomaterials sizing, a modified Scherrer's equation was applied to estimate more accurately the nanostructured titanium dioxide crystal size. The manufactured titanium dioxide-nanostructured powder with nominal average size about 21nm was used as the reference standard to determine the accurate of modified equation. From X-ray diffraction data, an average crystal size about 20.63 nm was achieved for unheated sample. To establish a relation between the result obtained with modified Scherrer's equation and the nominal average crystal size, a statistical treatment and a comparative assessment were performed. The average absolute divergence does not exceed 0.70 nm. The value of crystal size determined from X-ray data was in good agreement with that informed by the supplier. Additionally, the behavior of sample was studied as a function of temperature.

A Convenient Method for Preparing Well-Dispersed Er2Zr2O7 Nanocrystals

2010 ◽  
Vol 123-125 ◽  
pp. 611-614 ◽  
Author(s):  
Yu Ping Tong ◽  
Rui Zhu Zhang ◽  
Shun Bo Zhao ◽  
Chang Yong Li
Keyword(s):  
Particle Size ◽  
Combustion Synthesis ◽  
Crystal Size ◽  
Lattice Distortion ◽  
Combustion Method ◽  
Treatment Temperature ◽  
Synthesis Process ◽  
Thermal Treatment Temperature ◽  
Average Size ◽  
Xrd And Tem

Well-dispersed fluorite Er2Zr2O7 nanocrystals have been successfully prepared by a convenient salt-assistant combustion method. The effects of calcinations temperature and salt category on the characteristics of the products were investigated by XRD and TEM. The thermal treatment temperature has an important effect on crystal size and lattice distortion of the nanocrystals. The experiment showed that the introduction of salt in the combustion synthesis process resulted in the formation of well-dispersed Er2Zr2O7 nanocrystals. The average size was 30 nm and was in agreement with the XRD result, which indicated that the nanocrystals were uniform in particle size distribution. Moreover, the possible formation process in the salt-assisted combustion synthesis was also analyzed.

scholarly journals Structural and Magnetic Properties of NiZn Ferrite Nanoparticles Synthesized by a Thermal Decomposition Method

2020 ◽  
Vol 10 (18) ◽  
pp. 6279
Author(s):  
JinAh Hwang ◽  
Moonhee Choi ◽  
Hyo-Soon Shin ◽  
Byeong-Kwon Ju ◽  
MyoungPyo Chun
Keyword(s):  
Thermal Decomposition ◽  
Magnetic Permeability ◽  
Decomposition Method ◽  
Spinel Ferrite ◽  
Cutoff Frequency ◽  
Zinc Content ◽  
Ferrite Nanoparticles ◽  
Maximum Point ◽  
Thermal Decomposition Method ◽  
Scherrer Equation

Ni1−xZnxFe2O4 (x = 0.5, 0.6, 0.7) nanoparticles were synthesized by a thermal decomposition method. The synthesized particles were identified as pure spinel ferrite structures by X-ray diffraction analysis, and they were calculated to be 46–51 nm in diameter by the Scherrer equation, depending on the composition. In the FE-SEM image, the ferrite nanoparticles have spherical shapes with slight agglomeration, and the particle size is about 50 nm, which was consistent with the value obtained by the Scherrer equation. The lattice parameter of the ferrite nanoparticles monotonically increased from 8.34 to 8.358 Å as the Zn concentration increased from 0.5 to 0.7. Initially, the saturation magnetization value slowly decreases from 81.44 to 83.97 emu/g, then quickly decreases to 71.84 emu/g as the zinc content increases from x = 0.5, through 0.6, to 0.7. Ni1−xZnxFe2O4 toroidal samples were prepared by sintering ferrite nanoparticles at 1250 °C and exhibited faceted grain morphologies in the FE-SEM images with their grain sizes being around 5 µm regardless of the Zinc content. The real magnetic permeability (μ′) of the toroidal samples measured at 5 MHz was monotonically increased from 106, through 150, to 217 with increasing the Zinc content from x = 0.5, through 0.6, to 0.7. The cutoff frequency of the ferrite toroidal samples was estimated to be about 20 MHz from the broad maximum point in the plot of imaginary magnetic permeability (μ″) vs. frequencies, which seemed to be associated with domain wall resonance.

scholarly journals Hydrothermal Synthesis of Hematite Nanoparticles Decorated on Carbon Mesospheres and Their Synergetic Action on the Thermal Decomposition of Nitrocellulose

Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 968 ◽  
Author(s):  
Abdenacer Benhammada ◽  
Djalal Trache ◽  
Mohamed Kesraoui ◽  
Salim Chelouche
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Analytical Techniques ◽  
Decomposition Reaction ◽  
Decomposition Temperature ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Nano Catalyst ◽  
Average Size ◽  
A Minor

In this study, carbon mesospheres (CMS) and iron oxide nanoparticles decorated on carbon mesospheres (Fe2O3-CMS) were effectively synthesized by a direct and simple hydrothermal approach. α-Fe2O3 nanoparticles have been successfully dispersed in situ on a CMS surface. The nanoparticles obtained have been characterized by employing different analytical techniques encompassing Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The produced carbon mesospheres, mostly spherical in shape, exhibited an average size of 334.5 nm, whereas that of Fe2O3 supported on CMS is at around 80 nm. The catalytic effect of the nanocatalyst on the thermal behavior of cellulose nitrate (NC) was investigated by utilizing differential scanning calorimetry (DSC). The determination of kinetic parameters has been carried out using four isoconversional kinetic methods based on DSC data obtained at various heating rates. It is demonstrated that Fe2O3-CMS have a minor influence on the decomposition temperature of NC, while a noticeable diminution of the activation energy is acquired. In contrast, pure CMS have a slight stabilizing effect with an increase of apparent activation energy. Furthermore, the decomposition reaction mechanism of NC is affected by the introduction of the nano-catalyst. Lastly, we can infer that Fe2O3-CMS may be securely employed as an effective catalyst for the thermal decomposition of NC.

Synthesis and thermal decomposition kinetics of poly(methyl methacrylate)-b-poly(styrene) block copolymers

2015 ◽  
Vol 30 (5) ◽  
pp. 691-706 ◽  
Author(s):  
Xinghua Guan ◽  
Xiaoyan Ma ◽  
Hualong Zhou ◽  
Fang Chen ◽  
Zhiguang Li
Keyword(s):  
Thermal Stability ◽  
Thermal Decomposition ◽  
Weight Loss ◽  
Block Copolymers ◽  
Methyl Methacrylate ◽  
Terminal Group ◽  
Loss Ratio ◽  
Poly Methyl Methacrylate ◽  
Second Stage ◽  
Weight Loss Ratio

Two diblock copolymers of poly(methyl methacrylate)- block-poly(styrene) with chlorine as terminal group (PMMA- b-PS-Cl) were synthesized via two-step atom transfer radical polymerization. The structures of the block copolymers were characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, and gel permeation chromatography. Thermal properties including glass transition temperature ( Tg) and thermal stability were studied by differential scanning calorimetry and thermogravimetric analysis (TGA), respectively. The block copolymers of PMMA- b-PS-Cl exhibited two glass transitions, which were attributed to the Tgs of PMMA and PS segments, respectively. According to TGA, thermal decompositions of PMMA macro-initiator and PMMA- b-PS-Cl block copolymers had two stages. The weight loss ratio in the second stage was more significant than that in the first stage, which may be attributed to the separation of the halogen atom from the terminal group and the formation of a double bond. The breaking down of the backbone dominates in the second stage in which the weight loss ratio was more than 70%, represented the main stage of pyrolysis. It was found that the introduction of the PS chain remarkably enhanced the thermal stability of the copolymer, thus endowing the block copolymers high activation energy for thermal decomposition. On the other hand, the remaining two pyrolysis procedures further indicated that thermodynamic mechanism didn’t change due to the introduction of PS segments.

scholarly journals Composite Coatings of Chromium and Nanodiamond Particles on Steel

2017 ◽  
Vol 62 (4) ◽  
pp. 2421-2424 ◽  
Author(s):  
N. Gidikova ◽  
M. Sulowski ◽  
V. Petkov ◽  
R. Valov ◽  
G. Cempura
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Composite Coating ◽  
Composite Coatings ◽  
Machine Building ◽  
Chromium Coating ◽  
Detonation Synthesis ◽  
Micro Structure ◽  
X Ray ◽  
Average Size

AbstractChrome plating is used to improve the properties of metal surfaces like hardness, corrosion resistance and wear resistance in machine building. To further improve these properties, an electrodeposited chromium coating on steel, modified with nanodiamond particles is proposed. The nanodiamond particles (average size 4 nm measured by TEM) are produced by detonation synthesis (NDDS). The composite coating (Cr+NDDS) has an increased thickness, about two times greater microhardness and finer micro-structure compared to that of unmodified chromium coating obtained under the same galvanization conditions. In the microstructure of specimen obtained from chrome electrolyte with concentration of NDDS 25 g/l or more, “minisections” with chromium shell were found. They were identified by metallographic microscope and X-ray analyser on etched section of chromium plated sample. The object of further research is the dependence of the presence of NDDS in the composite coating from the nanodiamond particles concentration in the chroming electrolyte.

scholarly journals Microbial-Physical Synthesis of Fe and Fe3O4 Magnetic Nanoparticles Using Aspergillus niger YESM1 and Supercritical Condition of Ethanol

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Mai Abdeen ◽  
Soraya Sabry ◽  
Hanan Ghozlan ◽  
Ahmed A. El-Gendy ◽  
Everett E. Carpenter
Keyword(s):  
Magnetic Nanoparticles ◽  
Aspergillus Niger ◽  
Biomedical Applications ◽  
Large Scale ◽  
Crystal Size ◽  
Supercritical Condition ◽  
Scale Production ◽  
Large Scale Production ◽  
Average Size ◽  
Biophysical Method

Magnetic Fe and Fe3O4 (magnetite) nanoparticles are successfully synthesized using Aspergillus niger YESM 1 and supercritical condition of liquids. Aspergillus niger is used for decomposition of FeSO4 and FeCl3 to FeS and Fe2O3, respectively. The produced particles are exposed to supercritical condition of ethanol for 1 hour at 300°C and pressure of 850 psi. The phase structure and the morphology measurements yield pure iron and major Fe3O4 spherical nanoparticles with average size of 18 and 50 nm, respectively. The crystal size amounts to 9 nm for Fe and 8 nm for Fe3O4. The magnetic properties are measured to exhibit superparamagnetic- and ferromagnetic-like behaviors for Fe and Fe3O4 nanoparticles, respectively. The saturation magnetization amounts to 112 and 68 emu/g for Fe and Fe3O4, respectively. The obtained results open new route for using the biophysical method for large-scale production of highly magnetic nanoparticles to be used for biomedical applications.

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