Micropyretic synthesis of MoSi2 powders through an aluminothermic reaction

1999 ◽  
Vol 14 (5) ◽  
pp. 2023-2028 ◽  
Author(s):  
Ming Fu ◽  
S. Penumella ◽  
J. A. Sekhar
Keyword(s):  
Average Particle Size ◽  
Molybdenum Disilicide ◽  
Xrd Analysis ◽  
Phosphoric Acid Solution ◽  
Synthesis Process ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Powder Mixtures ◽  
X Ray ◽  
Aluminothermic Reaction

An aluminothermic reaction starting with inexpensive MoO3, SiO2, and Al powders was utilized to prepare molybdenum disilicide (MoSi2) powders by the micropyretic/combustion synthesis process and leaching. The combustion-synthesized product was porous and could readily be crushed into powders. X-ray diffraction (XRD) analysis revealed that the product of such a reaction consisted of α–Al2O3, MoSi2, and a small amount of Mo(Si,Al)2 and Mo5Si3. The reason for the formation of Mo(Si, Al)2 phase is discussed. MoSi2 powders were obtained by leaching out the Al2O3 from the synthesized powder mixtures in boiling phosphoric acid solution. The synthesized MoSi2 powders, including a small amount of Mo(Si, Al)2 and Mo5Si3, were very fine with an average particle size of about 1 μm.

Preparation and Magnetic Properties of Carbon Encapsulated Fe-Cu Alloy Nanoparticles

2010 ◽  
Vol 177 ◽  
pp. 673-676 ◽  
Author(s):  
Jun Xue ◽  
Hou Kui Xiang ◽  
Hong Qiao Ding ◽  
Shu Li Pang ◽  
Xue Hua Wang ◽  
...  
Keyword(s):  
Magnetic Measurement ◽  
Average Particle Size ◽  
Soft Magnetic Property ◽  
Copper Nitrate ◽  
Synthesis Process ◽  
Ferric Nitrate ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cu Alloy

Carbon encapsulated Fe-Cu alloys nanoparticles were synthesized by using ferric nitrate, copper nitrate as metal sources and using sucrose as carbon source. The synthesis process involved a step of hydrazine hydrate reduction in alcohol solution and a step of annealing carbonization. The as-prepared samples were characterized by X-ray diffraction technique, X-ray energy dispersion spectrograph, trans- mission electron microscopy and Raman spectroscopy. The results showed the sample was core / shell structure, the metalic core was crystalline FeCu4 alloy, the shell was amorphous carbon, and the average particle size was about 51nm. The magnetic measurement by using a vibrating sample magnetometer revealed that the sample has ultra-soft magnetic property with the saturation magnetization Ms of 13.01 emu/g, residual magnetization Mr of 0.37 emu/g and coercive forces Hc of 54.43 Oe at room temperature.

scholarly journals Thermal, Structural, and Physical Properties of Freeze Dried Tropical Fruit Powder

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
K. A. Athmaselvi ◽  
C. Kumar ◽  
M. Balasubramanian ◽  
Ishita Roy
Keyword(s):  
Particle Size ◽  
Physical Properties ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Tropical Fruit ◽  
X Ray ◽  
Freeze Dried ◽  
Fruit Powder ◽  
Lcr Meter

This study evaluates the physical properties of freeze dried tropical (guava, sapota, and papaya) fruit powders. Thermal stability and weight loss were evaluated using TGA-DSC and IR, which showed pectin as the main solid constituent. LCR meter measured electrical conductivity, dielectric constant, and dielectric loss factor. Functional groups assessed by FTIR showed presence of chlorides, and O–H and N–H bonds in guava, chloride and C–H bond in papaya, and chlorides, and C=O and C–H bonds in sapota. Particle size and type of starch were evaluated by X-ray diffraction and microstructure through scanning electronic microscopy. A semicrystalline profile and average particle size of the fruit powders were evidenced by X-ray diffraction and lamellar/spherical morphologies by SEM. Presence of A-type starch was observed in all three fruits. Dependence of electric and dielectric properties on frequency and temperature was observed.

scholarly journals A Comparative Study of Nanostructures of CuO/Cu2O Fabricated via Potentiostatic and Galvanostatic Anodization

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
S. Mary Margaret ◽  
Albin John P. Paul Winston ◽  
S. Muthupandi ◽  
P. Shobha ◽  
P. Sagayaraj
Keyword(s):  
Thermal Stability ◽  
Comparative Study ◽  
Aqueous Electrolyte ◽  
Average Particle Size ◽  
Xrd Analysis ◽  
Molecular Vibration ◽  
Synthesis Process ◽  
Average Particle ◽  
Good Crystallinity ◽  
Cu Foil

A detailed comparative study on the synthesis process of coral-like CuO/Cu2O nanorods (NRs) and nanopolycrystals (NPCs) fabricated on Cu foil employing aqueous electrolyte via potentiostatic (POT) and galvanostatic (GAL) modes is discussed. The structural, morphological, thermal, compositional, and molecular vibration of the prepared CuO/Cu2O nanostructures was characterized by XRD, HRSEM, TG/DTA, FTIR, and EDX techniques. XRD analysis confirmed the crystalline phase of the formation of monoclinic CuO and cubic Cu2O nanostructures with well-defined morphology. The average particle size was found to be 21.52 nm and 26.59 nm for NRs (POT) and NPCs (GAL), respectively, and this result is corroborated from the HRSEM analysis. POT synthesized nanoparticle depicted a higher thermal stability up to 600°C implying that the potentiostatically grown coral-like NRs exhibit a good crystallinity and well-ordered morphology.

Preparation and Luminescence Properties of Sr2CeO4 Doped with Ho3+

2013 ◽  
Vol 591 ◽  
pp. 272-276
Author(s):  
Fang Zhang ◽  
Chao Song ◽  
Ling Li Ma ◽  
Xiao Li Xu ◽  
Zi Fei Peng
Keyword(s):  
Sintering Temperature ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Solid State Method ◽  
X Ray ◽  
Ultraviolet Excitation ◽  
Near Ultraviolet ◽  
State Method ◽  
Photo Luminescent

Sr2CeO4: Ho3+ was prepared by high-temperature solid-state method. The products were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and photo luminescent (PL). The Sr2CeO4:Ho3+ phosphors showed a red emission under the near-ultraviolet excitation (280 nm) and the main emission centered at 475 nm. It has been found that A+ (A+ = Li+, Na+ or K+) codoped Sr2CeO4: Ho3+ phosphors could lead to a remarkable increase of photoluminescence. Luminous intensity was the highest when doping Li+ ions. Investigation indicated that Sr2Ce0.989O4: 0.001Ho3+, 0.01Li+ exhibited the strongest emission. The average particle size was about 6 um. The optimum sintering temperature was 1200 °C and the possible mechanism was also discussed.

scholarly journals Facile Microemulsion Synthesis of Vanadium-Doped ZnO Nanoparticles to Analyze the Compositional, Optical, and Electronic Properties

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 821 ◽  
Author(s):  
H.S. Ali ◽  
Ali Alghamdi ◽  
G. Murtaza ◽  
H.S. Arif ◽  
Wasim Naeem ◽  
...  
Keyword(s):  
Zno Nanoparticles ◽  
Average Particle Size ◽  
Xrd Analysis ◽  
Attenuated Total Reflection ◽  
Lattice Parameters ◽  
Average Particle ◽  
Structural Morphology ◽  
Wurtzite Phase ◽  
X Ray ◽  
Doped Zno

In this work, microemulsion method has been followed to synthesize vanadium-doped Zn1−xVxO (with x = 0.0, 0.02, 0.04, 0.06, 0.08, and 0.10) nanoparticles. The prepared samples are characterized by several techniques to investigate the structural, morphology, electronic, functional bonding, and optical properties. X-ray diffractometer (XRD) analysis confirms the wurtzite phase of the undoped and V-doped ZnO nanoparticles. Variation in the lattice parameters ensures the incorporation of vanadium in the lattice of ZnO. Scanning electron microscopy (SEM) shows that by increasing contents of V ions, the average particle size increases gradually. X-ray Absorption Near Edge Spectroscopy (XANES) at the V L3,2 edge, oxygen K-edge, and Zn L3,2 edge reveals the presence and effect of vanadium contents in the Zn host lattice. Furthermore, the existence of chemical bonding and functional groups are also asserted by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). UV–Visible analysis shows that by increasing V+ contents, a reduction up to 2.92 eV in the energy band gap is observed, which is probably due to an increase in the free electron concentration and change in the lattice parameters.

scholarly journals Structural Analysis of Platinum Nanoparticles on Carbon Nanotube Surface as Electrocatalyst System

2017 ◽  
Vol 9 (2) ◽  
pp. 60 ◽  
Author(s):  
Sudirman Sudirman ◽  
Indriyati Indriyati ◽  
Wisnu Ari Adi ◽  
Rike Yudianti ◽  
Emil Budianto
Keyword(s):  
Cell Volume ◽  
Unit Cell Volume ◽  
Average Particle Size ◽  
Unit Cell ◽  
Lattice Parameters ◽  
Atomic Density ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Great Opportunity ◽  
X Ray

Synthesis of Pt/CNT composite by using sol gel method has been performed which the composition of CNT on the composite are vary, (x = 20, 40, 60 and 80 wt%). Performance of composite was characterized by Transmission Electron Microscope (TEM) and X-Ray Diffraction (XRD), respectively. In the refinement results of X-ray diffraction pattern, the composite consists of two phases, namely, carbon and platinum phases. Carbon phase has a structure hexagonal (P 63 m c) with lattice parameters a = b = 2.451(2) Å and c = 6.89(1) Å, α = β = 90° and γ = 120°, the unit cell volume of V = 35.8(1) A3, and the atomic density of ρ = 2.224 g.cm-3. While platinum phase has the structure of cubic (F m -3 m) with lattice parameters a = b = c = 3.921(2) Å, α = β = γ = 90°, the unit cell volume of V = 60.3(1) A3, and the atomic density of ρ = 21.487 g.cm-3.According to the image of TEM, the average particle size for Pt nano particle is estimated to range from 4.1-4.3 nm. While the cavity diameter average of CNT is estimated to range from 5.9-7.5 nm. Based on the calculation, the crystallite size of the Pt particle was around 4.31 nm. The optimum value of dispersed Pt into CNT occurred at 60 wt% CNT with the best composition of Pt in the unit cell of cystal structure. We concluded that this study successfully dispersed Pt nanoparticles onto CNT formed Pt/CNT composite. This was a great opportunity that the composite can be applied as electrocatalyst system on fuel cell application.

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.

Effect of Concentration of Iron Oxide on Crystallization Behavior in Leadless Iron Oxide Crystalline Glaze

2012 ◽  
Vol 554-556 ◽  
pp. 18-22
Author(s):  
Supakorn Silakate ◽  
Anucha Wannagon ◽  
Apinon Nuntiya
Keyword(s):  
Iron Oxide ◽  
Nepheline Syenite ◽  
Crystallization Behavior ◽  
Raw Materials ◽  
Average Particle Size ◽  
Average Particle ◽  
Oxide Content ◽  
Iron Oxide Content ◽  
X Ray Diffraction ◽  
X Ray

The objectives of this study were to prepare leadless crystalline glazes from iron oxide by using low temperature firing (1,100°C) and to study the effect of concentration of iron oxide on the phase composition of the glaze raw materials on phase transformation in leadless iron oxide crystalline glaze. The crystalline phases were investigated by using the DTA, X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The composition of the glaze raw materials compose of nepheline syenite, colemanite, pottery stone, bentonite, ZnO, Li2CO3, SiOSubscript text2 and 10, 15 and 20%(w/w) iron oxide (Fe2O3). The glaze raw materials were ground for homogeneous mixtures by ball milling for 24h. The average particle size of the mixture was 3.86 µm. The glaze bodies were carried to firing at 1,100°C at the heating rate of 2°C/min and soaking for 0.5h. Then, the glaze bodies were cooled at the cooling rate of 1°C/min and maintained at 1,080°C for 3h and then maintained at 980°C for 1h, respectively. From the experiment results, it was found that the crystallization temperatures (Tc) of franklinite (ZnFe2O4) and anorthite (CaAl2Si2O8) depend on the concentration of iron oxide content.

The Fabrication of Refractory Cordierite from Aluminium Buff Mixture

2016 ◽  
Vol 690 ◽  
pp. 97-102
Author(s):  
Nuntaporn Kongkajun ◽  
Parinya Chakartnarodom ◽  
Warunee Borwornkiatkaew
Keyword(s):  
Microstructural Analysis ◽  
Secondary Phase ◽  
Xrd Analysis ◽  
Batch Composition ◽  
Brazilian Test ◽  
Raw Material ◽  
X Ray Diffraction ◽  
Powder Mixtures ◽  
X Ray ◽  
Properties Of Materials

The aim of this work is to propose the utilization of aluminium buff from aluminium part manufacturer as a raw material for cordierite batch composition. The powder mixtures were compacted by uniaxial pressing. The green compacts were sintered at temperature in the range 1300-1400°C for 2 hours in air. The physical properties were characterized by Archimedes method, Brazilian test and dilatometry. Phase and microstructural analysis were done by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD analysis showed the major phase was cordierite along with sapphirine as a secondary phase. The fired properties of materials were demonstrated that the optimal properties was achieved from the specimen sintered at 1375 °C.

scholarly journals Chemical, morphological characterizations of Ririwai biotite and determination of yield point of its weighting agent application in drilling mud

2021 ◽  
Vol 40 (2) ◽  
pp. 269-274
Author(s):  
N. Salahudeen ◽  
U. Mohammed ◽  
M.N. Yahya
Keyword(s):  
Yield Point ◽  
Xrd Analysis ◽  
Average Particle ◽  
Drilling Mud ◽  
X Ray Diffraction ◽  
X Ray ◽  
Edx Analysis ◽  
Silica Alumina ◽  
Electron Dispersion

Chemical, morphological characterizations and drilling mud yield point impact of Ririwai biotite have been investigated and reported in this work. Local Ririwai biotite mined in Doguwa Local Government Area of Kano State was used as a weighting agent in drilling mud formulation. Scanning Electron Microscopy (SEM) characterization, X-ray Diffraction (XRD) and Electron Dispersion X-ray (EDX) analysis of the Ririwai biotite were carried out. Water-based drilling mud was prepared using commercial bentonite according to the API 13A Standard. Effect of gradual addition of Ririwai weighting agent; 0 – 100 wt%, on the yield point of the formulated drilling mud was studied. XRD analysis showed that the dominant mineral phase in the material was biotite. Morphological analysis carried out showed that the Ririwai biotite had a sheet-like morphology while the commercial bentonite had clumpy morphology. The estimated average particle sizes were 60 and 25 μm for the Ririwai biotite and commercial bentonite, respectively. EDX analysis showed that silica-alumina ratio of the Ririwai biotite was 9.3 while that of the commercial bentonite was 1.58. The optimum yield point of the formulated drilling mud was 2.0 lb/100 ft2 corresponding to formulation having 0 – 30 wt% weighting agent composition. The specific gravity of Ririwai biotite was determined as 2.4.

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