scholarly journals Microwave-Assisted Combustion Synthesis of Nanocrystalline ZnO Powders Using Zinc Nitrate and Various Amount of Organic Fuels as Reactants: Influence of Reactant Parameters - A Status Review

Nano Hybrids ◽  
2014 ◽  
Vol 6 ◽  
pp. 75-110
Author(s):  
L.C. Nehru ◽  
C. Sanjeeviraja
Keyword(s):  
Combustion Synthesis ◽  
Flame Temperature ◽  
Synthesis Method ◽  
Zinc Nitrate ◽  
Adiabatic Flame Temperature ◽  
Molar Ratios ◽  
Microwave Assisted ◽  
Organic Fuels ◽  
Zno Powders ◽  
Xrd Techniques

Nanocrystalline ZnO powders have been synthesized by a novel and simple microwave-assisted combustion synthesis method using urea, glycine, carbohydrazine and citric acid as fuels and zinc nitrate as oxidant. The starting materials were directly mixed and a slurry precursor with high homogeneity was formed due to the hygroscopicity of the reactants. The precursor could be ignited at room temperature, resulting in dry, loose and voluminous ZnO powders. An interpretation based on an adiabatic flame temperature, amount of gases produced during reaction for various fuel-to-oxidizer molar ratios (ψ), has been proposed for the nature of combustion and its correlation with the characteristics of as-synthesized product. The variation of adiabatic flame temperature (Tad) with the ψ value was calculated theoretically according to the thermodynamic concept. The reaction process of the precursor was investigated by XRD techniques.

scholarly journals Nb2O5 nanoparticles obtained by microwave assisted combustion synthesis under different conditions

2021 ◽  
Vol 15 (2) ◽  
pp. 128-135
Author(s):  
Thaís Luiz ◽  
Fabio Nakagomi ◽  
Reny Renzetti ◽  
Guilherme Siqueira
Keyword(s):  
Combustion Synthesis ◽  
Diffuse Reflectance Spectroscopy ◽  
Low Cost ◽  
Synthesis Method ◽  
Particle Growth ◽  
Synthesis Temperature ◽  
Band Gap Energy ◽  
Stoichiometric Ratio ◽  
Synthesis Of Nanoparticles ◽  
Microwave Assisted

The microwave assisted combustion synthesis (MACS) as a new, quick and low cost synthesis method was used for preparation of niobium pentoxide (Nb2O5) powders. The present paper investigated the effect of reactant concentrations (ammonium niobium oxalate, urea and ammonium nitrate) on the characteristics of Nb2O5 nanoparticles. Three samples were synthesized with stoichiometric ratio between the fuel and oxidant (C1), excess of oxidant (C2) and excess of fuel (C3). In all samples, Nb2O5 crystalline nanoparticles with irregular morphology were detected. The synthesis of nanoparticles with smaller diameter in the C2 and C3 samples was confirmed by greater values of band gap energy measured through UV-Visible diffuse reflectance spectroscopy (indicating quantum confinement) and by the Rietveld refinement of X-ray diffraction patterns. The results showed that the amounts of oxidant and fuel can change synthesis temperature, influencing the final characteristics of the particles, such as size and existent phases. In these cases the excess of oxidant and fuel in the C2 and C3 samples, respectively, decreases the average synthesis temperature and decelerates the particle growth and the formation of the monoclinic phase.

Synthesis and Characterization of Nanocrystalline ZnO Powders by a Novel Combustion Synthesis Method

2010 ◽  
Vol 152-153 ◽  
pp. 674-678 ◽  
Author(s):  
Bing Wang ◽  
Li Dan Tang ◽  
Jian Zhong Wang
Keyword(s):  
Crystal Structure ◽  
Combustion Synthesis ◽  
Synthesis Method ◽  
Synthesis And Characterization ◽  
Particle Sizes ◽  
Hexagonal Crystal Structure ◽  
Hexagonal Crystal ◽  
Zno Powders ◽  
Scherrer Formula

Nanocrystalline ZnO powders have been synthesized by a novel combustion synthesis method using glycine and urea as mixed fuels and zinc nitrates as oxidant. The as-synthesized ZnO powders are characterized by DSC, XRD and SEM. Results show that the as-synthesized ZnO powders show well crystalline with hexagonal crystal structure and purity without any other impurities and the particle sizes are about 50~70nm calculated by the Scherrer formula.

Preparation of zinc oxide (ZnO) powders with different types of morphology by a combustion synthesis method

2007 ◽  
Vol 140 (1-2) ◽  
pp. 31-37 ◽  
Author(s):  
Cheng-Shiung Lin ◽  
Chyi-Ching Hwang ◽  
Wei-Hua Lee ◽  
Wei-Yin Tong
Keyword(s):  
Zinc Oxide ◽  
Combustion Synthesis ◽  
Synthesis Method ◽  
Different Types ◽  
Zno Powders

Preparation of Mo (Si, Al) 2 by Microwave Assisted Combustion Synthesis

2011 ◽  
Vol 103 ◽  
pp. 509-512 ◽  
Author(s):  
Si Wen Tang ◽  
Jian Hui Yan ◽  
Cheng Zhang Peng
Keyword(s):  
Phase Composition ◽  
Combustion Synthesis ◽  
Phase Structure ◽  
Heating Temperature ◽  
Synthesis Method ◽  
Sem Analysis ◽  
Microwave Energy ◽  
Microwave Assisted Synthesis ◽  
Microwave Assisted ◽  
Al Substitution

Al substituted MoSi2composites were prepared by using microwave assisted synthesis method, which is a self-propagation synthesis ignited by microwave energy. The composition and microstructure of as combusted powder had been detected by XRD and SEM analysis. Result shows that the pre-heating temperature and phase composition of microwave assisted combustion synthesis is largely influenced by the content of aluminum. The phase structure of Mo(Si, Al)2alter from a mixture of MoSi2and Mo5Si3to nearly pure Mo (Si, Al)2with the increasing of Al substitution. The main mechanism is dissolution separation..

scholarly journals Combustion Synthesis Ironmaking: Investigation on Required Carbon Amount in Raw Material from the Viewpoint of Adiabatic Flame Temperature Calculation

2019 ◽  
Vol 19 (3) ◽  
pp. 696 ◽  
Author(s):  
Keisuke Abe ◽  
Ade Kurniawan ◽  
Masafumi Sanada ◽  
Takahiro Nomura ◽  
Tomohiro Akiyama
Keyword(s):  
Combustion Synthesis ◽  
Iron Ore ◽  
Flame Temperature ◽  
Target Material ◽  
Molten Iron ◽  
Raw Material ◽  
Sample Temperature ◽  
Fast Method ◽  
Adiabatic Flame Temperature ◽  
Temperature Calculation

Combustion synthesis (CS) is a simple and very fast method to synthesize a target material. New ironmaking method via the CS using carbon-infiltrated iron ore was proposed, and the possible conditions for the method were investigated. Adiabatic flame temperatures (Tad) of the CS reaction, maximum reachable temperatures in an adiabatic system, were calculated to estimate the sample temperature during the CS. To reach the adiabatic temperature of 1811 K, 23.9, 27.9, and 29.3 wt.%-C were required for Fe2O3, Fe3O4, and FeO, respectively. When the carbon amount is higher than the calculated one, molten iron which is separated from slag components should be obtained via the CS.

Morphological and Luminescent Characteristics of ZnO Nanopowders Doped with Europium

2008 ◽  
Vol 591-593 ◽  
pp. 745-749 ◽  
Author(s):  
T.S. Barros ◽  
Bráulio Silva Barros ◽  
S. Alves ◽  
Ruth Herta Goldsmith Aliaga Kiminami ◽  
Hélio Lucena Lira ◽  
...  
Keyword(s):  
Fine Particles ◽  
Synthesis Method ◽  
Secondary Phase ◽  
Vitreous Silica ◽  
Zinc Nitrate ◽  
Luminescence Characteristic ◽  
Structure Morphology ◽  
Zno Powders ◽  
Red Luminescence ◽  
Luminescence Characteristics

Zinc oxide was obtained by combustion reaction synthesis method using microwaves energy to provide ignition to the mixture of zinc nitrate, europium and urea. The influence of the europium concentration on the structure, morphology and luminescence characteristics of the ZnO powders was investigated. The proportion of each reagent and fuel was calculated based on the propellants chemistry concepts. The solutions were mixed in a vitreous silica basin and submitted of external heating in a microwaves oven until self-ignition occurred. The resulting powders were characterized by X-ray diffractometer (XRD), granulometric distribution, scanning electronic microscopy (SEM) and emission spectroscopy. The XRD results showed the formation of ZnO:Eu3+ as main phase and Eu2O3 as secondary phase. The powder presented morphology constituted of fine particles agglomerates (<100nm) and red luminescence characteristic from Eu3+ ion.

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