scholarly journals Slip-Jump Model for Carbon Combustion Synthesis of Complex Oxide Nanoparticles

2016 ◽  
Vol 18 (3) ◽  
pp. 223 ◽  
Author(s):  
A.A. Markov ◽  
M.A. Hobosyan ◽  
K.S. Martirosyan
Keyword(s):  
Combustion Synthesis ◽  
Ignition Temperature ◽  
Complex Oxides ◽  
Complex Oxide ◽  
Cylindrical Sample ◽  
Combustion Model ◽  
Combustion Heat ◽  
Theoretical Predictions ◽  
Lower Porosity ◽  
Carbon Combustion

Carbon Combustion Synthesis of Oxides (CCSO) is a promising method to produce submicron- and nano- sized complex oxides. The CCSO was successfully utilized for producing several complex oxides, a complete theoretical model including the sample porosity, flow parameters and reaction energetics is needed to predict the combustion parameters for CCSO. In this work, we studied the ignition temperature and combustion wave axial temperature distribution, activation energy, combustion heat and thermal losses for a typical CCSO synthesis for cylindrical samples of Ni-Zn ferrites with high (>85%) porosity. We developed a two level combustion model of chemically active nano-dispersed mixture, using the experimentally measured ignition temperature and combustion parameter values utilizing the slipjump method for high Knudsen numbers. The theoretical predictions of highly porous samples when the fl ow resistivity is small and the gas can easily fl ow through the cylindrical sample are in good agreement with the experimental data. The calculation of combustion characteristics for the lower porosity values demonstrated that the surface combustion was dominated due to high gas fl ow resistivity of the sample. Finger combustion features were observed at this combustion mode.

Carbon Combustion Synthesis of Ceramic Oxide Nanopowders

2010 ◽  
Vol 63 ◽  
pp. 236-245 ◽  
Author(s):  
Karen S. Martirosyan
Keyword(s):  
Combustion Synthesis ◽  
Large Scale ◽  
Combustion Process ◽  
Complex Oxides ◽  
Cost Effective ◽  
Complex Oxide ◽  
Thermal Reaction ◽  
Scale Production ◽  
Market Demand ◽  
Carbon Combustion

The rapidly growing market demand for nanoparticles calls for cost-effective and environmentally friendly technologies for their large-scale production. We developed a new, simple, economical and energy efficient synthesis of nanostructured complex oxides from inexpensive reactant mixtures, referred to as Carbon Combustion Synthesis of Oxides (CCSO). In CCSO the exothermic oxidation of carbon nanoparticles generates a steep thermal reaction wave that propagates through the solid reactant mixture converting it to the desired complex oxide product. CCSO is a modified form of SHS that maintains the advantages of SHS and circumvents some of its disadvantages. Specifically, it enables a more economical synthesis of complex oxides. The carbon used in CCSO is not incorporated in the product and is emitted from the sample as a CO2. A large gas emission provides a convective cooling mechanism trough the sample that significant reduces local temperature and prevents product partial melting and particles growth. CCSO does not require use of expensive fuel reactants and complex equipment and can be scaled up for continuous mass production. This paper reviewed the recent progress in the synthesis of advanced complex oxides nanoparticles by using carbon combustion process.

Carbon combustion synthesis of complex oxides: Process demonstration and features

AIChE Journal ◽  
2005 ◽  
Vol 51 (10) ◽  
pp. 2801-2810 ◽  
Author(s):  
K. S. Martirosyan ◽  
D. Luss
Keyword(s):  
Combustion Synthesis ◽  
Complex Oxides ◽  
Carbon Combustion

scholarly journals Screen-printing of ferrite magnetic nanoparticles produced by carbon combustion synthesis of oxides

2012 ◽  
Vol 111 (9) ◽  
pp. 094311 ◽  
Author(s):  
Karen S. Martirosyan ◽  
Chamath Dannangoda ◽  
Eduard Galstyan ◽  
Dmitri Litvinov
Keyword(s):  
Magnetic Nanoparticles ◽  
Combustion Synthesis ◽  
Screen Printing ◽  
Carbon Combustion

Optimized Preparation of Fe2O3/Al2O3 Composite with Sol-Gel Combustion Synthesis Method Based on Orthogonal Experimental Design

2011 ◽  
Vol 341-342 ◽  
pp. 215-220
Author(s):  
Bao Wen Wang ◽  
Chuan Chang Gao ◽  
Hai Bo Zhao ◽  
Chu Guang Zheng
Keyword(s):  
Experimental Design ◽  
Combustion Synthesis ◽  
Ignition Temperature ◽  
Sintering Temperature ◽  
Sol Gel ◽  
Synthesis Method ◽  
Influential Factor ◽  
Molar Ratio ◽  
Orthogonal Experimental Design ◽  
Gel Combustion

Fe2O3/Al2O3 composite at the mass ratio of 3:2 was prepared by sol-gel combustion synthesis using urea as fuel. The optimized preparation parameters were determined by the robust orthogonal experimental design (OED) method. Standard L9(34) orthogonal array was adopted, and the four factors were determined as the molar ratio of oxidizer nitrates to fuel urea Ф, relative amount of the deionized water added Rw, ignition temperature and sintering temperature. Range analysis of the relative importance of those four factors on the mean weight loss rate for the reduction of synthesized Fe2O3/Al2O3 with 50 vol% H2 indicated that the most influential factor was Ф, sintering temperature, Rw and ignition temperature in the descending order. And the optimized preparation parameters for Fe2O3/Al2O3 composite were Ф=1, Rw=7.5, ignition and sintering temperatures stabilized as 600°C and 950°C,respectively. Finally, the reaction characteristics of Fe2O3/Al2O3 prepared by SGCS and the other two reference methods (including sol-gel method and mechanical mixing method) were compared and the results verified that the optimized SGCS was the best option to synthesize Fe2O3/Al2O3 composite with good reaction performance.

Analyses of Coal and Sewage Sludge Co-Combustion Using Coats-Redfern Model

2012 ◽  
Vol 518-523 ◽  
pp. 3271-3274
Author(s):  
Huan Li ◽  
Yang Yang Li ◽  
Yi Ying Jin
Keyword(s):  
Activation Energy ◽  
Ignition Temperature ◽  
Burning Velocity ◽  
Fire Behavior ◽  
Volatile Matter ◽  
Water Evaporation ◽  
Fixed Carbon ◽  
Carbon Combustion ◽  
Blend Fuel ◽  
Dried Sludge

The co-combustibility of coal and sludge was investigated with thermogravimetric analysis. The results show that the burning process of sludge can be divided into three phases: water evaporation, volatile matter volatilization and combustion, fixed carbon combustion and burning out. The ignition temperature of sludge is only 260 degree centigrade at the beginning of volatile matter combustion. The addition of wet sludge or dried sludge will reduce the burning velocity of coal, and also decrease the ignition temperature. However the blend of coal and sludge has not an obvious stage of the volatile matter volatilization and combustion. The activation energy of the sludge is lower than that of the coal. The addition of wet sludge or dried sludge will decrease the activation energy of the blend fuel, and improve the fire behavior. On the whole, the sludge addition has little influence on the combustion of the coal when the addition ratio is lower than 10%.

Synthesis of Complex-oxide Nanorods via Pulsed-laser Deposition

2010 ◽  
Vol 1256 ◽  
Author(s):  
John E Mathis ◽  
Gyula Eres ◽  
Claudia Cantoni ◽  
Kyunghoon Kim ◽  
Hans Christen
Keyword(s):  
Pulsed Laser Deposition ◽  
Sol Gel ◽  
Pulsed Laser ◽  
Complex Oxides ◽  
Complex Oxide ◽  
Laser Deposition ◽  
Complex Structures ◽  
Layer By Layer ◽  
Oxide Nanorods ◽  
Layer Control

AbstractNanorods composed of complex oxides have been synthesized using hydrothermal and sol-gel methods, but pulsed-laser deposition (PLD) provides precise, layer-by-layer control of growth, and is the method of choice for synthesizing complex structures. However, producing complex-oxide nanorods by PLD has proved elusive.Here we report on our efforts to produce nanorods composed of the best-understood complex oxide, strontium titanate (STO). The results suggest it is indeed possible to produce STO nanorods via PLD by using a template of MgO nanorods.

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