• Journal of the Korean Ceramic Society
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• v.36 no.9
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• pp.974-981
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• 1999

• Journal of the Korean Ceramic Society
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• v.32 no.9
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• pp.1085-1091
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• 1995

Molybdenum disilicide (MoSi2) was synthesized from Mo, MoO3, Si and Al powders by self-propagating high temperature synthesis (SHS). The effect of processing parameters such as Mo/MoO3 molar ratio, Ar gas pressure in the reactor and pressing pressure of compacts in synthesis of MoSi2 were investigated. h-MoSi2 was transformed into t-MoSi2 with increasing the Mo/MoO3 mole ratio, and only t-MoSi2 phase was identified above 3.5 : 1 (molar ratio). The synthesized phases did not change with the variation of Ar gas pressure and pressing pressure of compacts. It was found that the combustion temperature was above 2,50$0^{\circ}C$. The products were separated into MoSi2 (s) and $\alpha$-Al2O3 by the difference of their specific grativities. Bending strength, hardness and density of sintered specimen exhibited 82 MPa, 5.368 GPa and 5.43 g/㎤, respectively.

• Journal of the Korean Ceramic Society
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• v.32 no.9
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• pp.1009-1018
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• 1995

(Ti.Si)C composite powders were synthesized by SHS method using microwave energy. Compositional and structural characterization of the powder were carried out by using scanning electron microscopy and X-ray diffraction. The average particle size of the synthesized (Ti.Si)C composite powders was smaller than that of the starting materials. From the results of the temperature profile, combustion temperature and velocity were decreased with increasing Si molar ratio. With increasing C molar ratio combustion temperature and velocity did not change. (Ti.Si)C composite was sintered at 185$0^{\circ}C$ for 60 min by using hot-pressing with 30 MPa. The best properties were obtained from the sintered specimen whose composition was 1 : 1 : 1.9 molar ratio of Ti : Si : C. The sintering density, flexural strength and vickers hardness of the sintered body were 4.71 g/㎤, 423 MPa and 21 GPa, respectively.

• Journal of the Korean Ceramic Society
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• v.42 no.7 s.278
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• pp.503-508
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• 2005

A simple and effective method for the synthesis of LiMn$_{2}$O$_{4}$ powder as a cathode material for lithium secondary battery is reported. Micrometer size LiMn$_{2}$O$_{4}$ was prepared by combustion synthesis technique employing initial mixture of l.l LiNO$_{3}$ -1.3Mn-0.7MnO$_{2}$-1NaCl composition. Parametric study of the combustion process including molar ratio of Mn/MnO$_{2}$ and NaCl concentration were carried out under air atmosphere. The combustion products obtained were additionally heat treated at the temperature 900$^{\circ}C$ and the washed by distilled water. The results of charging-discharging characteristics revealed that LiMn$_{2}$O$_{4}$ cell synthesized in the presence of NaCl had a high capacity and much better reversibility than one formed without NaCl An approximate chemical mechanism for LiMn$_{2}$O$_{4}$ formation is proposed.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.782-783
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• 2006

Titinium carbide $(TiC_x)$ was produced by self-propagating high temperature synthesis (SHS) method. The morphology and non-stoichiometric number of the SHS product were observed by scanning electron microscopy and neutron diffractometry, respectively. Tubular titanium carbide with hole inside was formed with different non-stoichiometric number (x), which value increased with combustion temperature.

• Journal of the Korean Ceramic Society
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• v.31 no.11
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• pp.1249-1258
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• 1994

Titanium carbide was synthesized by reacting the prepared titanium powder and carbon black using SHS method sustains the reaction spontaneously, utilizing heat generated by the exothermic reaction itself. In this process, the effect of the particle size of titanium powder on combustion temperature and combustion wave velocity was investigated. By controlling combustion temperature and combustion wave velocity via mixing Ti and C powder with TiC, the reaction kinetics of TiC formation by SHS method was considered. Without reference to the change of combustion temperature and combustion wave velocity, TiC was easily synthesized by combustion reaction. As the particle size of titanium powder was bigger, or, as the amount of added diluent(TiC) increased, combustion temperature and combustion wave velocity were found to be decreased. The formation of TiC by combustion reaction in the Ti-C system seems to occur via two different mechanisms. At the beginning of the reaction, when the combustion temperatures were higher than 2551 K, the reaction was considered to be controlled by the rate of dissolution of carbon into a titanium melt with an apparent activation energy of 148 kJ/mol. For combustion temperatures less than 2551 K, it was considered to be controlled by the atomic diffusion rate of carbon through a TiC layer with an apparent activation energy of 355 kJ/mol. The average particle size of the synthesized titanium carbide was smaller than that of the starting material(Ti).

• Korean Journal of Metals and Materials
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• v.47 no.6
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• pp.338-343
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• 2009

The purpose of this study is to make the tantalum powder for solid electrolyte capacitor with SHS (self-propagating high-temperature synthesis) process. Raw materials for manufacturing Ta powder were used $Ta_{2}O_{5}$, Mg and NaCl. While progressing SHS process, $Ta_{2}O_{5}$ powder was reduced by Mg powder. The combustion temperature and velocity were easily controled by the varying mole ratio of NaCl, Mg and initial reaction pressure. In the case of only using NaCl as an inorganic agent, the shape is unagglomerated and has high surface area. whereas we were given the powder which has good net structure by the addition of excessive Mg as a diluent.

• Journal of Powder Materials
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• v.20 no.5
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• pp.332-337
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• 2013

Recently, self-propagating high-temperature synthesis (SHS), related to metallic and ceramic powder interactions, has attracted huge interest from more and more researchers, because it can provide an attractive, energy-efficient approach to the synthesis of simple and complex materials. The adiabatic temperature $T_{ad}$ and apparent activation energy analysis of different thermit systems plays an important role in thermodynamic studies on combustion synthesis. After establishing and verifying a mathematic calculation program for predicting adiabatic temperatures, based on the thermodynamic theory of combustion synthesis systems, the adiabatic temperatures of the NiO/Al aluminothermic system during self-propagating high-temperature synthesis were investigated. The effect of a diluting agent additive fraction on combustion velocity was studied. According to the simulation and experimental results, the apparent activation energy was estimated using the Arrhenius diagram of $ln(v/T_{ad}){\sim}/T_{ad}$ based on the combustion equation given by Merzhanov et al. When the temperature exceeds the boiling point of aluminum (2,790 K), the apparent activation energy of the NiO/Al aluminothermic system is $64{\pm}14$ kJ/mol. In contrast, below 2,790 K, the apparent activation energy is $189{\pm}15$ kJ/mol. The process of combustion contributed to the mass-transference of aluminum reactant of the burning compacts. The reliability of the simulation results was experimentally verified.

• Korean Journal of Metals and Materials
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• v.50 no.6
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• pp.439-443
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• 2012

YAG:Ce phosphor were prepared in a self-propagating high-temperature synthesis (SHS) using a $1.5Y_2O_3+2.5Al_2O_3+0.116CeO_2+3.0KClO_3+kCO(NH_2)_2+m(C_2F_4)_n$ precursor mixture. The heat for the combustion propagation was provided by the reaction of a $KClO_3+CO(NH_2)_2+(C_2F_4)n$ mixture. Pure-phase YAG phosphor was synthesized at the combustion temperature of $1210^{\circ}C$ from k=3.6 mole and m=0.3 mole. The as-prepared YAG:Ce phosphor had a particle size of $2-10{\mu}m$. The addition of Teflon to the precursor mixture increased the YAG particle size and its luminescent intensity. The emission peak of the YAG phosphor was blue-shifted with an increase of Teflon concentration.

• The Korean Journal of Ceramics
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• v.5 no.2
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• pp.148-154
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• 1999

A method to simultaneously synthesize and consolidate $Ti_5Si_4 \;and\; Ti_5Si_3$-20 vol%Nb composite from powders of Ti, Si and Nb was investigated. Combustion synthesis was carried out under the combined effect of an electric field and mechanical pressure. Highly dense $Ti_5Si_4 \;and\; Ti_5Si_3$-20 vol% Nb with relative densities up to 98% was produced from powders of Ti, Si and Nb under the application of 60 MPa pressure and 3000A current on the reactant.