• Journal of the Korean Ceramic Society
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• v.38 no.6
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• pp.545-550
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• 2001

본 연구에서는 분사연소합성(SCS)을 위한 기초단계로서 용액연소합성에 대한 거동을 살펴보고자 알루미나 합성을 모델로 하였으며 이를 위해 전구체에 대한 열분해거동, 그리고 각 온도에서의 평형종 분압 계산 및 합성과정을 조사하였다. 각각의 열중량 분석(TGA) 결과 산화제와 환원제(연료)의 열분해 이력이 서로 다르게 나타났으며, 열역학 응용 프로그램인 ChemSag에 의한 평형종 분압의 계산에서 연소속도를 저하시킬 수 있는 $CO_2$와 수증기 가스 분압이 상당부분 존재하였다. 산화제/환원제 혼합물의 열분석(DTA/TG) 결과 산화제와 환원제의 열분해 거동의 차이, 그리고 매우 작은 시료의 양으로 인해 263$^{\circ}C$에서 발열피크가 매우 작게 나타났다. 열분석 시료에 비해 발열 에너지를 높이기 위해 산화제와 환원제 혼합 전구체를 비이커에서 증기압을 조절하며 가열시켜 본 결과 27$0^{\circ}C$에서 $\alpha$-Al$_2$O$_3$생성물을 얻을 수 있었다. 따라서 분사연소합성 반응을 통해 세라믹 원료를 합성하기 위해서는 연소과정 중 열분해 거동과 평형종의 분압을 고려하여야 한다.

• Korean Journal of Materials Research
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• v.11 no.9
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• pp.797-801
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• 2001

In this study, the solution combustion method was employed to synthesize stoichiometric mullite, and hence the attrition process was employed to prepare ultrafine mullite particles with nano size. The thermal decomposition behavior and partial pressure of equilibrium species of both oxidizer and fuel were considered during solution combustion process. The synthesized product was mullite phase with 40 nm crystalline size, and the alumina contents of the product by TEM/EDS quantity analysis was 3.12$\pm$04 mole. The result showed that the synthesized mullite was almost close to the it's stoichiometric composition. For attrition process, the dispersion behavior of the mullite suspension was controlled and was comminuted with the condition of 800 rpm for 4 hours using 0.3 mm zirconia ball media. As a result of comminution, the mean particle size was 80 nm.

• Journal of the Korean Ceramic Society
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• v.39 no.1
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• pp.74-78
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• 2002

In this study, the solution combustion method was employed to synthesize perovskite PZT ceramics. Multicomponent oxides can be prepared by the solution combustion synthesis using redox exothermic reaction of precursor solutions. The results of DTA/TG showed exothermic peaks in 214$^{\circ}C$ and 350$^{\circ}C$. Those were caused by the differences of the thermal decomposition behavior of oxidizer and fuel. The combustion reaction was completed at 370$^{\circ}C$ during heating procedure, but the product was not transformed into perovskite. The thermal decomposition behavior of both oxidizer and fuel were considered during solution combustion process at 600$^{\circ}C$, which showed tetragonal single phase PZT ceramics with 50 nm crystalline size. The lattice constant a was 3.997 ${\pm}$ 0.001 ${\AA}$ and the lattice constant c was 4.147${\pm}$0.001 ${\AA}$.

• Proceedings of the Korean Ceranic Society Conference
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• 2000.04a
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• pp.95.1-95.1
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• 2000

• 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.

• Advances in materials Research
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• v.1 no.3
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• pp.191-204
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• 2012

In this paper, we report on the obtention of nanocrystalline $SrMoO_4$ synthesized through modified combustion process. These powders were characterized by X-ray diffraction, Fourier Transform Raman and Infrared Spectroscopy. These studies reveal that the scheelite-type $SrMoO_4$ crystallizes in tetragonal structure with I41/${\alpha}$ (N#88) space group. Transmission electron microscopy image shows that the nanocrystalline $SrMoO_4$ powders have average size of 18 nm. The optical band gap determined from the UV-V is absorption spectra for the as prepared sample is 3.7 eV. These powders showed a strong green photoluminescence emission. The samples are sintered at a relatively low temperature of $850^{\circ}C$. The morphology of the sintered pellet is studied with scanning electron microscopy. The dielectric constant and loss factor values obtained at 5 MHz for a well sintered $SrMoO_4$ pellet has been found to be 9.50 and $7.5{\times}10^{-3}$ respectively. Thus nano $SrMoO_4$ is a potential candidate for low temperature co-fired ceramics and luminescent applications.

• Journal of the Korean Ceramic Society
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• v.30 no.12
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• pp.1096-1102
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• 1993

Titanium nitride was synthesized by reacting Ti powder with nitrogen gas using SHS method. In this process, the effects of nitrogen pressure, dilution with TiN, or additiion of titanium hydride(TiH1.924) on the conversion of Ti to TiN were investigated. In particular, much effects were given to solve the problem of the conversion drop due to partial melting and subsequent sintering of Ti parciels, by controlling combustion temperature and combustion wave velocity via mixing Ti powder with TiN or/and TiH1.924. For the diluted titanium powders with TiN, the conversion close to 100% was resulted when the nitrogen pressure was over 8atm and with diluent content of 60wt%, and the self-propagating reaction was not sustained when the diluent content was higher than 60wt%. For samples mixed to be 55wt% in Ti component in the mixture of Ti, TiH1.924, and 45% TiN, the conversion was closed to 100% when the amount of titanium hydride added was over 7wt% and the nitrogen pressure was higher than 5atm. The combustion reaction, however, was not sustained when titanium hydride added was more than 10wt%.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.3
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• pp.209-219
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• 2019

Methanol is a liquid fuel which could also be produced from renewable energy sources and has appreciably high energy density. In this work, we investigated the application of $Ce_{0.9}Gd_{0.1}O_{2-x}$ supported Cu and Ni catalysts for hydrogen production via methanol steam reforming. Catalysts were synthesized by solution combustion synthesis. The prepared catalysts with various active materials and Cu loading amounts were tested in a reactor at $200-300^{\circ}C$, 0-5 barg range and steam to methanol molar ratio was 1.5. The catalytic properties of Cu and Ni were compared, and the catalytic performance was shown to depend on the amounts of metal loading and operating conditions such as reaction temperature and pressure.

• Nuclear Engineering and Technology
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• v.53 no.5
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• pp.1593-1601
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• 2021

Oxide dispersion strengthening (ODS) tungsten alloys are highly desirable in irradiation applications. However, how to improve the properties of ODS-tungsten alloys efficiently has been worth studying for a long time. Here we report a nanostructuring approach that achieves W-La₂O₃ alloy with a high level of flexural strength and Vickers hardness at room temperature, which have the maximum value of 581 MPa and 703 Hv, respectively. This method named solution combustion synthesis (SCS) can generate 30 nm coating structures W-La₂O₃ composite powders by using Keggin-type structural polyoxometalates as raw materials in a fast and low-cost process. The composite powder can be fabricated to W-La₂O₃ alloy with an optimal microstructure of submicrometric W grains coexisting with nanometric oxide particles in the grain interior, and a stability interface structure of grain boundaries (GBs) by forming transition zones. The method can be used to prepare new ODS alloys with excellent properties in the future.

• Transactions of the Korean hydrogen and new energy society
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• v.21 no.5
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• pp.452-459
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• 2010

This study is aimed to investigate changes of combustion characteristics and heat efficiency when syngas from gasification process using low-rank fuel such as waste and/or biomass is applied partially to an industrial boiler. An experimental study on syngas co-combustion was performed in a 0.7 MW (1 ton steam/hr) water tube boiler using heavy oil as a main fuel. Three kinds of syngas were used as an alternative fuel: mixture gas of pure carbon monoxide and hydrogen, syngas of low calorific value generated from an air-blown gasification process, and syngas of high calorific value produced from an oxygen-blown gasification process. Effects of co-combustion ratio (0~20%) for each syngas on flue gas composition were investigated through syngas injection through the nozzles installed in the side wall of the boiler and measuring $O_2$, $CO_2$, CO and NOx concentrations in the flue gas. When syngas co-combustion was applied, injected syngas was observed to be burned completely and NOx concentration was decreased because nitrogen-containing-heavy oil was partially replaced by the syngas. However, heat efficiency of the boiler was observed to be decreased due to inert compounds in the syngas and the more significant decrease was found when syngas of lower calorific value was used. However, the decrease of the efficiency was under 10% of the heat replacement by syngas.