• The Korean Journal of Ceramics
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• 제6권3호
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• pp.250-257
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• 2000

The feasibility of synthesizing SiC-AlN solid solution by field-activated combustion synthesis was demonstrated. At lower fields of 8-16.5V/cm, composites of AlN-rich and SiC-rich phases were synthesized, but at fields of 25-30 V/cm, the product was a 2H structure solid solution. Combustion synthesis of the solid solution by nitridation of aluminum with silicon carbide under a nitrogen gas pressure of 4-8 MPa was also investigated. The maximum combustion temperature and wave propagation velocity were found to be influenced by the electric field in the field-activated combustion synthesis, and by the green density and nitrogen pressure in the combustion nitridation. In both cases the formation of solid solutions is complete within seconds, considerably faster than in conventional methods which require hours.

• 한국재료학회지
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• 제33권10호
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• pp.385-392
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• 2023

A solution combustion process for the synthesis of hollandite (BaAl₂Ti₆O₁₆) powders is described. SYNROC (synthetic rock) consists of four main titanate phases: perovskite, zirconolite, hollandite and rutile. Hollandite is one of the crystalline host matrices used for the disposal of high-level radioactive wastes because it immobilizes Sr and Lns elements by forming solid solutions. The solution combustion synthesis, which is a self-sustaining oxi-reduction reaction between a nitrate and organic fuel, generates an exothermic reaction and that heat converts the precursors into their corresponding oxide products in air. The process has high energy efficiency, fast heating rates, short reaction times, and high compositional homogeneity. To confirm the combustion synthesis reaction, FT-IR analysis was conducted using glycine with a carboxyl group and an amine as fuel to observe its bonding with metal element in the nitrate. TG-DTA, X-ray diffraction analysis, SEM and EDS were performed to confirm the formed phases and morphology. Powders with an uncontrolled shape were obtained through a general oxide-route process, confirming hollandite powders with micro-sized soft agglomerates consisting of nano-sized primary particles can be prepared using these methods.

• The Korean Journal of Ceramics
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• 제6권2호
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• pp.172-176
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• 2000

Solid solutions of Ti$_{0.5}$Zr$_{0.5}$B$_2$were successfully synthesized and densified simultaneously from elemental reactants by the use of a field-activated, pressure-assisted synthesis method. The method involves the application of an electric current and mechanical pressure across reactant compacts to achieve combustion synthesis. Dense solid solutions with relative densities of up to 99% were produced and characterized by XRD, SEM, and EPMA methods. With a maximum measured temperature of 145$0^{\circ}C$ under a load of 86 MPa for 30 min, the desired dense solid solution wad synthesized.

• 한국분말재료학회지
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• 제8권1호
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• pp.13-19
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• 2001

Ni and NiO particles were made by a combustion synthesis process. The characteristics of synthesized powders were investigated with various kinds and amounts of fuels such as urea, citric acid and glycine. Ni phase particles without NiO phase were obtained through combustion synthesis process in air atmosphere with-out further calcinations process, when the content of glycine was 2.44 times of the stoichiometric ratio in the precursor solution. Primary particle sizes of synthesized Ni and NiO particles were about 20∼30 nm.

• The Korean Journal of Ceramics
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• 제6권1호
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• pp.47-52
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• 2000

Lanthanides such as La, Gd and Ce have recognized as elements of high level radioactive wastes immobilized by forming solid solution with $CaTiO_3$. For easy forming solid solution between $CaTiO_3$and lanthanides, the combustion synthesis process was applied and the powder characteristics and sinterability were investigated. The proper selection of the type and the composition of fuels are important to get the crystalline solid solution of $CaTiO_3$and lanthanides. When glycine or the mixtures of urea and citric acid with stoichiometric composition was used as a fuel, the solid solution of $CaTiO_3$with $La_2O_3$or $Gd_2O_3$or $CeO_2$was produced very well by the combustion process. The combustion synthesized powder seemed to have a good sinterability with the linear shrinkage of more than 25% up to $1500^{\circ}C$, while that of the solid state reacted powder was less than 10% at the same condition.

• 한국세라믹학회지
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• 제53권1호
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• pp.122-127
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• 2016

Tin oxide ($SnO_2$) nanoparticles have been synthesized by solution combustion method using citric acid as a fuel. The oxide to fuel ratio has been varied to obtain ultrafine nanoparticles with better surface area; such particles will be useful in many applications. With this synthesis method, spherical particles are formed having a particle size in the range of 11-30 nm and BET surface area of ~ $24m^2/g$. The degree of agglomeration of $SnO_2$ nanoparticles has been calculated.

• 한국재료학회지
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• 제25권9호
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• pp.492-496
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• 2015

Hydroxyapatite (HA), which is an important calcium phosphate mineral, has been applied in orthopedics, dentistry, and many other fields depending upon its morphology. HA can be synthesized with different morphologies through controlling the synthesis method and several parameters. Here, we synthesize various morphologies of HA using two simple methods: hydrothermal combustion and solution combustion. The phase purity of the synthesized HA is confirmed using X-ray diffractometry. It demonstrates that pure phased hydroxyapatite can be synthesized using both methods. The morphology of the synthesized powder is examined using scanning electron microscopy. The effects of pH and temperature on the final powder are also investigated. At $140^{\circ}C$, using the hydrothermal method, nano-micro HA rods with a hexagonal crystal structure can be synthesized, whereas using solution combustion method at $600^{\circ}C$, a dense cubic morphology can be synthesized, which exhibits monoclinic crystal structures.

• 한국세라믹학회지
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• 제39권1호
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• pp.74-78
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• 2002

본 연구에서는 전구체 용액의 산화환원 발열반응을 이용하여 다성분계 산화물을 제조할 수 있는 용액연소합성법을 이용하여 페로브스카이트 구조 PZT 세라믹스를 합성하고자 하였다. 산화제/환원제 전구체 혼합물의 열분석(DTA/TG) 결과 산화제와 환원제의 열분해 거동의 차이로 인해 214$^{\circ}C$와 35$0^{\circ}C$에서 발열 피크가 나타났다. PZT세라믹스 합성을 위한 승온 과정에서는 37$0^{\circ}C$에서 연소반응이 일어났으나, 페로브스카이트로의 상전이는 일어나지 않았다. 용액연소과정 중 산화제와 연료의 열분해 거동을 고려하여 $600^{\circ}C$에서 제조한 생성물은 결정크기가 50nm인 정방정의 단일상으로 이루어진 PZT세라믹스이었다. 격자상수를 측정한 결과 a는 3.997$\pm$0.001 $\AA$이었으며, c는 4.147$\pm$0.001 $\AA$으로 나타났다.

• 한국재료학회지
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• 제18권6호
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• pp.313-317
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• 2008

[ $LaFeO_3$ ] powders were synthesized using a method involving solution combustion, and the surface properties of these powders were examined by x-ray photoelectron spectroscopy. As the amount of fuel increased during the synthesis, the $LaFeO_3$ powders became amorphous with a large plate-like shape. It was found that the O 1s spectra were composed of two types of photoelectrons by deconvolutioning the spectra. Photoelectrons with higher binding energy come from adsorbed oxygen ($O^-$) whereas those with lower energy come from lattice oxygen ($O^{2-}$). The ratio of adsorbed and lattice oxygen increased as the ratio of the fuel and nitrate (${\Phi}$) increased. The binding energy of both types of oxygen increased as ${\Phi}$ increased due to the formation of carbonates.

• 한국수소및신에너지학회논문집
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• 제30권3호
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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.