• Title, Summary, Keyword: solid state reaction

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Synthesis of $Cu_2ZnSnSe_4$ compound by solid state reaction using elemental powders

  • Wibowo, Rachmat Adhi;Alfaruqi, Muhammad H.;Jung, Woon-Hwa;Kim, Kyoo-Ho
    • 한국신재생에너지학회:학술대회논문집
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    • pp.134-137
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    • 2009
  • Commercially available elemental powders of Cu, Zn, Sn and Se were employed for crystallizing a stannite-type $Cu_2ZnSnSe_4$ compound by means of solid state reaction. $Cu_2ZnSnSe_4$ reaction chemistry was also modeled based on differential-thermal analysis and X-ray powder diffraction results. It was observed that Se tends to react preferably with Cu to form CuSe and $CuSe_2$ phases at low reaction temperature. The formation of $Cu_5Zn_8$ intermetallic phase was found to be the intermediate reaction path for the binary ZnSe formation. A solid state reaction at $320^{\circ}C$ reacted elemental powderst obinary selenides of CuSe, ZnSe and SnSe completely. The crystallization of $Cu_2ZnSnSe_4$ was was detected to begin at $300^{\circ}C$ and its weight fraction increased with an increase of reaction temperature, which most probably formed from the reaction between $Cu_2SnSe_3$ and ZnSe.

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Synthesis and Hydration Property of 3CaO.${3Al_2}{O_3}$.$CaSO_4$ Clinker by Solid State Reaction (고상반응에 의한 3CaO.${3Al_2}{O_3}$.$CaSO_4$ 클링커의 제조 및 수화)

  • 전준영;김형철;조진상;송종택
    • Journal of the Korean Ceramic Society
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    • v.37 no.5
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    • pp.459-465
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    • 2000
  • 3CaO.3Al2O3.CaSO4(C4A3)clinker was prepared by solid state reaction and then its hydration property was investigated. C4A3 clinker was fired at various temperatures in the range of 700~135$0^{\circ}C$. The hydration of it was studied by XRD, DSC, Solid-state 27Al MAS NMR and SEM. According to the results, the Ca4A3 clinker was produced by reacting calcium aluminates with CaSO4 and Al2O3 and C4A3 was formed as a main phase after calcining at 120$0^{\circ}C$. The hydration products were mainly calcium monosulfoaluminate hydrate and Al(OH)3, and they were produced after 2hrs of hydration. However the hydration rate was about 74% at 3days.

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Synthesis of Solid Electrolyte Nasicon by Solid State Reaction

  • Kim, Cheol-Jin;Chung, Jun-Ki;Lim, Sung-Ki;Rhee, Meung-Ho
    • The Korean Journal of Ceramics
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    • v.2 no.1
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    • pp.25-32
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    • 1996
  • Solid electroyte nasion was synthesized by the optimized solid state reaction minimizing the volume fraction of secondary $ZrO_2$ and glassy phases. To compensate for the evaporation of Na and P during heat-treatment, excess Na and P were added to the starting composition $Na_{1+x} Zr_2 Si_x P_{d-x} O_{12}$ (x=2.1). Phases pure nasicon comparable in volume fraction to the one obtaied from sol-gel process were synthesized after the reaction at $1100~1150^{\circ}C$,$ P_{O2}>=0.1-0.15 $$ZrO_2$ increased with the heat-treatment time due to the decomposition of nasicon phase and that of glassy phase increased as partial oxygen pressure decreased. The synthesized nasion showed a good electrical conductivity of $-1{\times}10^{-2}({\omega}{\cdot}cm)^{-1}$ at $350^{\circ}C$.

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The SrLiAl3N4:Eu2+ Phosphor Synthesized by the Raw Material Model Obtained by DFT Calculations

  • Park, Woon Bae
    • Journal of the Korean Ceramic Society
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    • v.54 no.3
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    • pp.217-221
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    • 2017
  • Improvement studies of existing phosphors are needed for use in light emitting diodes (LEDs). Among the phosphors discovered recently, the SLA ($SrLiAl_3N_4:Eu^{2+}$) is a phosphor that has a narrow width. It is now known as a good red phosphor that meets the industry's needs for warm white (color temperature ranging from 2700 to 4000 K) and high CRI (> 80). However, SLA phosphors are obtained from difficult synthetic methods. All commercially available phosphors should be derived from the general solid state synthesis method. The phosphors produced by difficult synthetic methods will inevitably fall out of price competitiveness and will be scrapped. This study succeeded in synthesizing SLA ($SrLiAl_3N_4:Eu^{2+}$) phosphors by using a general solid phase synthesis method based on the reaction energy obtained from DFT calculations. As a result, we found an optimal solid state synthesis method for SLA phosphors.

Synthesis of Zn4Sb3 by Solid State Reaction and Hot Pressing, and Their Thermoeletric Properties (고상 합성과 진공 압축성형에 의한 Zn4Sb3의 제조 및 열전특성)

  • Ur Soon-Chul
    • Korean Journal of Materials Research
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    • v.15 no.7
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    • pp.473-479
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    • 2005
  • Thermoelectric $Zn_4Sb_3$ alloys were synthesized by a conventional powder metallurgy process consisting of solid state reaction and hot pressing. Single phase $Zn_4Sb_3$ was successfully produced by the annealing of cold compact starting with the mixed elemental powders, and subsequent hot pressing yielded single phase bulk specimens without microcracks. Phase transformations in this alloy system during synthesis were investigated using XRD, SEM and EDS. Thermoelectric properties as a function of temperature were investigated from room temperature to 600 K and compared with results of analogue studies. Transport properties at room temperature were also evaluated. Thermoelectric properties of single phase $Zn_4Sb_3$ materials produced by this process are comparable to the published data. Synthesis by solid state reaction and hot pressing offers a potential processing route to produce a bulk $Zn_4Sb_3$

Structural and Magnetic Properties of Ni0.6Zn0.4Fe2O4 Ferrite Prepared by Solid State Reaction and Sol-gel

  • Kwon, Yoon Mi;Lee, Min-Young;Mustaqima, Millaty;Liu, Chunli;Lee, Bo Wha
    • Journal of Magnetics
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    • v.19 no.1
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    • pp.64-67
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    • 2014
  • $Ni_{0.6}Zn_{0.4}Fe_2O_4$ prepared using solid state reaction and sol-gel methods were compared for their structural and magnetic properties. Due to the much higher annealing temperature used in solid state reaction, the crystalline size was much larger than that of the nanoparticles prepared by sol-gel. The saturation magnetization of sol-gel nanoparticles was higher, and the coercivity was about 2 times larger, compared to the solid state reaction sample. By analyzing the integration intensity of x-ray diffraction peaks (220) and (222), we proposed that the difference in the saturation magnetization might be due to the inversion of cation distribution caused by the different preparation techniques used.

Feasibility of Recycling Residual Solid from Hydrothermal Treatment of Excess Sludge

  • Kim, Kyoung-Rean;Fujie, Koichi;Fujisawa, Toshiharu
    • Environmental Engineering Research
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    • v.13 no.3
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    • pp.112-118
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    • 2008
  • Residual solid in excess sludge treated by hydrothermal reaction was investigated as raw material for its recycling. Treated excess sludge and residual solid were also focused on their content change during hydrothermal reaction. Two kinds of excess sludge, obtained from a local food factory and a municipal wastewater treatment process, were tested under various conditions. Following hydrothermal reaction, depending on the reaction conditions, biodegradable substrates in treated excess sludge appeared to increase. The separated residual solid was a composite composed of organic and inorganic materials. The proportion of carbon varied from 34.0 to 41.6% depending on reaction conditions. Although 1.89% of hazardous materials were detected, SiO2 (Quartz) was a predominant constituent of the residual solid. X-ray diffraction (XRD) experiments revealed that the residual solid was of a partially amorphous state, suggesting that the residual solids could be easily converted to stable and non harmful substances through a stabilization process. Thus, this technology could be successfully used to control excess sludge and its reuse.

Studies on the fabrication and properties of $La_ 0.7Sr_0.3MnO_3$cathode contact prepared by glycine-nitrate process and solid state reaction method for the high efficient solid oxide fuel cells applications 0.3/Mn $O_{3}$ (고효율 고체산화물 연료전지 개발을 위한 자발 착화 연소 합성법과 고상반응법에 의한 $La_ 0.7Sr_0.3MnO_3$ 양극재료 제조 및 물성에 관한 연구)

  • Shin, Woong-Shun;Park, In-Sik;Kim, Sun-Jae;Park, Sung
    • Electrical & Electronic Materials
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    • v.10 no.2
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    • pp.141-149
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    • 1997
  • L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ powders were prepared by both GNP(Glycine-Nitrate Process) and solid state reaction method in various of calcination temperature(800-1000.deg. C) and time in air. Also, L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ cathode contacts on YSZ(Yttria-Stabilized Zirconia) substrate were prepared by screen printing and sintering method as a function of sintering temperature(1100-1450.deg. C) in air. Sintering behaviors have been investigated by SEM(Scanning Electron Microscope) and porosity measurement. Compositional and structural characterization were carried out by X-ray diffractometer and ICP AES(Inductively Coupled Plasma-Atomic Emission Spectrometry) analysis. Electrical characterization was carried out by the electrical conductivity with linear 4 point probe method. As the calcination period increased in solid state reaction method, L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ phase increased. Although L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ single phase was obtained only for 48hrs at 1000.deg. C, in GNP method it was easy to get single and ultra-fine L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ powders with submicron particle size at 650.deg. C for 30min. The particle size and thickness of L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ cathode contact by solid state reaction method did not change during the heat treatment, while those by GNP method showed good sintering characteristics because initial powder size fabricated from GNP method is smaller than that fabricated from solid state reaction method. Based on enthalpy change from thermodynamic data and ICP-AES analysis, it was suggested to make cathode contact in composition of (L $a_{0.7}$S $r_{0.3}$)$_{0.91}$ Mn $O_{3}$ which have little second phase (L $a_{2}$Z $r_{2}$ $O_{7}$) for high efficient solid oxide fuel cells applications. As (L $a_{0.7}$S $r_{0.3}$)$_{0.91}$Mn $O_{3}$ cathode contact on YSZ substrate was sintering at 1250.deg. C the temperature that liquid phase sintering did not occur. It was possible to obtain proper cathode contacts with electrical conductivity of 150(S/cm) and porosity content of 30-40%.m) and porosity content of 30-40%.

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Crystallizations of Fluoro-Phlogopite (불소운모의 결정화)

  • 송경근;오근호;이경희
    • Journal of the Korean Ceramic Society
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    • v.19 no.2
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    • pp.109-114
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    • 1982
  • Fluoro-phlogopite crystals (Mica) were synthesized by two different methods; firstly the crystal was crystallized from the melts, and secondly mica crystalline was obtained from the direct solid state reaction. Addition of $CaF_2$ in the mica batch revealed the lowering the solid state reaction temperature. SEM and XRD were employed to observe mica crystalline flakes and solid solution forms. As a starting raw material Pyrophyllite was used resulting in the formation of mica crystals.

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Synthesis of 100 nm BaTiO3 by Solid-state Reaction (고상법에 의한 100 nm BaTiO3 분말의 합성)

  • Kim, Jung-Hwan;Jung, Han-Seong;Cho, Joon-Yeob;Hong, Jeong-Oh;Kim, Young-Tae;Hur, Kang-Heon
    • Journal of the Korean Ceramic Society
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    • v.46 no.2
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    • pp.170-174
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    • 2009
  • $BaTiO_3$ powder was synthesized by the solid-state reaction of fine $BaTiO_3$ and $TiO_2$ raw materials. Fine grinding media of 50 and 300 microns were used for obtaining fine particulate mixture of $BaTiO_3$ and $TiO_2$ with high homogeneity. Effect of the size of grinding media on the synthesis mechanism of $BaTiO_3$ was discussed on the basis of the particulate morphology and thermogravimetry data for the mixture powders. By using the finer grinding media, $BaTiO_3$ was formed at the lower temperature and the particle size with the relatively narrower distribution could be obtained. $BaTiO_3$ powder with the average size of 100 nm was synthesized by the solid reaction in vacuum atmosphere.