• Title/Summary/Keyword: Flame Synthesis

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Synthesis and Characteristics of Magnesium Hydroxide Group Flame Retardant for Polymer Addtives (고분자 첨가제인 난연제로서의 수산화마그네슘계 물질의 합성과 특성)

  • Lee, Dong-Kyu;Kang, Kuk-Hyoun;Lee, Jin-Hwa
    • Journal of the Korean Applied Science and Technology
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    • v.26 no.4
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    • pp.385-393
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    • 2009
  • Different types magnesium hydroxide groups have been obtained using the hydrothermal precipitation technique from magnesium sulfate and calcium carbonate solution. The Mg atom coordinated around O atom of ${SO_4}^{2-}$ in another layer to form a multi-layer structure crystal. The influence of synthesis parameters on the morphological characteristics and size of magnesium hydroxide groups precipitated in aqueous were investigated such as different of additive and pH. Magnesium hydroxide groups were decomposed gradually and converted finally to MgO particles after heated in air temperature up to $1050^{\circ}C$. The particle size and it's distribution morphology, crystal phase and thermal behavior of the samples were characterized through XRD, SEM, EDS, and TG/DTA.

Synthesis of $Bi_{2+x}Sr_2Ca_{n-1}Cu_{n}O_{4+2n+d}$ compounds by SHS

  • Soh, Deawha;Cho,Yongioon;Korobova, N.;Isaikina, O.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.07a
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    • pp.94-97
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    • 2002
  • BSCCO (2223) compound which has the highest temperature of transition to the superconducting state in the homologous series considered is synthesized by SHS. The method exploits self-sustaining solid-flame combustion reactions which develop very high internal material temperatures over short periods. This report introduces the SHS method and its advantages and discusses its application in the synthesis of superconducting materials.

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Effect of Silica Addition on Phase Transformation Characteristics of Heat-Treated Combustion-Synthesized TiO2 Nanoparticles (실리카가 첨가된 연소합성 TiO2 나노입자의 열처리에 따른 상변환 특성)

  • Kim, Min-Su;Lee, Gyo-Woo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.33 no.3
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    • pp.186-193
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    • 2009
  • In this article, the effect of silica addition on the phase transformation characteristics of $TiO_2$ nanoparticles synthesized by using an $O_2$-enriched coflow, hydrogen, diffusion flame was investigated. TTIP(titanium tetra-isopropoxide) and TEOS(tetraethyl-orthosilicate) were used as precursors for $TiO_2$ and $SiO_2$ nanoparticles, respectively. Based on the results from TEM and XRD analysis, it is believed that the silica addition on the flame synthesis of $TiO_2$ nanoparticles reduces the particle size distribution and raises the temperature of the phase transition from anatase to rutile. But the reduced sizes of the synthesized particles due to the silica addition made the sintering and phase transformation of particles more easily.

Studies on Synthesis of N,N’-Bis(diphenyl phosphoro)diaminohexane and Flame Retardancy Effects of BDPDH on PET Fabrics. (N,N’-Bis(diphenyl phosphoro)diaminohexane의 합성과 PET 직물에 대한 방염성에 관한 연구)

  • Lee, Kwang-Woo;Heo, Man-Woo;Yoon, Jong-Ho;Lee, Chang-Sub;Cho, Yong-Seok;Kim, Sam-Soo;Cho, Hwan
    • Textile Coloration and Finishing
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    • v.6 no.2
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    • pp.55-62
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    • 1994
  • The mend for fabric products has been increased remarkably with increasing population, housings, mutistory buildings,...and etc. during the last two decades. However, since fabrics are highly combustible and can produce toxic gases during the combution, fabric products can result in serious human injury as well as financial damage. Acknowledged by this, a new phosphorus based flame retardant suitable for PET fabric has been synthesized by making use of the reaction of diphenyl chloro phosphate and hexamethylenediamine. Since the starting meterials are relatively cheap and the yield of this reaction is high (more than 90%), this reaction seems to be very effective as wall as very economic. By analyzing various spectrophotometric analysis data such as NMR, FT-IR, and Mass, this new flame retardant is identified to be N,N’-Bis(diphenyl chlorophosphoro)diamino hexane. In the mean time, DSC measurement has shown that the melting point and the boiling point of this material are around 115$^{\circ}C$ and around 40$0^{\circ}C$, respectively. The flame retardancy test done on the PET fabric processed by this flame retardant have shown excellent in times of flame contact, times of flame contact for washable. The most economical finishing condition estimated 10% in concentration of BDPDH, Moreover, it has been also found that the drape stiffness of the PET fiber processed by the flame retartant is changed very litter compared to the unprocessed original PET fabrics. Judging from this, the potential of this new phosphrdus based compond as a flame retardant for PET fabric seems to be high.

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Fabrication of Transition-metal-incorporated TiO2 Nanopowder by Flame Synthesis (화염법에 의한 천이금속 첨가 이산화티타늄 나노분말의 제조)

  • Park Hoon;Jie Hyunseock;Lee Seung-Yong;Ahn Jae-Pyoung;Lee Dok-Yol;Park Jong-Ku
    • Journal of Powder Materials
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    • v.12 no.6 s.53
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    • pp.399-405
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    • 2005
  • Nanopowders of titanium dioxide $(TiO_2)$ incorporating the transition metal element(s) were synthesized by flame synthesis method. Single element among Fe(III), Cr(III), and Zn(II) was doped into the interior of $TiO_2$ crystal; bimetal doping of Fe and Zn was also made. The characteristics of transition-metal-doped $TiO_2$ nanopowders in the particle feature, crystallography and electronic structures were determined with various analytical tools. The chemical bond of Fe-O-Zn was confirmed to exist in the bimetal-doped $TiO_2$ nanopowders incorporating Fe-Zn. The transition element incorporated in the $TiO_2$ was attributed to affect both Ti 3d orbital and O 2p orbital by NEXAFS measurement. The bimetal-doped $TiO_2$ nanopowder showed light absorption over more wide wavelength range than the single-doped $TiO_2$ nanopowders.

Simulation of the Growth of Non-Spherical Particles in a Counterflow Diffusion Flame (대향류 확산 화염 중에서 비구형 입자 성장에 관한 해석)

  • Jeong, Jae In;Hwang, Jun Young;Lee, Bang Weon;Choi, Mansoo;Chung, Suk Ho
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.23 no.8
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    • pp.997-1009
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    • 1999
  • Silica particle formation and growth process including chemical reaction, coagulation and sintering was studied in a counterflow diffusion flame burner. The counterflow geometry provides a one dimensional flow field, along the stagnation point streamline, which greatly simplifies interpretation of the particle growth characteristics. $SiCl_4$ has been used as the source of silicon in hydrogen/oxygen/argon flames. The temperature profiles obtained by calculation showed a good agreement with experiment data. Using one and two dimensional sectional method, aerosol dynamics equation in a flame was solved, and these two results were compared. The two dimensional section method can consider sintering effect and growth of primary particle during synthesis, thus it showed evolution of morphology of non-spherical particles (aggregates) using surface fractal dimension. The effects of flame temperature and chemical loading on particle dynamics were studied. Geometric mean diameter based on surface area and total number concentration followed the trend of experiment results, especially, the change of diameters showed the sintering effect in high temperature environment.