• Title/Summary/Keyword: self propagating synthesis

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Fabrication of $SrZrO-3$-based Proton Conductors and Their Characterization

  • Yoo, Kwang-Soo;Byun, Douck-Young
    • The Korean Journal of Ceramics
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    • v.7 no.2
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    • pp.93-96
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    • 2001
  • The Y- or Yb-doped SrZrO$_3$ proton conductors were fabricated using the powders prepared by the self-propagating high-temperature synthesis (SHS). The electrical conductivity was evaluated from an a.c. impedance measurements. The conductivity of SrZr$_{0.92}$Yb$_{0.08}$O$_{3-\delta}$ was 1.8$\times$10$^{-3}$ Scm$^{-1}$ at $900^{\circ}C$ in dry air atmosphere and its activation energy was 0.50 eV. The conductivity in wet air was larger, compared with the dry air, and the activaton energy of SrZr$_{0.92}$Yb$_{0.08}$O$_{3-\delta}$ in wet air was 0.40 eV.

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Chromate Refractory by Combustion Process (연소합성에 의한 크로메이트 내화물 제조)

  • 김형순;한정환
    • Journal of the Korean Ceramic Society
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    • v.31 no.12
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    • pp.1437-1442
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    • 1994
  • Self propagating synthesis and thermal explosion of combustion reactions were applied to Al/K2Cr2O7/Al2O3 system as the first stage for a production of magnesia-chromium refractory. Several factors related to products made by two combustion reactions were considered and properties of products were characterised. Two processes were required to preheat upto at least 80$0^{\circ}C$ for the thermal explosion and the self propagating synthesis. These processes were so violent and explosive that alumina as diluent was added to the system in order to absorb the reaction heat and reduce the reaction rate. The products consisted of crystal phases of KAl5O8, Cr2O3, Al2O3, K2CrO4, and K2Al2O4.3H2O. The amount of KAl5O8 and K2Al2O4.3H2O crystal phases of products were decreased with further addition of alumina.

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Properties of Hot Pressed Alumina-Titanium Diboride Particulate Composites

  • Park, Dong-Soo;Han, Byung-Dong
    • The Korean Journal of Ceramics
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    • v.4 no.3
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    • pp.227-230
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    • 1998
  • Alumina($Al_2O_3$)-Titanium Diboride($TiB_2) particulate composites were fabricated by hot pressing of the powder mixture that was prepared from Self-propagating High Temperature Synthesis (SHS) product and commercial powders. Their propeties were examined in order to find feasibility of using SHS for making the high performance ceramic composite. $TiB_2 particles obtained by grinding the SHS product were finer than the commercial powders. Hot pressed sample containing the SHS products exhibited higher strength than the one prepared from the commercial powders.

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A Study on the Synthesis of Titanium Hydride by SHS(Self-propagating High-temperature Synthesis) Method and the Preparation of Titanium Powder (SHS법에 의한 티타늄 수소화물 합성 및 티타늄 분말 제조에 관한 연구)

  • Ha, Ho;Park, Seung-Soo;Lee, Hee-Cheol
    • Applied Chemistry for Engineering
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    • v.5 no.2
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    • pp.263-273
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    • 1994
  • Titanium powder prepared by dehydrogenating the titanium hydride which is synthesized by reacting Ti-sponge (99.67%) with hydrogen using the self-propagating high-temperature synthesis method. In the synthesis of titanium hydride, the particle size of the product was found dependent on the amount of hydrogen incorporated into the titanium such that the particle size of titanium hydride decreased with increasing hydrogen pressure and after-burn time. In the dehydrogenation process, as the dehydrogenation time increase, the particle size of titanium powder increased due to partial melting and sintering of titanium particles.

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