• Title, Summary, Keyword: Self-Propagating High-temperature synthesis(SHS)

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A Study on Self-Propagating High-Temperature Synthesis of TiC-Ni-Mo Based Cermet (SHS공정에 의한 TiC-Ni-Mo 분말 합성 및 소결체 제조)

  • 송인혁;전재호;한유동
    • Journal of the Korean Ceramic Society
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    • v.35 no.7
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    • pp.749-756
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    • 1998
  • TiC-Ni and TiC-Ni-Mo cermet powders were produced by Self-propagating High temperature Synthesis (SHS) process. The cooling rate of synthesized powders were controlled by using the V-shaped copper jig and the carbide size decreased with increasing the cooling rate I. e decreasing the width of copper jig Round shape carbide particles were produced after SHS reaction in TiC-Ni as well as TiC-Ni-Mo powders. Local segregation of Mo rich phases was observed in SHS powder of TiC-Ni-Mo and the uneven dis-triobution of Mo promoted the faster growth rate of carbide particles during sintering compared to the same composition specimen with commercial TiC powder. Howogeneous microstructure of TiC-Ni-Mo cermet was obtained when the elemental Mo powder was mixed with the SHS powder of TiC-Ni.

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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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Sintering of $Si_3N_4$ Powder Prepared by Self-Propagating High-Temperature Synthesis (SHS)

  • Bai, Ling;Zhao, Xing-Yu;Ge, Chang-Chun
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • pp.268-269
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    • 2006
  • Preparation processing of sintered silicon nitride ceramics was emphatically investigated with Self-Propagating High-Temperature Synthesis (SHS) of silicon nitride prepared by ourselves as raw material. The results indicate that good sinter ability can be obtained with cheaply SHS of silicon nitride preparing silicon nitride materials. The cost of silicon nitride materials will be lowered.

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Simultaneous Consolidation of Titanium Diboride with Self-Propagating High-Temperature Synthesis, Direct Contact-Heating, and Pressure: Modeling of Temperature Distribution and the Relationship between Applied Energy and Densification ($TiB_2$ SHS 및 직접 접촉가열에 의한 동시 가압법 : 온도분포 모델링 및 공급에너지와 치밀화 관계)

  • Chung, G.K.;Cho, K.;Lee, H.B.
    • Journal of the Korean Ceramic Society
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    • v.32 no.7
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    • pp.817-824
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    • 1995
  • TiB2 was simultaneously synthesized and densified with concurrent self-propagating high-temperature synthesis and direct contact-heating by electrcial power input and pressure. Density of TiB2 synthesized by self-propagating high-temperature synthesis and consolidated simultaneously by direct contact-heating and pressure was maximum 80% of the theoretical density (4.52g/㎤). Temperature profile was analyzed by solving heat balance equation with numerical method (FTCS method). The temperature of the sample was sufficiently raised to that temperature sufficient to be densified. It was ascertained that the density of the SHS synthesized TiB2 is exponentially proportinal to the input thermal energy per mass.

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Fabrication of Porous TiNi Alloys by Self-propagating High-temperature Synthesis (자전연소반응에 의한 TiNi 다공체 합금 제조에 관한 연구)

  • 이상진;권대환;배승열;안인섭;김유영
    • Journal of Korean Powder Metallurgy Institute
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    • v.9 no.2
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    • pp.96-102
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    • 2002
  • In the present study, equiatomic porous TiNi shape-memory alloys have been successfully prepared by self-propagating high-temperature synthesis (SHS) using elemental titanium and nickel powders. The porous TiNi alloys thus obtained have an open porous structure with about 64 vol.% porosity, and the pore size is about 1.8 mm. The effect of preheating temperature on the microstructure have been investigated. It is found that the pore size increases with increasing preheating temperature. Moreover, the preheating temperature was shown to have a significant effect on the microstructrue of the SHS-synthesized porous TiNi shape memory alloys.

A Study on the Behavior of Combustion Wave Propagation and the Structure of Porous TiNi Body during Self-propagating High-temperature Synthesis Process

  • Kim, Ji-Soon;Gjuntera, Victor E.;Kim, Jin-Chun;Kwon, Young-Soon
    • Journal of Korean Powder Metallurgy Institute
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    • v.17 no.1
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    • pp.29-35
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    • 2010
  • We produced cylindrical porous TiNi bodies by Self-propagating High-temperature Synthesis (SHS) process, varying the heating schedule prior to ignition of a loose preform compact made from (Ti+Ni) powder mixture. To investigate the effect of the heating schedule on the behaviour of combustion wave propagation and the structure of porous TiNi shape-memory alloy (SMA) body, change of temperature in the compact during SHS process was measured as a function of time and used for determining combustion temperature and combustion wave velocity. Microstructure of produced porous TiNi SMA body was observed and the results were discussed with the combustion characteristics. From the results it was concluded that the final average pore size could be controlled either by the combustion wave velocity or by the average temperature of the preform compact prior to ignition.

Combination of MCA and SHS for Material Synthesis

  • Soh, Dea-Wha;N., Korobova
    • Journal of the Speleological Society of Korea
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    • no.78
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    • pp.1-8
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    • 2007
  • The combination of mechano-chemical activation (MCA)and Self-propagating High-temperature Synthesis (SHS) has widened the technical possibilities for both methods. For YBCO systems the investigation showed that a short-term MCA of initial powders before SHS leads to single-phase and ultra-fine products. A new technique for preparation ultra-fine high-temperature superconductors (HTS) of YBCO composition with a grain size d <1m is developed using combination of MCA and SHS. The specific feature of the technique is formation of the $YBa_2Cu_3O_7-$ crystalline lattice directly from an X-ray amorphous state arising as a result of mechanical activation of the original oxide mixture. The technique allows the stage of formation of any intermediate reaction products to be ruled out. X-ray and magnetic studies of ultra-fine high temperature superconductors are carried out. Dimension effects associated with the microstructure peculiarities are revealed. A considerable enhancement of inter-grain critical currents is found to take place in the ultra-fine samples.

Preparation of Titanium Carbide Fiber-Reinforced Alumina Ceramic Matrix Composites by Self-Propagating High-Temperature Synthesis

  • Yun, Jondo;Bang, Hwancheol
    • The Korean Journal of Ceramics
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    • v.4 no.3
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    • pp.171-175
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    • 1998
  • $Al_2O_3$-TiC composites were prepared from aluminum, titanium oxide, and carbon fibers by self-propagating high-temperature synthesis(SHS). After the SHS reaction, the TiC phase in the sample was found either fibrous or non-fibrous shape. The fraction of the fibrous TiC phase varied with the amount of $Al_2O_3$ diluent addition. The optimum amount of diluent to make fibrous carbide was determined to be 30%. The fibers were hollow inside and made of multiple grains with a composition of titanium carbide. The hollow fiber formation mechanism was suggested and discussed. The synthesized powders were consolidated to dense composites by hot pressing at $1750^{\circ}C$ under 30 MPa.

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Peculiarities of SHS and Solid State Synthesis of ReBa2Cu3O7-x Materials

  • Soh, Deawha;Natalya, Korobova
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.15 no.3
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    • pp.275-280
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    • 2002
  • The peculiarities of using Self-propagating High-temperature Synthesis (SHS) and solid-stave chase synthesis for production of high temperature superconductor materials were discussed. Oxide superconductors with general formula of $ReBa_2Cu_3O_{7-x}$ (Re=Y, Sm) haute been made by using barium oxide initial powder instead of traditional barium carbonate. Phenomena observed during the grinding of the reactants mixture are presented. Mechano-chemical activation - as a pre-treatment of the reactants mixture - strongly influences the kinetic parameters, the reaction mechanism, and the composition and structure of the final product.

Finite Element Analysis of the Self-propagating High-temperature Synthesis Of $MoSi_2$ ($MoSi_2$ 자전 고온 반응 합성의 유한 요소 해석)

  • 채수원;손창현;김용석
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.12
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    • pp.120-127
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    • 1998
  • The finite element method has been used to model and analyze the heat transfer phenomena during manufacturing process of $MoSi_2$ by SHS(Self-propagating High-temperature Synthesis). For this purpose nonlinear transient heat transfer analyses by using ANSYS have been performed to estimate the temperature distributions and the peak temperature in the test specimen. The effects of manufacturing process parameters such as pre-heating temperatures, the velocity of reaction zone have been investigated. The results of the analysis have been compared with the experimental results.

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