• Title/Summary/Keyword: 고온자전합성

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Effect of Heating Rate on Self-Propagating, High-Temperature Synthesis of $TiAl_3$ Intermetallic from Multi-Layered Elemental Foils (다층원소박판에서 $TiAl_3$의 고온자전합성에 미치는 승온속도의 영향)

  • Kim, Yeon-Uk;Kim, Byeong-Gwan;Nam, Tae-Un;Heo, Bo-Yeong;Kim, Yeong-Jik
    • Korean Journal of Materials Research
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    • v.8 no.11
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    • pp.987-992
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    • 1998

  • Titanium aluminide intermetallic compound was formed from high purity elemental Ti and A1 foils by selfpropagating, high-temperature synthesis(SHS1 in hot press. Formation of $TiAl_3$ intermetallics at the interface between Ti and Al foil was observed to be controlled by temperature, pressure and heating rate. Especially, the heating rate is the most important role to form intermetallic compound by SHS reaction. According to DTA experiment, the SHS reactions appeared at two different temperatures below and above the melting point of Al. It was also observed that both SHS reaction temperatures increased with increasing the heating rate. After the SHS reaction of alternatively layered 10 Ti and 9 A1 foils at the heating rate of $20^{\circ}C$/min, the $700\mu\textrm{m}$ thick titanium aluminide sheet was formed by heat treatment at $810^{\circ}C$ for 4hours.

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Preparation and thermodynamics consideration of MgO-Al spinel by self-propagation high- temperature synthesis (자전고온연소합성법에 의한 MgO-Al 스피넬 제조 및 열역학적 고찰)

  • Byun, Hun-Soo;Choi, Tae-Hyun
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.8 no.4
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    • pp.573-580
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    • 1998

  • Self-propagating high temperature synthesis (SHS) technique was used to synthesize the spinel phase of $MgAl_2O_4$ from MgO and Al powder. Thermit reaction products of MgO and Al, The reaction products were heat treated at the temperature $800^{\circ}C$ preheating. Processing factors such as DTA/TG, combustium product and maxium temperature, synthesis of MgO and Al from "$MgO+2Al+3/2O_2$\rightarrow$MgAl_2O_4$". An activation energy (${\Delta}H^{\circ}$)-264.8 kcal/mol and reaction of maxium temperature 5634 K was calculated to form a $MgAl_2O_4$ spinel from unreacted materials. Pellet were increased volume 6% after thermit reaction. reaction.

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