• 제목/요약/키워드: Reactive Spray Forming

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분무성형 및 반응분무성형법으로 제조된 분산강화 동합금의 항복강도에 미치는 분산상의 영향 (The Effect of Dispersoid on Yield Strength of Dispersion Strengthened Cu Alloys Fabricated by Spray Forming and Reactive Spray Forming)

  • 이종상;정재영;이언식;박우진;안상호;김낙준
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 1999년도 압출 및 인발 심포지엄
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    • pp.38-46
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    • 1999
  • Dispersion strengthened Cu alloys have been manufactured by spray forming and also by reactive spray forming, followed by hot extrusion of the spray deposited billets. The size of dispersed particles in the reactive spray formed alloy was much finer than that in the spray formed alloy. That was because the dominant chemical reaction between Ti and B had occurred in Cu-Ti-B alloy melt in spray forming while it had occurred after deposition of droplets in reactive spray forming. The yield strength of the reactive spray formed alloy was greater than that of the spray formed alloy. To understand the mechanism responsible for this observed strengthening, the yield strength of two Cu alloys were analyzed using the dislocation pile-up model and Orowan mechanism, which were fairly consistent with the experimental results. Increase in yield strength of reactive spray formed alloy relative to spray formed alloy was largely attributed to nano-scale TiB dispersoids.

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규소의 질화반응에 있어 산화마그네시움의 효과 (Effect of Magnesium Oxide on the Nitridation of Silicon Compact.)

  • 박금철;최상원
    • 한국세라믹학회지
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    • 제20권4호
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    • pp.305-314
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    • 1983
  • In order to enhance the rate of th nitridation and to give the high density of reaction-bonded silicon nitride MgO powder as nitriding aid were added to silicon powders and the mixture was pressed isostatically into compacts which were nitrided in the furnace of 1, 35$0^{\circ}C$ where 95% $N_2$-5% $H_2$ gases were flowing. As the other nitriding aid $Mg(NO_3)_2 6H_2O$ was selected, A slip made of magnesium nitrate solution and fine silicon particles was spray-dried and then decomposed at 30$0^{\circ}C$. Magnesium oxide-coated silicon powders were formed into compacts prior to the nitridation on the same condition as the former. Magnesium nitrate (MgO, produced from the decomposition of magnesium nitrate) was more effective for the formation of the $\beta$-phase in the initial stage of the nitridation probably due to the easy formation of $MgO-SiO_2$-metal oxide eutectic melt. It has been confirmed that forsterite was formed as a result of the reaction between MgO and $SiO_2$ film of silicon surface. It was considered that MgO produced from magnesium nitrate may be finer more reactive and more uniformly distributed on the surface of silicon particles than original MgO. The higher the forming pressure was the more the $\beta$-phase was formed.

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