• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 추계학술대회논문집
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• pp.89-92
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• 2004

This paper is concerned with the drawing process of Al-Si wire. In this study, the finite-element model established in previous work was used to analyze the effects of various forming parameters, which included the reduction in area, the semi-die angle, the aspect ratio and the inter-particle spacing of the Si in drawing processes. The finite-element results gave the consolidation condition. From the results of analysis, the effects of each forming parameter were determined. It is possible to obtain the important basic data which can be guaranteed in the fracture prevention of Al-Si wire by using FEM simulation.

• 한국광물학회지
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• 제21권1호
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• pp.27-35
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• 2008

천연 광물소재를 양이온 치환하여 환경개선재로 응용되고 있는 $Lumilite^{(R)}$의 원료 중 원광의 광물학적 특징을 분석하고 구성광물의 나노결정의 발달특징을 관찰하였다. 이를 위하여 편광현미경에 의한 조직관찰, XRD, SEM, FTIR, XRF 분석을 실시하였다. 구성 광물상은 클리높틸로라이트, 일라이트, 석영, 알바이트 사장석이며, 본 시료는 미립질의 치밀한 조직을 가지는 것이 특징이다. 나노결정의 크기는 $70{\sim}100\;nm$ 범위가 흔하면, 비교적 등립질 내지 반등립질로 구성된다. 나노결정들의 단면은 아원형 내지 완만한 각형이며, 나노결정의 표면에는 수 nm 크기의 원형돌기가 거의 균질하게 분포한다. 전시료의 화학조성은 $SiO_2$ $74.22{\sim}75.65\;wt.%$, $Al_2O_3$ $13.25{\sim}13.72\;wt.$, CaO $4.23{\sim}5.15\;wt.%$이며, 그 외 주성분과 수분은 미량으로 함유된다. 원료물질은 결정학적으로 $500^{\circ}C$까지는 안정한 상을 유지하나, $700^{\circ}C$에서는 구조가 거의 파괴된다. $Lumilite^{(R)}$가 흡착능력이 뛰어나고 높은 양이온치환능력을 가지는 것은 나노결정들이 잘 발달하고, 이들 사이에는 다양한 미세공극이 잘 발달하기 때문인 것으로 보인다.

• 한국세라믹학회지
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• 제35권1호
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• pp.97-105
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• 1998

20mol% Gd-doped CeO2 ultrafine powders as a promising electrolyte for the low temperature solid ox-ide fuel cells were synthesized with particle sizes of 15-20 nm using glycine nitrate process(GNP) fol-lowed by sintering their pellets at 150$0^{\circ}C$ for various times in air and then the electrical properties of the sintered pellets were investigated. The sintering behaviors and electrical properties for the sintered 20 sintered mol% Gd-doped CeO2 pellets were analyzed using dilatometer and SEM and AC two-terminal impedance technique respectively. As the heating temperature increased the synthesized powder had the sintering behaviors to show the start of the significant shrink at temperature of about $700^{\circ}C$ and to show the end of the shrink at the temperature of about 147$0^{\circ}C$. When the pellets were sintered with the vaious times at 150$0^{\circ}C$ the temperatuer which the shrink had been already completed the grain sizes in the sintered 20 mol% Gd-doped GeO2 pellets increased with the increase of the sintering time but their electrical resis-tivities showed the minimum value at the sintering time of 10h. It is due that the pellet sintered for 10h had the minimum activation energy fior the electtrical conduction. Thus it is thought that the decrease of the activation energy with the increase of the sintering time to 10h is induced by the enhanced mi-crostructure like the decrease of pore amount and the grain growth and its increase with the sintering times more than 10h is induced by the increase of the amounts of the impurities such as Mg. Al and Si from the sintering atmosphere.