• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.221-223
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• 1999

In this work, samples were manufactured variously by changing conventional calcining and sintering conditions and we tried the utilization by making the heat treatment time, which is demanded to high-Tc phase formation, much shorter. We found out optimal heat treatment conditions with the analysis on formation process at superconducting phase in term of the change of calcining and sintering time and then, examined X-ray diffraction(XRD) patterns, scanning electron microscope(SEM) measurement and energy dispersive X-ray spectrometer(EDX) of the samples manufactured under heat treatment conditions which we suggest here. As a result, 2223 high-$T_c$, phase of (Bi,Pb)SrCaCuO superconductor starting with ($Bi_l$ xPbx,)$_2$$Sr_2$$Ca_2$$Cu_3$$O_y$, composition was formed from 1 hr sintering sample at temperature nearby melting point and also the completed sample with calcining and sintering time of 9 hr was formed high-$T_c$.low-$T_c$ phase appearing in sight above the critical temperature of liquid $N_2$.

• 한국분말재료학회지
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• 제25권5호
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• pp.426-434
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• 2018

In this study, $MgO-CaO-Al_2O_3-SiO_2$ (MCAS) nanocomposite glass powder having a mean particle size of 50 nm and a specific surface area of $40m^2/g$ is used as a sintering additive for AlN ceramics. Densification behaviors and thermal properties of AlN with 5 wt% MCAS nano-glass additive are investigated. Dilatometric analysis and isothermal sintering of AlN-5wt% MCAS compact demonstrates that the shrinkage of the AlN specimen increases significantly above $1,300^{\circ}C$ via liquid phase sintering of MCAS additive, and complete densification could be achieved after sintering at $1,600^{\circ}C$, which is a reduction in sintering temperature by $200^{\circ}C$ compared to conventional $AlN-Y_2O_3$ systems. The MCAS glass phase is satisfactorily distributed between AlN particles after sintering at $1,600^{\circ}C$, existing as an amorphous secondary phase. The AlN specimen attained a thermal conductivity of $82.6W/m{\cdot}K$ at $1,600^{\circ}C$.

• 한국재료학회지
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• 제31권5호
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• pp.296-300
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• 2021

Al-Cr-Si ternary quench ribbons are fabricated using a single roll method and investigated for their structural and thermal properties. In particular, the sinterability is examined by pulse current sintering to obtain the following results. The Al₇₄Cr₂₀Si₆ composition becomes a quasicrystalline single phase; by reducing the amount of Cr, it becomes a two-phase mixed structure of Al phase and quasicrystalline phase. As a result of sintering of Al₇₄Cr₂₀Si₆, Al₇₇Cr₁₃Si₁₀ and Al₉₀Cr₆Si₄ compositions, the sintering density is increased with the large amount of Al phase; the sintering density is the highest in Al₉₀Cr₆Si₄ composition. In addition, as a result of investigating the effects of sintering temperature and pressurization on the sintered density of Al₉₀Cr₆Si₄, a sintered compact of 99% or more at 513 K and 500 MPa is produced. In particular, since the Al-Cr-Si ternary crystal is more thermally stable than the Al-Cr binary quaternary crystal, it is possible to increase the sintering temperature by about 100 K. Therefore, using an alloy of Al₉₀Cr₆Si₄ composition, a sintered compact having a sintered density of 99 % or more at 613 K and 250 MPa can be manufactured. It is possible to increase the sintering temperature by using the alloy system as a ternary system. As a result, it is possible to produce a sintered body with higher density than that possible using the binary system, and at half the pressure compared with the conventional Al-Cr binary system.

• 한국분말재료학회지
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• 제20권2호
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• pp.138-141
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• 2013

The microstructure evolution during sintering of the W-5 wt.%Cu nanocomposite powders was investigated for the purpose of developing a high density W-Cu alloy. The W-5 wt.%Cu nanopowder compact, fully-densified during sintering at 1623 K, revealed a homogeneous microstructure that consists of high contiguity structures of W-W grains and an interconnected Cu phase located along the edges of the W grains. The Vickers hardness of the sintered W-5 wt.%Cu specimen was $427{\pm}22$ Hv much higher than that ($276{\pm}19$ Hv) of the conventional heavy alloy. This result is mostly due to the higher contiguity microstructure of the W grains compared to the conventional W heavy alloy.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.144-145
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• 2006

A developed molybdenum hybrid-alloyed steel powder is based on a molybdenum prealloyed steel powder to which molybdenum powder particles are diffusion bonded. The sintered compact made of this powder has a finer pore structure than that of the conventional molybdenum prealloyed steel powder, because the ferritic iron phase $({\alpha}-phase)$ with a high diffusion coefficient is formed in the sintering necks where molybdenum is concentrated resulting in enhanced sintering. The rolling contact fatigue strength of the sintered and carburized compacts made of this powder improved by a factor of 3.6 compared with that of the conventional powder due to the fine pore structures.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2017년도 추계학술논문요약집
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• pp.209-210
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• 2017

• 마이크로전자및패키징학회지
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• 제11권4호
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• pp.37-41
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• 2004

이동 통신 기기의 광대역화에 따라 기존의 인쇄 회로 기판에 비해 양호한 전기적 특성과 수동형 부품을 내장할 수 있는 LTCC(Low Temperature Co-fired Ceramic)에 대한 많은 연구 개발이 진행되고 있으나 불 균일한 수축으로 인해 적용에 한계를 보여 왔다. 본 연구에서는 짧은 시간내에 온도를 균일하게 올릴 수 있는 혼합 가열 방식을 개발하여 하부에서부터 시편의 얇은 층이 순차적으로 소결 되도록 하는 일 방향 소결의 조건을 제공하여 시편 상부 표면의 배선 형상이 종래의 전기로 가열보다 안정적으로 형성되는 결과를 얻었다. 기판의 소결 특성, 배선의 전기적 특성, 그리고 배선의 기계적 특성 등을 비교한 결과, 기판의 소형화와 배선의 고밀도화에 전기로 가열 보다 혼합 가열이 적용 가능성이 높음을 알 수 있었다.

• 마이크로전자및패키징학회지
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• 제30권1호
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• pp.1-16
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• 2023

전기차용 전력변환모듈의 성능향상 요구와 종래의 Si 전력반도체의 한계 극복을 위해 차세대 전력반도체인 wide-bandgap (WBG) 기반 전력반도체로의 전환이 가속화되고 있다. WBG 전력반도체로의 전환을 위해 전력변환모듈 패키징 소재 역시 높은 고온 내구성을 요구받고 있다. 전력변환모듈 패키징 공정 중 하나인 Ag 소결 다이접합 기술은 종래의 고온용 Pb 솔더링의 대체 기술로 주목받고 있다. 본 논문에서는 Ag 소결 다이접합 기술 관련 최신 연구동향에 대해 소개하고자 한다. 소결 다이접합 공정 조건에 따른 접합부 특성을 비교하고 Ag 소결층의 3차원 이미지 구현에 따른 다공성 Ag 소결 접합부의 물성 측정 방법론에 대해 고찰하였다. 또한 열충격 및 파워사이클 신뢰성 평가 연구동향을 분석하였다.

• 한국전기전자재료학회논문지
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• 제24권7호
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• pp.543-546
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• 2011

We studied sintering temperature to enhance the piezoelectric properties of $0.98(Na_{0.5}K_{0.5})NbO_3-0.02Li(Sb_{0.17}Ta_{0.83})O_3$+0.01wt%ZnO (hereafter NKN-LST+ZnO) lead free piezoelectric ceramics. The synthesis and sintering method were the conventional solid state reaction method and sintering was executed at $1,080\sim1,120^{\circ}C$. We found that NKN-LST+ZnO ceramics at optimal sintering temperature showed the improved piezoelectric properties at the optimal sintering temperature. The NKN-LST+ZnO ceramics show good performance with piezoelectric constant $d_{33}$= 153 pC/N sintered at $1,090^{\circ}C$. The results reveal that NKN-LST+ZnO ceramics are promising candidate materials for lead-free piezoelectric application.

• 한국결정성장학회지
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• 제17권3호
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• pp.128-132
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• 2007

방전플라즈마 소결법을 적용하여 탄화붕소 세라믹스를 제조하여 그 소결 특성, 미세 구조 및 기계적 특성을 평가하였다. 탄화붕소의 소결에 방전플라즈마 소결법을 적용하여 소결 조제의 첨가 없이 전통적인 소결법보다 낮은 온도에서 99% 이상의 완전 치밀화된 소결체를 제작할 수 있었으며, 탄화붕소 분말의 메탄을 세척을 통하여 분말 표면에 형성되어 있는 $B_2O_3$ 상을 사전에 제거함으로써 결정립의 조대화를 방지하여 균일한 미세구조의 형성을 유도할 수 있었으며 결과적으로 탄화붕소 소결체의 기계적 특성을 향상시킬 수 있었다. 특히 파괴인성의 경우 메탄을 세척을 통하여 30% 이상의 물성 향상을 달성하였다.