• 한국재료학회지
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• 제16권6호
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• pp.341-345
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• 2006

[ $Ni_2Si$ ] mixed powders were mechanically alloyed by a ball mill and then processed by hot isostatic pressing (HIP) and spark plasma sintering (SPS). In the powder that was mechanically alloyed for 15minutes(MA 15 min), only Ni and Si were observed but in the powder that was mechanically alloyed for 30minutes(MA 30 min), $Ni_2Si$, Ni and Si were mixed together. Some of the MA 15 min powder and MA 30 min powder were processed by HIP under pressure of 150MPa at the temperature of $1000^{\circ}C$ for two hours and some of them were processed by SPS under pressure of 60 MPa at the temperature of $1000^{\circ}C$ for 60 seconds. Both methods completely compounded the powders to $Ni_2Si$. The maximum density of sintered lumps by HIP method was 99.5% and the maximum density of the sintered lump by SPS method was 99.3%. with the hardness of HRc 66 with the hardness of HRc 63. Therefore, the SPS method that can sinter in short time at low cost is considered to be more economical that the HIP method that requires complicated sintering conditions and high cost and the sintering can produce target materials in desired sizes and shapes to be used for thin film.

• 한국분말재료학회지
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• 제16권5호
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• pp.326-335
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• 2009

Fe based (Fe$_{68.2}$C$_{5.9}$Si$_{3.5}$B$_{6.7}$P$_{9.6}$Cr$_{2.1}$Mo$_{2.0}$Al$_{2.0}$) amorphous powder, which is a composition of iron blast cast slag, were produced by a gas atomization process, and sequently mixed with ductile Cu powder by a mechanical ball milling process. The Fe-based amorphous powders and the Fe-Cu composite powders were compacted by a spark plasma sintering (SPS) process. Densification of the Fe amorphous-Cu composited powders by spark plasma sintering of was occurred through a plastic deformation of the each amorphous powder and Cu phase. The SPS samples milled by AGO-2 under 500 rpm had the best homogeneity of Cu phase and showed the smallest Cu pool size. Micro-Vickers hardness of the as-SPSed specimens was changed with the milling processes.

• 한국결정성장학회지
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• 제12권4호
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• pp.172-177
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• 2002

CuZnAl계 형상기억합금은 경제성, 열간 가공성 등이 우수하며 변태온도의 조절이 쉬운 등 여러 장점을 가지고 있으나, 열간 가공 중에 결정립이 쉽게 커지며, 취성이 심하고, 열이력에 대해서 형상기억 효과가 빨리 감소되는 등의 단점이 있다. 이러한 단점들은 결정립크기를 미세화함으로써 어느 정도 해소할 수 있다고 알려져 있다. 본 연구에서는 Cu-24.78Zn-9.11Al(at.%)과 Cu-13.22Zn-17.24Al(at.%)의 조성을 갖으며 비교적 작은 결정립크기를 갖는 형상기억합금을 99.9% 이상의 순도를 갖는 Cu, Zn 및 Al원소분말을 이용하여 SPS(spark plasma sintering) 방법으로 제조하였다. SPS 공정을 통하여 원소분말을 이용한 합금화가 가능함을 확인하였으며, 75-150 $\mu \textrm{m}$ 크기의 원소분말을 이용하여 제조한 경우, 두 조성 모두에서 약 70$\mu$m 의 결정립크기를 얻을 수 있었으며, 조성에 따라 상온에서 오스테나이트 단상 혹은 마르텐사이트 단상을 나타냄을 확인하였다.

• 한국결정성장학회지
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• 제15권2호
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• pp.75-78
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• 2005

본 연구에서는 고온 융점과 높은 Seebeck 계수로 인해 고온 열전 재료로서 매우 우수한 silicon boride ($SiB_6$)의 고밀도 소결체를 방전 플라즈마 소결법(spark plasma sintering, SPS)을 도입하여 제조하였으며, 소결된 시편의 미세구조 및 열전 특성을 평가하였다. $1500^{\circ}C$의 비교적 저온에서 이론 밀도의 약 99%의 소결밀도로 SPS법을 통해 효과적으로 $SiB_6$를 치밀화 할 수 있었으며 이들 시편들의 열전특성 평가로부터, hot-press법으로 제조된 시편과 비교하여 매우 향상된 Seebeck 계수를 얻을 수 있었으며 상대적으로 높은 출력인자 값을 나타냈다.

• 한국분말재료학회지
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• 제9권1호
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• pp.50-60
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• 2002

SPS(Spark Plasma Sintering ) is known to be an excellent sintering method for porous materials. In the present work an attempt has been made of fabricating porous 316L Stainless steel with good mechanical properties by using controlled SPS process Porosity was 21%~53% at sintering temperature of $600^{\circ}C$~100$0^{\circ}C$ The limit of porosity with available mechanical strength was 30% at given experimental conditions. Porosity can be controlled by manipulating the intial height of the compact by means of the supporter and punch length. The applied pressure can be exerted entirely upon the supporter, giving no influence on the specimen. The specimen is then able to be sintered pressurelessly. In this case porosity could be controlled from 38 to 45% with good mechanical strength at sintering temperature of 90$0^{\circ}C$. As the holding time increased, neck between the particles grew progressively, but shrinkage of the specimen did not occur, implying that the porosity remained constant during the whole sintering process.

• 세라미스트
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• 제22권2호
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• pp.170-181
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• 2019

All-solid-state batteries have received increasing attention because of their high safety aspect and high energy and power densities. However, the inferior solid-solid interfaces between solid electrolyte and active materials in electrode, which cause high interfacial resistance, reduce ion and electron transfer rate and limit battery performance. Recently, spark plasma sintering is emerging as a promising technique for fabricating solid electrolytes and composite-electrodes. Herein, this paper focuses on the overview of spark plasma sintering to fabricate solid electrolytes and composite-electrodes for all-solid-state batteries. In the end, future opportunities and challenges associated with SPS technique for all-solid-state batteries are described.

• 한국결정성장학회지
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• 제12권3호
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• pp.144-148
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• 2002

수산화아파타이트/티타늄 복합체를 스파크 플라즈마 소결(SPS) 장치를 이용하여 4층 경사 기능 재료 (FGM)로 제조하였다. 수산화아파타이트/티타늄 복합체의 최대 밀도와 이축 강도는 $1200^{\circ}C$에서 8분 동안의 SPS 조건에서 얻었다. 그러나, 수산화아파타이트는 $1100^{\circ}C$에서 사칼슘인산염(TetCP)으로 분해되었고, 티탄산칼숨 화합물 ($CaTiO_3$)이 형성되었다. 수산화아파타이트에 티타늄을 첨가하면 수산화아파타이트가 저온에서 쉽게 분해되었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1442-1443
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• 2006

본 논문에서는 분말 연자성체에 플라즈마를 이용하였을 때 특성 개선에 관한 연구이다. 기존의 압분 방식은 낮은 강도를 갖는 단점 때문에 신뢰성에 문제가 있어서, 직접적인 모터분야에 연자성체(SMC)를 적용하는데 큰 문제점 이였다. 그러나 본 논문에서 제안하는 SPS(Spark Plasma sintering)공법을 적용한 모터 코어 제조 방법은 플라즈마를 이용하여 분말의 표면에서만 접촉이 일어나게 하는 소결 방식으로, 내부재질의 특성변화 없이 표면의 절연층끼리만 접촉되게 하여 자기적 특성의 손상없이 기계적인 강도를 높일 수 있었다. 실제적으로 기존의 압분체(Hoganass550+윤활제(KE))의 경우 파단강도가 700Mpa정도였으나 SPS를 적용시 1200Mpa까지 증가 되었다. 이러한 SPS 공법을 통해 연자성체(SMC)재질의 모터 Core 분야 적용하는 데 생기는 문제점을 해결하고자 하였다.

• 열처리공학회지
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• 제33권4호
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• pp.185-192
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• 2020

In this study, materials characterization of pure copper and copper based carbon nano-tube composite prepared by powder metallurgy method were investigated. Prior to evaluate materials characterization, spark plasma sintering processing variables such as sintering temperature, pressure, thickness and diameter of compacts was optimized to ensure the microstructure and materials property of pure Cu and Cu-CNT composite. In addition, corrosion behavior of Cu-based CNT composite produced by powder sintering method was investigated. It was confirmed from this study that the corroded surfaces of the composite shows less dissolution compared with pure copper in 3.5 wt% NaCl solution. The measured corrosion current density (I_corr) indicates improved corrosion property of Cu based composite containing small additions of CNTs in chloride containing media. Micro-galvanic activity between Cu and CNT was not observed in given sintering condition.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.529-530
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• 2006

This paper concerned with SPS (spark plasma sintering), hot pressing of sinter nanometer WC-Co powder and discussed the density, hardness, microstructures and grain sizes of the alloys sintered. The results showed that the two sintered techniques could produce high density alloys and play well on the grain growth, but SPS could lower the sintering temperature and shorten sintering time. Besides, the hardness of the sintered cemented alloys that was dependent on the grain size and densification could also be improved.