• 한국세라믹학회지
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• 제37권11호
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• pp.1033-1038
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• 2000

알루미나의 소결시 외부압력이 알루미나의 입자성장에 미치는 영향을 sinter-HIP을 통해 고찰하였다. 알루미나 입자는 HIP 초기에 일정하게 빠른 속도로 성장하였으나 HIP 처리시간이 30분을 경과한 이후에는 완만한 속도로 성장하였다. 상압소결된 알루미나를 HIP 처리시 입자성장 속도지수는 상압소결시와 동일한 n=3을 나타내었으나 알루미나의 입자성장속도는 HIP 처리시의 외부 압력으로 인해 감소하였다. Sinter-HIP 소결시 순수 알루미나와 M햬가 첨가된 알루미나의 경우 계산된 속도상수 k는 대략적으로 각각 9.2×10/sup -20/ ㎥/s, 2.6×10/sup -21/ ㎥/s 이었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.11-12
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• 2010

• 한국세라믹학회지
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• 제38권2호
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• pp.179-182
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• 2001

Al$_2$O$_3$-5 vol% SiC 나노복합재료의 sinter plus HIP에 의한 치밀화시 일어나는 기공의 변화에 초점을 두어 치밀화 거동을 관찰하였다. $Al_2$O$_3$-SiC 시편은 질소분위기 중의 상압소결과 이후의 열간정수압소결(HIP)에 의해 완전치밀화가 이루어졌다. 155$0^{\circ}C$의 상압소결에 의해서는 90%의 비교적 낮은 상대밀도가 얻어졌으나, 기공의 폐기공화로 이후의 열간정수압소결(HIP)에 의해 99.6%의 완전치밀화가 가능하였다. 상압소결한 시편을 X-선 회절기와 주사전자현미경(SEM)으로 관찰한 결과, 선택적으로 시편 표면부에서만 SiAl$_{6}$O$_2$N$_{6}$과 AlN 등으로 이루어진 치밀화된 반응층을 확인할 수 있었으며, 이러한 표면 반응층이 비교적 낮은 상대밀도의 시편내의 모든 기공을 폐기공화하는 효과를 주는 것을 알 수 있었다.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.627-628
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• 2006

The present work is a study on the argon gas pressure effects of Sinter/HIP sintering on microstructure and strength of different grades of TiC-NiMo cermets. Titanium carbide in the composition of different grades of TiC-NiMo cermets was ranged from 40 to 80 wt.% and the ratio of nickel to molybdenum in the initial powder composition was 1:1, 2:1 and 4:1 respectively. On the sintered alloys, the main strength characteristic, transverse rupture strength (TRS) was measured. Furthermore, the microstructure parameters of some alloys were measured and the pressure effect on pore elimination was evaluated. All the results were compared with common, vacuum sintered alloys. The TRS values of TiC-NiMo cermets could be considerably improved by using Sinter/HIP technique, for high-carbide fraction alloys and for alloys sintered at elevated temperatures.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1988년도 추계학술대회 논문집
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• pp.36-40
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• 1988

High TC Y-Ba-Cu-O Superconductors were fabricated by sintering, sinter+HIP encapsulation. Specimens were sintered at 920$^{\circ}C$∼960$^{\circ}C$. A part of sintered specimens were treated by HIP, and HIP conditions were 150 MPa, 880$^{\circ}C$, 30min under the Ar atmosphere. The relative density of HIP specimens was increased 5∼8% in comparison with sintered one(90∼93% relative density). X-ray analysis represented the orthorhobic-tetragonal phase transition with annealing condition. Tc measurements showed a sharp drp within 3$^{\circ}C$, 91K onset and 89K offset. Transport current density(Jc) of sintered specimens showed typically∼159A/㎤ but that of sinter+HIP encapsulation was decreased to∼89A/㎤ because of insufficient oxygen diffusion, Hardness(H) and Toughness(Kc) were increased to 38GPa; and 2.9 MPam$\^$$\frac{1}{2}$/, respectively.

• 한국세라믹학회지
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• 제37권7호
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• pp.617-624
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• 2000

Abnormal grain growth in alumina was investigated during sinter-HIP process for better understanding of pressure effect on microstructural development. Abnormal grain growth of monolithic alumina was observed near surface region rather than interior region of specimen. Finite element analysis was used to estimate the pressure distribution developed in the specimen. Pressure distribution analysis was in good agreement with grain size distributjion in the specimen. The results of finite element analysis provided that abnormal grain growth monolithic alumina was resulted from the inhomogeneous pressure distribution in the specimen. MgO addition in alumina was effective for the suppression of abnormal grain growth in alumina under inhomogeneous pressure distribution during sinter-HIP process.

• 자연과학논문집
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• 제8권1호
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• pp.53-59
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• 1995

Alumina 세라믹스의 기계적 물성 증진을 위하여 SiC whisker로 강화시키고 소결 조제 및 소결 온도의 영향을 고찰하였다. Whiker의 소결억제 효과로 인하여 고상소결을 촉진하는 MgO나 $TiO_2$를 소결조제로 사용한 경우에서는 치밀한 소결체를 얻을 수 없었으나, 액상을 형성하는 $Y_2O_3$를 2wt% 첨가한 경우에 양호한 소결밀도를 얻을 수 있었다. whisker 첨가에 의한 기지의 기계적 물성의 증진 효과도 함께 얻을 수 있었다. 강화 효과는 보강재인 whiker 자체의 보강 효과와 함께 입성장 억제 효과가 복합적으로 작용한 것으로 판단되었다. 소결체를 HIP 처리한 경우에는 거의 이론 밀도까지 이르는 아주 치밀한 소결체의 제조가 가능하였으며, 기계적 물성은 상압소결 후의 결과에 비하여 향상됨을 확인할 수 있었다.

• 한국세라믹학회지
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• 제33권6호
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• pp.709-717
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• 1996

Design parameter of Si3N4 for engineering part could be calculated through the measurement of tensile strength with cylindrical specimen($\Phi$=7.15, ι=110mm) Relative densities of Si3N4 test specimen prepared by pressure-less sintering (PLS) and sinter/HIP were 98.5 and 99.2% respectively. Tensile strength of Si3N4 was 378 MPa for PLS and 509 MPa for sinter/HIP. By the Weibull statistic Design parameter such as Weibull modulus m=8-12 could be calcuated. Fracture strength of Si3N4 related to volume could be effectively pridicted by using Weibull theory.

• 한국세라믹학회지
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• 제32권7호
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• pp.846-852
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• 1995

The multiply reinforced mullite-zirconia composites were prepared with addition of Al2O3 particles, platelets, and fibers. The sinter-HIP specimens (presintered at 1$700^{\circ}C$ and hipped at 1$600^{\circ}C$) showed that the fracture toughness of Al2O3 fiber reinforcement (4.4 MPa.{{{{ SQRT {m} }}) was higher than those of platelet (4.0 MPa.{{{{ SQRT {m} }}) and of particle (3.9MPa.{{{{ SQRT {m} }}) reinforcement, whereas the fracture strength of Al2O3 particle reinforcement (304 MPa) was higher than those of platelet (293MPa) and of fiber (248MPa) reinforcement.

• 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.