• Korean Journal of Materials Research
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• v.7 no.2
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• pp.145-151
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• 1997

Remelting of $A-Si/SiC_{p}$ composites followed by isothermal holding and solidification, leads ro the settling of Sic particles to the bottom of the mold. With the isothermal holding time for molten $A-Si/SiC_{p}$ composites. the particle free zone increases rapidly up to approximately first 30 minutes of the holding time. Experimental resulls of the particle settling confirm that the larger SIC particles sink faster tlun the sniiller particles. An increase in volume fraction of Sic particles decreases the setrling velocity of the particles.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.376-380
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• 2003

The microstructure and the mechanical properties of RS-SiC and RS-$SiC_f/SiC$ materials have been investigated in conjunction with the content of residual silicon and porosity. The mechanical properties of RS-SiC materials suffered from the thermal exposure were also examined. RS-SiC based materials bave been fabricated using the complex matrix slurry with different composition ratios of SiC and C panicles. The characterization of RS-SiC based materials was investigated by means of SEM, EDS ~d three point bending test. Based on the mechanical property-microstructure correlation, the high temperature applicability of RS-SiC based materials was discussed.

• Journal of the Korean Ceramic Society
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• v.37 no.9
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• pp.864-870
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• 2000

알루미나 단미의 기계적 성질을 향상시키고자, 185$0^{\circ}C$에서 1시간 동안 열간 가압소결에 의하여 SiC 입자 및 SiC 휘스커를 단독으로 혹은 동시에 첨가한 알루미나 복합재료를 제조하여 기계적 성질과 미세조직을 조사하였다. 20vol%의 SiC 입자 혹은 휘스커 첨가에 의하여, 알루미나 복합재료의 강도는 단미의 360 MPa에서 각각 640 MPa, 650 Mpa로 향상되었다. 20vol%의 SiC 입자 혹은 휘스커를 첨가한 복합재료의 파괴인성은 각각 3.5 MPa.m$^{1}$2/, 5.5 MPa.m$^{1}$2/를 나타내었다. 20vol%의 SiC 휘스커와 2vol%의 SiC 입자를 동시 첨가한 다중강화 복합재료의 강도와 파괴인성은 각각 790 MPa, 5.0 MPa.m$^{1}$2/ 로 증가하였다. 이와 같이 알루미나 단미에 비해 강도 및 파괴인성이 향상된 것은 입자에 의한 결정립 미세화 효과와 휘스커에 의한 균열편향, pull-out의 영향으로 생각된다.

• Journal of Adhesion and Interface
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• v.14 no.2
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• pp.75-81
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• 2013

Epoxy matrix based composites were fabricated by adding SiC nano fillers. The interfacial properties of composites were varied with different shapes of SiC nano fillers. To investigate the shape effects on the interfacial properties, beta and whisker type SiC nano fillers were used for this evaluation. The dispersion states of nano SiC-epoxy nanocomposites were evaluated by capacitance measurements. FE-SEM was used to observe the fracture surface of different structures of SiC-epoxy nanocomposites and to investigate for reinforcement effect. Interfacial properties between carbon fiber and SiC-epoxy nanocomposites were also evaluated by ILSS (interlaminar shear strength) and IFSS (interfacial shear strength) tests. The interfacial adhesion of beta type nanocomposites was better than whisker type.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.27-31
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• 2001

Hi-Nicalon SiC fiber reinforced SiC composites (SiC/SiC) have been fabricated by the reaction sintering process. Braided Hi-Nicalon SiC fiber with double interphases of BN and SiC was used in this composite system. The microstructures and the mechanical properties of reaction sintered SiC/SiC composites were investigated through means of electron microscopies (SEM, TEM, EDS) and bending tests. The matrix morphology of reaction sintered SiC/SiC composites was composed of the SiC phases that the composition of the silicon and the carbon is different. The TEM analysis showed that the residual silicon and the unreacted carbon were finely distributed in the matrix region of reaction sintered SiC/SiC composites. Reaction sintered SiC/SiC composites also represented proper flexural strength and fracture energy, accompanying the noncatastrophic failure behavior.

• Composites Research
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• v.22 no.3
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• pp.74-81
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• 2009

Reversed plane bending fatigue tests were conducted on SiC particle reinforced and SiC whisker reinforced aluminum composite. The initiation and growth behaviors of small surface fatigue cracks were continuously monitored by the replica technique and the causes of fracture and fracture mechanism were investigated by SEM. The relationship between da/dn and $K_{max}$ show that da/dn increases in high stress level while decrease and again increases with increasing of $K_{max}$ in low stress level for two materials.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.433-438
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• 2009

The main objective of this research effort is to develop the performance of C/SiC composites manufactured by LSI (Liquid Silicon Infiltration) method for solid and liquid rocket propulsion system and ensure the performance analysis technique. The high performance and reliability of C/SiC composite are proved for solid and liquid rocket propulsion system. And the performance analysis technique related to mathematical ablation model is originated.

• Composites Research
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• v.29 no.4
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• pp.223-229
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• 2016

SiC nanoparticles were used to increase flexural properties of polymer matrix. This study was to manufacture huge concentration SiC nanoparticle/epoxy composites and to evaluate the dispersion. During mixing SiC nanoparticle and epoxy, 20 wt% SiC nanoparticle in total composites was used with both stirrer and sonication equipment together. Mixing speed and dispersion were improved with the method by using both stirrer and sonication equipment at the same time via mechanical test and FE-SEM. Based on the results, modeling of SiC nanoparticle dispersion could be established. Ultimately, unidirectional carbon fiber reinforced composites was manufactured using 20 wt% SiC nanoparticle/epoxy. Mechanical property of CFRP using dual stirrer and sonication mixing method was better than composites by single sonication mixing method.

• Korean Journal of Materials Research
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• v.2 no.6
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• pp.461-467
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• 1992

A fabrication process for SiC whisker preform reinforced AC4A Al composites is being developed. The Al alloy used as the matrix in this study is AC4A. SiC whisker preform made by Tokai Carbon Co. Ltd. Shizuoka, Japan were used. These consisted of $\beta$-type single crystals 0.1 ~ 10${\mu}$m in diameter and 20~10${\mu}$m in length. The most adequate fabrication condition was that whisker preform was preheated up to 750~80$0^{\circ}C$, set into a mould preheated to ~40$0^{\circ}C$, molten Al alloy heated to ~80$0^{\circ}C$ and applied pressure 75MPa. And Si$C_w$reinforced AC4A composite was advanced above twice than AC4AI/M. Also it was not large effect by pressure at Si$C_w$ 20v/o.

• Journal of the Korean Ceramic Society
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• v.38 no.1
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• pp.22-27
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• 2001

$\beta$-Si$_3$N$_4$종자입자 첨가가 소결조제로 Y-Mg-Si-Al-O-N계 oxynitride glass를 사용하여 일축가압 소결을 행한 SiC-Si$_3$N$_4$복합재료의 미세구조와 기계적 특성에 미치는 영향을 고찰하였다. 길게 자란 $\beta$-Si$_3$N$_4$입자들과 등방성의 $\beta$-SiC 입자들이 균일하게 분포된 미세구조를 얻었다. $\beta$-Si$_3$N$_4$종자입자 함량이 증가함에 따라 SiC-Si$_3$N$_4$복합재료의 강도와 파괴인성이 증가하였고, 이는 복합화에 기인하는 결함크기의 감소와 길게 자란 $\beta$-Si$_3$N$_4$입자에 의한 균열가교 및 균열회절 등에 기인하였다. SiC-70 wt% Si$_3$N$_4$복합재료의 대표적인 강도와 파괴인성은 각각 770 MPa과 6.2 MPa.m$^{1}$2/ 이었다.