• Composites Research
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• v.32 no.3
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• pp.148-157
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• 2019

In this study, $C_f/SiC$, $SiC_f/SiC$ and $C_f-SiC_f/SiC$ ceramic composites reinforcing carbon fiber, SiC fiber and hybrid fiber were fabricated by hybrid TGCVI and PIP process. After the thermal shock cycle, 3-point bending and Oxy-Acetylene torch test, their mechanical behavior, oxidation and erosion resistance were evaluated. The $C_f/SiC$ composite showed a decrease in mechanical property along with increasing temperature, a pseudo-ductile fracture mode and a large quantity of erosion. The $SiC_f/SiC$ composite exhibited stronger mechanical property and lower erosion rate compared to the $C_f/SiC$, but brittle fracture mode. On the other hand, hybrid type of $C_f-SiC_f/SiC$ composite gave the best mechanical property, more ductile failure mode than the $SiC_f/SiC$, and lower erosion rate than the $C_f/SiC$. During the Oxy-Acetylene torch test, the $SiO_2$ formed by reaction of the SiC matrix with oxygen prevented further oxidation or erosion of the fibers for $C_f-SiC_f/SiC$ and $SiC_f/SiC$ composites particularly. In conclusion, if a hybrid composite with low porosity is prepared, this material is expected to have high applicability as a high temperature thermo-structural composite under high temperature oxidation atmosphere by improving low mechanical property due to the oxidation of $C_f/SiC$ and brittle fracture mode of $SiC_f/SiC$ composite.

• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.1
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• pp.23-30
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• 2014

The wear characteristics of $SiC_f$/SiC composites were evaluated according to the alignment direction of the fibers, and the elastic wave-generated friction was detected and analyzed in wearing. The friction coefficient and wear loss were similar in the longitudinal and the transverse direction of the fibers. However, these values were lower in the vertical direction of the fibers because of the brittle nature of the fiber. The friction coefficient and the wear loss were directly proportional to each other. The dominant frequencies were 58.6 kHz for monolithic SiC and 117.2 and 136.7 kHz for $SiC_f$/SiC composites, respectively.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.102-105
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• 2005

The mechanical properties of $SiC_f/SiC$ composites reinforced with continuous SiC fiber have been investigated in conjunction with the detailed analysis of their microstructures. Especially, the effect of test temperature on the characterization of $SiC_f/SiC$ composites was examined. In this composite system, a braiding Hi-Nicalon SiC fibric was selected as a reinforcement. $SiC_f/SiC$ composites have been fabricated by the reaction sintering process, using the complex matrix slurry with a constant composition ratio of SiC and C particles. The characterization of $RS-SiC_f/SiC$ composites was investigated by means of SEM, EDS and three point bending test. Based on the mechanical property-microstructure correlation, the high temperature applicability of $RS-SiC_f/SiC$ composites was discussed.

• Journal of the Korean Ceramic Society
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• v.48 no.5
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• pp.335-341
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• 2011

Continuous SiC fiber-reinforced SiC-matrix composites ($SiC_f$/SiC) had been fabricated by electrophoretic infiltration combined with ultrasonication. Nano-sized ${\beta}$-SiC added with 12 wt% of $Al_2O_3-Y_2O_3$ additive and Tyranno$^{TM}$-SA3 fabric were used as a matrix phase and fiber reinforcement, respectively. After hot pressing at 5 different conditions, the density, microstructure and mechanical properties of $SiC_f$/SiC were characterized. Hot pressing at relatively severe conditions, such as $1750^{\circ}C$ for 1 and 2 h, resulted in a brittle fracture behavior due to the strong fiber-matrix interface in spite of their high flexural strength. On the other hand, toughened $SiC_f$/SiC composite could be achieved by hot pressing at milder condition because of the formation of weak interface in spite of the decreased flexural strength. These results proposed the importance of weak fiber-matrix interface in the fabrication of ductile $SiC_f$/SiC composite.

• 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 Society of Industry Convergence
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• v.20 no.2
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• pp.149-155
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• 2017

Mechanical properties of carbon coated $SiC_f/SiC$ composites have been investigated, in conjunction with a detailed analysis of microstructure. Especially, the fracture behavior of $SiC_f/SiC$ composites by the induction of carbon coating layers has been examined. The matrix region of $SiC_f/SiC$ composites with ultra-fine SiC powders were consolidated by a liquid phase sintering (LPS) process, using a sintering additive of $Al_2O_3-Y_2O_3$ powder compound. In this composite, plain and satin- woven Tyranno SA fabrics were also utilized as a reinforcing material. A carbon interfacial layer was coated around satin-woven SiC fabrics. The characterization of LPS-$SiC_f/SiC$ composites was investigated by means of SEM and three point bending test.

• Ceramist
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• v.13 no.6
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• pp.7-12
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• 2010

극한환경용 소재기술의 발전은 새로운 기기의 설계 및 제작을 가능하게 하고, 이에 따른 고효율 시스템의 운전을 실현할 수 있게 한다. 청정 에너지 확보, 에너지 전환 효율 극대화, 항공우주 기술의 확보 등 21세기 신성장 동력산업의 주요 이슈들은 시스템 운전여건을 고온의 극한 환경으로 처하게 한다. $SiC_f$/SiC 복합체는 우수한 고온 성능으로 고온 극한환경에 적용할 수 있는 잠재성을 지닌 소재로 항공우주 산업, 방위산업, 원자력 산업 및 에너지 산업에서 적용되고 있거나 적용이 검토되고 있다. 일본은 OASIS (Organization of Advanced Sustainability Initiative for Energy System/Material) 주도로 FEEMA 프로젝트에서 엔진부품용 $SiC_f$/SiC 복합체 개발을 추진 중이며, 유럽연합과 BA (Broad Approach) 프로젝트를 통하여 핵융합로 적용소재에 관한 연구를 수행 중이다. 또한 미국과 TITAN 공동프로젝트 내에서도 $SiC_f$/SiC 복합체에 대한 연구가 진행 중이다. 미국의 일본과의 TITAN외에도 일본원자력연구원 (JAEA) 및 프랑스 원자력연구소 (CEA)와도 공동연구를 수행하고 있다. 프랑스 CEA는 고온가스로의 피복재로 개발을 수행하고 있다. 이외에도 유럽연합은 RAPHAEL 프로그램과EXTREMAT 프로그램에서 $SiC_f$/SiC 복합체 개발을 수행하고 있다. 또한 소규모이지만 $SiC_f$/SiC 복합체의 상업적인 판매가 일본에서 시작되었고, 가까운 미래에 범용적으로 적용할 상업적인 판매를 시작하는 단계로 발전할 수 있으리라 생각된다. 이외에도 미국 ASME는 고온 설계코드 개발을 위한 준비를 진행 중이다. 아울러 가속화된 제조공정 기술 개발과 설계코드 및 DB 구축과 같은 소재 적용여건의 성숙은 $SiC_f$/SiC 복합체가 상용소재로 적용될 가능성을 높이고 있으며, 개량 후보소재에서 현용재로 적용될 시기를 앞당길 수 있는 계기가 되리라 생각된다. 따라서 국내에서 이에 걸맞는 체계적인 투자와 연구가 진행되어야하겠다.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.234-238
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• 2008

The efficiency of fiber reinforced CMC(ceramic matrix composite) on the SiC materials have been investigated, in conjunction with the fabrication process by liquid phase sintering and the characterization. LPS-$SiC_f$/SiC composites was studied with the detailed analysis such as the microstructure, sintered density, flexural strength and fracture behavior. The applicability of carbon interfacial layer has been also investigated in the LPS process. Submicron SiC powder with the constant total amount and composition ratio of $Al_2O_3,\;Y_2O_3$ as sintering additives was used in order to promote the performance of the SiC matrix material. LPS-$SiC_f$/SiC composites were fabricated with hot press under the sintering temperature and applied pressure of $1820^{\circ}C$ and 20MPa for 1hr. The typical property of monolithic LPS-SiC materials was compared with LPS-$SiC_f$/SiC composites.

• Journal of Power System Engineering
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• v.17 no.4
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• pp.94-102
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• 2013

Manufactured $SiC_f/SiC$ composites by NITE method was investigated fracture characteristics according to the size of the surface crack. Coated surface crack with a $SiO_2$ colloid in several ways was evaluating the possibility of healing. The strength of CCS and UCS is 313 and 230MPa, respectively and it is about 1/3 of the SPS. Bending strength of $SiC_f/SiC$ composites has no effect with the pre-crack size to the critical crack size. $SiC_f/SiC$ composites can not generate large amount of $SiO_2$ oxides to the bottom of crack, and is only generated randomly on surfaces, and can not contribute to the recovery of bending strength.

• Journal of the Korean Ceramic Society
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• v.46 no.5
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• pp.484-487
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• 2009

$SiC_f$/SiC composites with whiskers and pyrolytic carbon (PyC) coated whiskers in the matrix were fabricated for enhancement of the fracture behaviors by the whisker growing assisted chemical vapor infiltration (WA-CVI) process, respectively. $SiC_f$/SiC composites were also prepared by the conventional CVI process as reference material. The mechanical properties and fracture behaviors were analyzed by comparison of the two types of composites prepared by WA-CVI and conventional CVI. The densities of $SiC_f$/SiC composites were in the range of $2.6{\sim}2.65g/cm^3$. The flexural strengths of composite with whiskers and with those coated by PyC were 650 MPa and 600 MPa, respectively. The tensile strength of composites with whiskers was ${\sim}285$ MPa.