• Title/Summary/Keyword: $C_f/SiC$ Composite

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Densification Mechanism of NITE-SiC and $SiC_f/SiC$ Composites

  • Yoon, Han-Ki;Lee, Young-Ju;Park, Yi-Hyun;Park, Jun-Soo;Kohyama, A.
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2006.11a
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    • pp.181-184
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    • 2006
  • Nano Infiltration Transient Eutectic Phase - Silicon Carbide (NITE-SiC) and $SiC_f/SiC$ composite have been fabricated by a Hot Pressing (HP) process, using SiC powder with an average size of about 30nm. Alumina ($Al_2O_3$) and Yttria ($Y_2O_3$) were used for additives materials. These mixed powders were sintered at the temperature a of $1300^{\circ}C$, $1650^{\circ}C$, $1800^{\circ}C$ and $1900^{\circ}C$ under an applied pressure of 20MPa. And unidirection and two dimension woven structures of $SiC_f/SiC$ composites were prepared starting from Tyranno SA fiber. Densification of microstructure gives an effect to density. Specially, Densification Mechanism basically is important from the sintering which use the HP. In this study, the densification of NITE-SiC and $SiC_f/SiC$ composite mechanism by a press displacement appears investigated. The mechanism on the densification of each sintering temperature was investigated. The each step is shows a with each other different mechanism quality.

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Analysis of Thermal Shock Behavior of Cladding with SiCf/SiC Composite Protective Films (SiCf/SiC 복합체 보호막 금속피복관의 열충격 거동 분석)

  • Lee, Dong-Hee;Kim, Weon-Ju;Park, Ji-Yeon;Kim, Dae-Jong;Lee, Hyeon-Geon;Park, Kwang-Heon
    • Composites Research
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    • v.29 no.1
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    • pp.40-44
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    • 2016
  • Nuclear fuel cladding used in a nuclear power plant must possess superior oxidation resistance in the coolant atmosphere of high temperature/high pressure. However, as was the case for the critical LOCA (loss-of-coolant accident) accident that took place in the Fukushima disaster, there is a risk of hydrogen explosion when the nuclear fuel cladding and steam reacts dramatically to cause a rapid high-temperature oxidation accompanied by generation of a huge amount of hydrogen. Hence, an active search is ongoing for an alternative material to be used for manufacturing of nuclear fuel cladding. Studies are currently aimed at improving the safety of this cladding. In particular, ceramic-based nuclear fuel cladding, such as SiC, is receiving much attention due to the excellent radiation resistance, high strength, chemical durability against oxidation and corrosion, and excellent thermal conduction of ceramics. In the present study, cladding with $SiC_f/SiC$ protective films was fabricated using a process that forms a matrix phase by polymer impregnation of polycarbosilane (PCS) after filament-winding the SiC fiber onto an existing Zry-4 cladding tube. It is analyzed the oxidation and microstructure of the metal cladding with $SiC_f/SiC$ composite protective films using a drop tube furnace for thermal shock test.

Influence of Winding Patterns and Infiltration Parameters on Chemical Vapor Infiltration Behaviors of SiCf/SiC Composites (SiCf/SiC 복합체의 화학기상침착 거동에 미치는 권선 구조와 침착 변수의 영향)

  • Kim, Daejong;Ko, Myoungjin;Lee, Hyeon-Geun;Park, Ji Yeon;Kim, Weon-Ju
    • Journal of the Korean Ceramic Society
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    • v.51 no.5
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    • pp.453-458
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    • 2014
  • SiC and its composites have been considered for use as nuclear fuel cladding materials of pressurized light water reactors. In this study, a $SiC_f$/SiC composite as a constituent layer of SiC triplex fuel cladding was fabricated using a chemical vapor infiltration (CVI) process in which tubular SiC fiber preforms were prepared using a filament winding method. To enhance the matrix density of the composite layer, winding patterns, deposition temperature, and gas input ratio were controlled. Fiber arrangement and porosity were the main parameters influencing densification behaviors. Final density of the composites decreased as the SiC fiber volume fraction increased. The CVI process was optimized to densify the tubular preforms with high fiber volume fraction at a high $H_2$/MTS ratio of 20 at $1000^{\circ}C$; in this process, surface canning of the composites was effectively retarded.

Fabrication of SiCf/SiC Composite by Chemical Vapor Infiltration (화학기상침착법에 의한 SiCf/SiC 복합체의 제조)

  • Park, Ji Yeon;Kim, Daejong;Kim, Weon-Ju
    • Composites Research
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    • v.30 no.2
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    • pp.108-115
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    • 2017
  • Among several fabrication processes of $SiC_f/SiC$ composites, the chemical vapor infiltration (CVI) process has attractive advantages in manufacturing complex net-or near-net-shape components at relatively low temperatures, easily controlling the microstructure of the matrix and obtaining the highest SiC purity level. However, it has disadvantages in that the ratio of residual pores in matrix is higher than other processes and processing time is relatively long. To reduce the residual porosity, the whisker-growing-assisted CVI process, which is composed of whisker growth and matrix filling steps has been developed. The whiskers grown before matrix filling may serve to divide the large natural pores between the fibers or bundles so that the matrix can be effectively filled into the finely divided pores. In this paper, the fundamentals of the CVI process for preparation of $SiC_f/SiC$ composites and some experimental results prepared by CVI and whisker-growing-assisted CVI processes are briefly introduced.

CHARACTERIZATION OF MONOLITHIC RS-SiC AND RS-$SiC_f/SiC$ COMPOSITE MATERIALS (반응소결 SiC 재료와 $SiC_f/SiC$ 복합재료의 특성)

  • Jin, Joon-Ok;Lee, Sang-Pill;Lee, Jin-Kyung;Yoon, Han-Ki;Khoyama, Akira
    • 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.

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Effect of SiC Nanorods on Mechanical and Thermal Properties of SiC Composites Fabricated by Chemical Vapor Infiltration

  • Lee, Ho Wook;Kim, Daejong;Lee, Hyeon-Geun;Kim, Weon-Ju;Yoon, Soon Gil;Park, Ji Yeon
    • Journal of the Korean Ceramic Society
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    • v.56 no.5
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    • pp.453-460
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    • 2019
  • To reduce residual pores of composites and obtain a dense matrix, SiCf/SiC composites were fabricated by chemical vapor deposition (CVI) using SiC nanorods. SiC nanorods were uniformly grown in the thickness direction of the composite preform when the reaction pressure was maintained at 50 torr or 100 torr at 1,100℃. When SiC nanorods were grown, the densities of the composites were 2.57 ~ 2.65 g/㎤, higher than that of the composite density of 2.47 g/㎤ for non-growing of SiC nanorods under the same conditions; grown nanorods had uniform microstructure with reduced large pores between bundles. The flexural strength, fracture toughness and thermal conductivity (room temperature) of the SiC nanorod grown composites were 412 ~ 432 MPa, 13.79 ~ 14.94 MPa·m1/2 and 11.51 ~11.89 W/m·K, which were increases of 30%, 25%, and 25% compared to the untreated composite, respectively.

Fracture Behaviors of SiCf/SiC Composites Prepared by Hybrid Processes of CVI and PIP (화학침착법과 고분자함침 열분해법의 복합공정으로 제조한 SiCf/SiC 복합체의 제조 공정에 따른 파괴거동)

  • Park, Ji Yeon;Han, Jangwon;Kim, Daejong;Kim, Weon-Ju;Lee, Sea Hoon
    • Journal of the Korean Ceramic Society
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    • v.51 no.5
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    • pp.430-434
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    • 2014
  • $SiC_f$/SiC composites were prepared using the hybrid process of chemical vapor infiltration (CVI) and polymer impregnation and pyrolysis (PIP). Before the application of PIP, partially matrix-filled preform composites with different densities were fabricated by control of chemical vapor infiltration time and temperature. The changes of the final density of the $SiC_f$/SiC composites had a tendency similar to that of preform composites partially filled by CVI. Composites with lower density after the CVI process had a larger increment of density during the PIP process. Three types of microstructures were observed on the fractured surface of the composite: 1) well pulled-out fibers and lower density, 2) slightly pulled-out fibers and higher density, and 3) only bulk SiC. The different fractions and distributions of the microstructures could have an effect on the mechanical properties of the composites. In this study, $SiC_f$/SiC composites prepared using a hybrid process of CVI and PIP had density values in the range of $1.05{\sim}1.44g/cm^3$, tensile strength values in the range of 76.4 ~ 130.7 MPa, and fracture toughness values in the range of $11.2{\sim}13.5MPa{\cdot}m^{1/2}$.

Fracture Properties of Carbon Coated LPS-SiCf/SiC Composites (액상소결을 이용한 탄소코팅 SiCf/SiC복합재료의 파괴특성)

  • Kim, Sung-Won;Lee, Moon-Hee;Hwang, Seung-Kuk;Lee, Sang-Pill
    • 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.

Microstructure and Strength Property of Liquid Phase Sintered $SiC_f$/SiC Composites (액상소결 $SiC_f$/SiC 복합재료의 미세조직 및 강도특성)

  • Lee, Moon-Hee;Cho, Kyung-Seo;Lee, Sang-Pill;Lee, Jin-Kyung
    • 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.

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