• 한국세라믹학회지
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• 제51권5호
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• pp.459-465
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• 2014

In this study, Si-SiC composites were fabricated using a Si melt infiltration method using ${\beta}$-SiC/C composite powders synthesized by the carbothermal reduction of $SiO_2-C$ precursors made from a TEOS and a phenol resin. The purity of the synthesized SiC-C composite powders was higher than 99.9993 wt% and the average particle size varied from 4 to $6{\mu}m$ with increasing carbon contents of the $SiO_2-C$ precursors. It was found that the Si-SiC composites fabricated in this study consist of ${\beta}$-SiC and residual Si, without any trace of ${\alpha}$-SiC. The 3-point bending strengths of the fabricated Si-SiC composites were measured and found to be higher than 550 MPa, although the density of the fabricated Si-SiC composite was less than $2.9g/cm^3$. The bending strengths and the densities of the fabricated Si-SiC composites were found to decrease with increasing C/Si mole ratios in the SiC-C composite powders. The specific resistivities of the Si-SiC composites fabricated using the SiC-C composite powders were less than $0.018{\Omega}cm$. With increasing C content in the SiC-C composite powders used for the fabrication of Si-SiC composites, the specific resistivity of the Si-SiC composites was found to slightly increase from 0.0157 to $0.018{\Omega}cm$.

• 한국세라믹학회지
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• 제34권5호
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• pp.535-543
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• 1997

The surface of SiC particles were partially oxidized to produce SiO2 layers on the SiC particles to prepare Al2O3/SiC composite by formation of mullite bonds between the grains of Al2O3 and SiC during sintering at 1$600^{\circ}C$. This process is considered to enable the sintering of Al2O3/SiC composite at lower temperature and also to relieve the stress, produced by thermal expansion mismatch between Al2O3 and SiC. In fact, Al2O3/SiC composite prepared by oxidation of SiC was observed to be more effectively sintered and densified at lower temperature. Maximum density, flexural strength and microhardness were obtained with 5.65 vol% of mullite content in Al2O3/SiC composite.

• Nuclear Engineering and Technology
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• 제45권4호
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• pp.565-572
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• 2013

The fabrication methods and requirements of the fiber, interphase, and matrix of nuclear grade $SiC_f/SiC$ composites are briefly reviewed. A CVI-processed $SiC_f/SiC$ composite with a PyC or $(PyC-SiC)_n$ interphase utilizing Hi-Nicalon Type S or Tyranno SA3 fiber is currently the best combination in terms of the irradiation performance. We also describe important material issues for the application of SiC composites to LWR fuel cladding. The kinetics of the SiC corrosion under LWR conditions needs to be clarified to confirm the possibility of a burn-up extension and the cost-benefit effect of the SiC composite cladding. In addition, the development of end-plug joining technology and fission products retention capability of the ceramic composite tube would be key challenges for the successful application of SiC composite cladding.

• 한국세라믹학회지
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• 제34권4호
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• pp.406-412
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• 1997

Al2O3/SiC hybrid-composite has been fabricated by the conventional powder process. The addition of $\alpha$-Al2O3 as seed particles in the transformation of ${\gamma}$-Al2O3 to $\alpha$-Al2O3 provided a homogeneity of the microstructure. The grain growth of Al2O3 are significantly surpressed by the addition of nano-size SiC particles. Dislocation were produced due to the difference of thermal expansion coefficient between Al2O3 and SiC and piled up on SiC particles in Al2O3 matrix, resulting in transgranular fracture. The high fracture strength of the composite was contributed to the grain refinement and the transgranular fracture mode. The addition of SiC platelets to Al2O3/SiC nano-composite decreased the fracture strength, but increased the fracture toughness. Coated SiC platelets with nitrides such as BN and Si3N4 enhanced fracture toughness much more than non-coated SiC platelets by enhancing crack deflection.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.859-860
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• 2006

TiC-$TiB_2$-SiC system was a ternary eutectic, whose eutectic composition was 34TiC-$22TiB_2$-44SiC (mol%). TiC-$TiB_2$-SiC ternary eutectic composite were synthesized by a floating zone method using TiC, $TiB_2$ and SiC powders as starting materials. The TiC-$TiB_2$-SiC eutectic composite showed a lamellar texture. TiC(022), $TiB_2(010)$ and SiC(111) of the eutectic composite were perpendicular to the growth direction. TiC-$TiB_2$-SiC ternary eutectic composite had specific relationship among the crystal planes: TiC[011]//$TiB_2[010]$//SiC[112], TiC(200)//$TiB_2$(001)//SiC(402) and $TiC(1\bar{1}1)$//$TiB_2(101)$//SiC(220).

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 춘계학술발표대회 논문집
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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.

• 연구논문집
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• 통권26호
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• pp.103-112
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• 1996

$Al_2O_3/SiC$ Hybrid-Composite이 일반적인 분말공정에 의하여 제조되었다. 소결시 $\gamma-Al_2O_3에서 $\alpha-Al_2O_3$로의 전이에 seed역할을 하는 $\alpha-Al_2O_3의 첨가는 균일한 미세구조를 발달시켜 강도의 증진을 가져왔다. nano size의 SiC의 첨가는 $Al_2O_3$의 소결성과 입성장에 영향을 미쳐 파괴강도의 증진을 가져왔다. $Al_2O_3/SiC$ nano-Composite에 SiC plates의 첨가는 파괴강도의 감소를 가져왔지만, 상대적으로 파괴인성은 증진되었다. SiC plates에 nitride (BN, $Si_3N_4$ 코팅을 할 경우 crack deflection을 더욱 유발하여 파괴인성이 증진되었다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.110-114
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• 2012

We studied on the nondestructive evaluation of the elastic wave signal of SiC ceramics and SiC/SiC composite ceramics under monotonic tensile loading. The elastic wave signal of cross and unidirectional SiC/SiC composite ceramics were obtained by pencil lead method and bending test. It was applied for the time-frequency method which used by the discrete wavelet analysis algorithm. The time-frequency analysis provides time variation of each frequency component involved in a waveform, which makes it possible to evaluate the contribution of SiC fiber frequency. The results were compared with the characteristic of frequency group from SiC slurry and fiber. Based on the results, if it is possible to shift up and design as a higher frequency group, we will can make the superior material better than those of exiting SiC/SiC composites.

• 한국세라믹학회지
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• 제43권8호
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• pp.509-514
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• 2006

In this study, chopped Hi-Nicalon SiC fiber Reinforced Porous Reaction Bonded SiC (RBSC) composites and it fabrication process were developed by using Si melt infiltration process. The porosity and average pore size in fabricated chopped SiC fiber reinforced porous RBSC composites were in the range of $30{\sim}40%$ and $40-90{\mu}m$, which mainly determined by the SiC powder size used as starting material and amount of residual Si in porous composites. The maximum flexural strength of chopped SiC fiber reinforced porous RBSC composite was as high as 80 MPa. The delayed fracture behavior was observed in chopped SiC fiber reinforced porous RBSC composites upon 3-point bending strength test.

• 대한기계학회논문집
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• 제19권2호
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• pp.475-485
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• 1995

In this study, statistical analysis of fatigue data which had obtained from respective 24 fatigue crack, was examined for SiC whisker reinforced aluminium 6061 composite alloy (SiC$_{w}$/A16061) and aluminium 6061 alloy. SiC volume fraction in composite alloy is 25%. The analysis results stress intensity factor range and 0.1 mm fatigue crack initiation life for SiC$_{w}$/A16061 composite & A16061 matrix are the log-normal distribution. And regression analysis by linear model, exponential model and multiplicative model were performed to find out the relationship between fatigue crack growth rate(da/dN) and stress intensity for find out the relationship between fatigue crack growth rate(da/dN) and stress intensity factor range(.DELTA.K) in the SiC$_{w}$/A16061 composite and examine the applicability of Paris' equation to SiC$_{w}$A16061 composite. Also computer simulation was performed for fatigue life prediction of SiC$_{w}$/A16061 composite using the statistical results of this study.udy.