• 한국재료학회지
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• 제10권4호
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• pp.276-281
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• 2000

Si(111) 표면을 NH$_3$분위기에서 실리콘질화물(SiNx)로 변형시킨 후 탄화규소(silicon carbide, SiC) 박막을 성장하였다. 질화시간이 증가함에 따라 SiC 박막 두께가 감소함을 관찰하였다. 또한 성장변수에 따라 SiC/Si 계면에서 결정결함인 틈새를 없앨 수 있었다. 100nm, 300nm, 500nm의 SiNx/Si 기판 위에 SiC 박막을 성장시켰다. 성장된 SiC 박막들은 모두 [111]면을 따라 성장되었고, SiC 결정들이 원주형 낟알로 성장되었다. SiC/SiNx 계면에서 void를 관찰할 수 없었다. 이러한 실험 결과는 SOI 구조의 산화규소를 SiNx로 대체함으로써 SiC 소자 제작에 응용될 수 있는 방향을 제시하고 있다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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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.

• 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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• 제36권6호
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• pp.655-661
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• 1999

${\beta}$-SiC formation mechanism in Si melt-C-SiC system with varying in size of carbon source was investigated. A continuous reaction sintering process using Si melt infiltration method was adopted to control the reaction sintering time effectively. It was found that ${\beta}$-SiC formation mechanism in Si melt-C-SiC system was directly affected by the size of carbon source. In the Si melt-C-SiC system with large carbon source ${\beta}$-SiC formation mechanism could be divided into two stages depending on the reaction sintering time: in early stage of reaction sintering carbon dissolution in Si melt and precipitation of ${\beta}$-SiC was occurred preferentially and then SIC nucleation and growth was controlled by diffusion of carbon throughy the ${\beta}$-SiC layer formed on graphite particle. Furthmore a dissolution rate of graphite particles in Si melt could be accelerated by the infiltration of Si melt through basal plane of graphite crystalline.

• 대한기계학회논문집A
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• 제31권2호
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• pp.205-210
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• 2007

SiC/SiC composites and monolithic SiC materials have been fabricated by the melt infiltration process, through the creation of crystallized SiC phase by the chemical reaction of C and Si. The reinforcing material used in this system was a braided Hi-Nicalon SiC fiber with double interphases of BN and SiC. The microstructures and the mechanical properties of RS-SiC based materials were investigated through means of SEM, TEM, EDS and three point bending test. The matrix morphology of RS-SiS/SiC composites was greatly composed of the SiC phases that the chemical composition of Si and C is different. The TEM analysis showed that the crystallized SiC phases were finely distributed in the matrix region of RS-SiC/SiC composites. RS-SiC/SiC composites also represented a good flexural strength and a high density, accompanying a pseudo failure behavior.

• 한국재료학회지
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• 제25권5호
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• pp.258-263
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• 2015

To fabricate porous SiC-Si composites for heating element applications, both SiC powders and Si powders were mixed and sintered together. The properties of the sintered SiC-Si body were investigated as a function of SiC particle size and/or Si particle contents from 10 wt% to 40 wt%, respectively. Porous SiC-Si composites were fabricated by Si bonded reaction at a sintering temperature of $1650^{\circ}C$ for 80 min. The microstructure and phase analysis of SiC-Si composites that depend on Si particle contents were characterized using scanning electron microscope and X-ray diffraction. The electrical resistivity of SiC-Si composites was also evaluated using a 4-point probe resistivity method. The electrical resistivity of the sintered SiC-Si body sharply decreased as the amount of Si addition increased. We found that the electrical resistivity of porous SiC-Si composites is closely related to the amount of Si added and at least 20 wt% Si are needed in order to apply the SiCSi composites to the heating element.

• 한국결정성장학회지
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• 제6권1호
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• pp.62-72
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• 1996

SiC와 금속박막간의 계변형성 및 반응 생성물의 구조가 $5500^{\circ}C$에서 $1450^{\circ}C$의 온도 범위에서 조사되어졌다. SiC와 코발트간의 반응에 있어서 전형척인 반응충의 순서는 $1050^{\circ}C$에서 $1250^{\circ}C$까지의 온도 범위에서 CoSi/CoSi+C/CoSi/CoSi+C/ $\cdots$ /SiC이었고, SiC와 니켈간의 반응에 있어셔 전형적인 반응충의 순셔는 $950^{\circ}C$에서 $1050^{\circ}C$까지의 온도 범위에서 $Ni_2Si/Ni_2Si+C/Ni_2Si/Ni_2Si+C/ {\cdots} /SiC$이었다. 탄소의 결정화가 SiC / Co 반응에 있어서논 $1450^{\circ}C$ 이상에서 그리고 SiC/Ni 반응에 였어서는 $1250^{\circ}C$ 이상에서 바깐면으로 우선적으로 석출되였다. 또한, 탄 소석출거동을 동반한 주기적인 띠구조의 형성 기구가 열역학적인 고찰을 통하여 논하여졌다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.166-171
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• 2007

The characterization of monolithic SiC and SiCf/SiC composite materials fabricated by NITE and RS processes was investigated in conjunction with the detailed analysis of their microstructure and density. The NITE-SiC based materials were fabricated, using a SiC powder with average size of 30 nm. RS- SiCf/SiC composites were fabricated with a complex slurry of C and SiC powder. In the RS process, the average size of starting SiC particle and the blending ratio of C/SiC powder were $0.4\;{\mu}m$ and 0.4, respectively. The reinforcing materials for /SiC composites were BN-SiC coated Hi-Nicalon SiC fiber, unidirectional or plain woven Tyranno SA SiC fiber. The characterization of all materials was examined by the means of SEM, EDS and three point bending test. The density of NITE-SiCf/SiC composite increased with increasing the pressure holding time. RS-SiCf/SiC composites represented a great decrease of flexural strength at the temperature of $1000\;^{\circ}C.$

• Journal of Welding and Joining
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• 제15권5호
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• pp.104-114
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• 1997

The microstructure and bond strength were investigated on the SiC/SiC and SiC/mild steel joints brazed by Ag-5at%Ti alloy. Ag-5at%Ti-2at%Fe and -5at%Fe brazing alloys were also used to see the effects of Fe addition on the bond strength of SiC/SiC brazed joints. Brazing temperature and brazing gap were selected and examined as brazing variables. The microstructure of SiC/SiC brazed joints was affected by Fe addition to the Ag-5at%Ti alloy, but the bond strength was not. Increasing brazing temperature also changed the microstructure of $Ti_5Si_3$ reaction layer and brazing alloy matrix of the SiC/SiC and SiC/mild steel joints, but not the bond strength. Brazing gap had a great effects on the bond strength. Decreasing brazing gap from 0.2 mm to 0.1 mm in SiC/SiC brazing increased the bond strength from 187 MPa to 263 MPa and, in SiC/mild steel brazing, from 189 MPa to 212 MPa. It was concluded that the most important parameter on the bond strength in SiC/SiC and SiC/mild steel brazing was the relative ratio between brazing gap and specimen size.

• 한국세라믹학회지
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• 제37권2호
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• pp.152-157
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• 2000

Si3N4/SiC nanocomposite ceramics containing 5 wt%dispersed SiC particles were prepared by gas-pressure-sintering at 200$0^{\circ}C$ under nitrogen atmosphere. SiC particles with average sizes of 0.2 and 0.5${\mu}{\textrm}{m}$ were used, and the effect of the SiC particle size on the microstructure was investigated. The addition of SiC particles effectively suppressed the growth of the Si3N4 matrix grains. The effect of grain growth inhibition was higher in the nanocomposites dispersed with fine SiC. SiC particles were dispersed uniformly inside Si3N4 matrix grains and on grain boundaries. When the fine SiC particles were added, large fraction of the SiC particles was trapped inside the grains. On the other hand, when the large SiC particles were added, most of the SiC particles were located on grain boundaries. Typically, the fraction of SiC particles located at grain boundaries was higher in the specimen prepared from $\beta$-Si3N4 than in the specimen prepared from $\alpha$-Si3N4.