• Korean Journal of Crystallography
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• v.3 no.2
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• pp.98-110
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• 1992

B-SiC thin films were fabricated on Si(100) substrate under 1 atom by fVD. The effects of deposition conditions on the growth and the properties especially crystallinity and prefer ential alignment of these thin films were investigated. SiH4 and CH4 were used as source gases and H2 as Carrier gas. Th9 growth Of B-SiC thin films with changing parameters such as the growth temperature, the ratio of source gases (SiH4/CH4 ) and the total amount of source gases. The grown thin films were characterized by using SEM, a -step, XRD, Raman Spectro- scopy and TEM. Chemical conversion process improved the quality of thin films due to the formation of SiC buffer layer. The crystallinity of SiC thin films was improved when the growth temperature was higher than l150t and the amount of CH4 exceeded that of SiH4. The better crystallinity, the better alignment to the crystalline direction of substates. TEM analyses of the good quality thin films showed that the grain size was bigger at the surface than at the interface and the defect density is not depend on the ratio of the source gases.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.182-185
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• 2004

In this work, the effect of chemical treatments on surface properties of SiC was investigated in mechanical interfacial properties of carbon fibers-reinforced composites. The surface properties of the SiC were determined by acid/base values and contact angles. The thermal stabilities of carbon fibers-reinforced composites were investigated by thermogravimetric analysis (TGA). Also, the mechanical interfacial properties of the composites were studied in interlaminar shear strength (ILSS) and critical strain energy release rate mode II $(G_{IIC})$ measurements. As a result, tile acidically treated SiC (A-SiC) had higher acid value than that of untreated SiC (V-SiC) or basically treated SiC (B-SiC). According to the contact angle measurements, it was observed that chemical treatments led to an increase of surface free energy of the SiC surfaces, mainly due to the increase of the specific (polar) component. The mechanical interfacial properties of the composites, including ILSS and $(G_{IIC})$, had been improved in the specimens treated by chemical solutions. These results were explained that good wetting played an important role in improving the degree of adhesion at interfaces between SiC and epoxy resin matrix.

• Journal of Ocean Engineering and Technology
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• v.20 no.5 s.72
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• pp.77-81
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• 2006

In this study, monolithic liquid phase sintered SiC (LPS-SiC) was made by the hot pressing method with nano-SiC powder, whose particle size is 30 nm and less on the average. Alumina ($Al_{2}O_{3}$), yttria ($Y_{2}O_{3}$), and silica ($S_{i}O_{2}$) were used for sintering additives. To investigate the effects of $S_{i}O_{2}$, the $Al_{2}O_{3}/Y_{2}O_{3}$ composition was fixed and the ratio of $S_{i}O_{2}$ was changed, with seven different ratios tested. And to investigate the effects of the sintering temperature, the sintering temperature was changed, with $1760^{\circ}C,\;1780_{\circ}C$, and $1800_{\circ}C$ being used with a $S_{i}O_{2}$ ratio of 3 wt%. The materials were sintered for 1 hour at $1760^{\circ}C,\;1780^{\circ}C$ and $1800^{\circ}C$ under a pressure of 20 MPa. The effects on sintering from the sintering system used, as well as from the composition of the sintering additives, were investigated by density measurements. Mechanical properties, such as flexural strength, were investigated to ensure the optimum conditions for a matrix of SiCf/SiC composites. Sintered densityand the flexural strength of fabricated LPS-SiC increased with an increase in sintering temperature. Particularly, the relative density of a sintered body at $1800^{\circ}C$ with a non-content of $S_{i}O_{2}$, a specimen of AYSO-1800, was 95%. Also, flexural strength was about 750MPa.

• Composites Research
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• v.33 no.5
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• pp.247-250
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• 2020

In this study, the possibility of manufacturing a magnesium (Mg) composites reinforced with continuous silicon carbide (SiC) fibers was examined using a liquid pressing process. We fabricated uniformly dispersed SiC fiberAZ91 composites using a liquid phase pressing process. Furthermore, the precipitates were controlled through heat treatment. As a continuous Mg₂Si phase was formed at the interface between the SiC fiber and the AZ91 matrix alloy, the interfacial bonding strength was improved. The tensile strength at room temperature of the prepared composite was 479 MPa, showing excellent mechanical properties.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.12
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• pp.863-866
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• 2013

SiC crystal ingots were grown on 6H-SiC dual-seed crystals with different surface roughness and different seed orientation by a PVT (Physical Vapor Transport) method. 4H and 15R-SiC were grown on seed crystal with high root-mean-square (rms) value. The polytype of grown crystal on the seed crystal with lower rms value was confirmed to be 6H-SiC. On the other hand, all SiC crystals grown on seed crystals with different seed orientation were proven to be 6H-SiC. The surface roughness of seed crystals had no effect on the crystal structure of the grown crystals. However, the crystal quality of 6H-SiC single crystals grown on the on-axis seed were revealed to be slightly better than that of 6H-SiC crystal grown on the off-axis seed.

• Composites Research
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• v.35 no.3
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• pp.161-174
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• 2022

SiC fiber-reinforced SiC matrix composite is a promising accident-tolerant fuel cladding material to improve the safety of light water nuclear reactors. Compared to the current zirconium alloy fuel cladding as well as metallic accident-tolerant fuel cladding, SiC composite fuel cladding has exceptional accident-tolerance such as excellent structural integrity and extremely low corrosion rate during severe accident of light water nuclear reactors, which reduces reactor core temperature and delays core degradation processes. In this paper, we introduce the concept, technical issues, and properties of SiC composite accident-tolerant fuel cladding during operation and accident scenarios of light water nuclear reactors.

• Journal of the Korean Ceramic Society
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• v.44 no.7
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• pp.381-386
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• 2007

A porous reaction bonded silicon carbide (RBSC) was fabricated by a molten Si infiltration method. The porosity and flexural strength of porous RBSC fabricated in this study were dependent upon the amount of carbon source used in the SiC/carbon preform as well as the amount of Si infiltrated into the SiC/carbon preform. The porosity and flexural strength of porous RBSC were in the range of $20 vo1.{\sim}49 vo1.%$ and $38{\sim}61 MPa$, respectively. With increase of carbon contents and molten Si for infiltration, volume fraction of the pores was gradually decreased, and flexural strength was increased. The porous RBSCs fabricated with the same amount of molten Si show less residual Si around neck with increase of carbon source, as well as a new SiC was formed around neck which resulted in the decreased porosity and improvement of the flexural strength. In addition, decrease of the porosity and increase of the flexural strength were also obtained by increase of the amount of molten Si with the same amount of carbon source. However, it was found that the flexural strength of porous RBSC depends on the porosity rather than the amount of the newly formed SiC in neck phase between SiC particles used as a starting material.

• Journal of the Korean Ceramic Society
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• v.22 no.4
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• pp.26-32
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• 1985

The subcritical crack growth of sintered SiC is investigated under various corrosive atmospheres such as distilled water Murakami solution and saturated KOH solution. The KI-V diagrams are obtained by the load relaxation method and incremental displacement rate method using the double torsion technique. The obtained fracture mechanics parameters (n) of sintered SiC are 79 in Murakami solution and 39 in saturated KOH solution. These data indicate that the subcritical crack growth of sintered SiC is taking place in these two conditions and the stress-corrosion cracking is suggested to be the mechanism. With these KI-V diagrams the life of sintered SiC in these conditions is predicted.

• Journal of Surface Science and Engineering
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• v.47 no.6
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• pp.354-361
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• 2014

In order to utilize silicon carbide (SiC) as an inner part of fluidized bed reactor (FBR) for manufacturing poly-silicon, we have carried out the thermodynamic calculation on the overall reactions including poly-silicon synthesis and compatibility of SiC with FBR process. The resources of silicon included $SiH_4(MS)$, $SiHCl_3(TCS)$ and $SiCl_4(STC)$ and the thermodynamic yield of the FBR with MS, TCS and STC were compared each other with variable range of temperature, pressure and hydrogen to silicon ratio. The silicon yield of MS, TCS and STC were 100%, 28% and 4%, respectively, throughout the conventional FBR conditions. Silicon carbide having high hardness and strength showed strong resistance to granule collisions during the FBR process using a lab-scale reactor. And it also showed quite good compatibility with the typical FBR processes of MS and TCS resources.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.9
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• pp.767-773
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• 2016

A Weibull statistical analysis of the mechanical properties of SiC ceramics was carried out by immersion in acidic and alkaline solutions. The heat treatment was carried out at 1373 K. The corrosion of SiC was carried out in acidic and alkaline solutions under KSL1607. The bending strength of corroded crack-healed specimens decreased 47% and 70% compared to those of uncorroded specimens in acidic and alkaline solutions, respectively. The corrosion of SiC ceramics is faster in alkaline solution than in acid solution. The scale and shape parameters were evaluated for the as-received and corroded materials, respectively. The shape parameter of the as-received material corroded in acidic and alkaline solutions was significantly more apparent in the acidic solution. Further, the heat-treated material was large in acidic solution but small in alkaline solution. The shape parameters of the as-received and heat-treated materials were smaller in both acidic and alkaline solutions.