• Archives of Metallurgy and Materials
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• 제66권4호
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• pp.941-946
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• 2021

A356 Al composites reinforced by short carbon fiber were prepared through the 2-step process: fabrication of a composite precursor and ultrasonication of the precursor melt. The short carbon fibers were coated with 0.15~1.5 ㎛ thick SiC layer by a carbothermal reaction, and an amount of the carbon fiber reinforcement was determined to be 1.5 vol.% and 4.0 vol.%, respectively. The addition of the carbon fiber increased the hardness of A356 alloy. However, tensile strength did not increase in the as-cast composites regardless of the SiC coating and volume fraction of the carbon fiber, due to the debonding which reduced load transfer efficiency from matrix to fiber at the interface. After T6-treatment of the composites, a significant increase in strength occurred only in the composite reinforced by the SiC-coated short carbon fiber, which was considered to result from the formation of a precipitate improving the Al/SiC interfacial strength.

• Elastomers and Composites
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• 제49권1호
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• pp.66-72
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• 2014

실리카 입자에 팽창흑연을 그라프트 시킴으로 카본코팅을 실시하였으며, 이를 확인하기 위하여 FT-IR, TGA, XPS 그리고 TEM 분석을 실시하였다. 코팅된 흑연의 결정특성은 XRD를 이용하여 확인하였으며, 카본 코팅된 실리카가 SBR 컴파운드의 유변학적 그리고 기계적 성질에 미치는 영향에 대하여 살펴보았다. 카본 코팅된 실리카를 이용한 경우 순수 실리카를 이용한 경우에 비하여 SBR 컴파운드의 유변학적 그리고 기계적 성질이 크게 향상됨을 알 수 있었다. 이러한 현상은 평형팽창비율과 bound 고무 양 변화로도 확인 할 수 있었다.

• 한국환경보건학회지
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• 제31권2호
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• pp.165-171
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• 2005

A laboratory experiment was performed to investigate the nitrate removal from groundwater using Iron chloride(III) coated activated carbon (ICCAC). The breakthrough profiles of two ionic species, such as nitrate and sulfate showed that nitrate was selectively exchanged with chloride in ICCAC. The $FeCl_3$-coated activated carbon produced about 26 BV (Bed volume) of throughout when treating groundwater containing about $25\;mg/\iota\;of\;NO_3-N$. The regeneration of ICCAC with 1M KC1 was effective at a flow rate of 4 BV/hr. The ion exchange technology seems to be suitable technology for the treatment of small volumes of groundwater polluted by nitrate.

• 한국산업융합학회 논문집
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• 제20권2호
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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.

• 전기학회논문지
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• 제65권10호
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• pp.1761-1766
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• 2016

In this paper, we investigated the fusing current of carbon fiber and thermal properties of carbon fiber and metal shielded cable due to over-current. The fusing current value for the metal-coated carbon fiber was 5.3A in 3K, 7.4K and 13.05A in 12K. And if it exceeds 50% of the fusing current was broken with a rapid voltage rise. In the case of carbon fiber shielded cable, the temperature of the PVC sheath increased somewhat in the allowable current range. However, the temperature of PVC sheath rapidly increased to $128.1^{\circ}C$ in the 2 time allowable current range. This value is $10^{\circ}C$ higher than the temperature of PVC sheath on the metal screen cable, because the resistance of the carbon fiber is high and heat transfer rate is slow.

• Applied Microscopy
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• 제45권4호
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• pp.236-241
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• 2015

Carbon-coated Ni, Cu and Sn nanocapsules were investigated by means of X-ray diffraction (XRD), transmission electron microscopy (TEM) and a four-point probe device. All of these nanocapsules were prepared by an arc-discharge method, in which the bulk metals were evaporated under methane ($CH_4$) atmosphere. Three pure metals (Ni, Cu, Sn) were typically diverse in formation of the carbon encapsulated nanoparticles and their different mechanisms were investigated. It was indicated that a thick carbon layers formed on the surface of Ni(C) nanocapsules, whereas a thin shell of carbon with 1~2 layers covered on Cu(C) nanocapsules, and the Sn(C) nanocapsules was, in fact, a longger multi-walled carbon nanotubes partially-filled with metal Sn. As one typical magnetic/dielectric nanocomposite particles, Ni(C) nanocapsules and its counterpart of oxide-coated Ni(O) nanocapsules were compared in the electrically conductive behaviors for further applications as the electromagnetic materials.

• 한국세라믹학회지
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• 제32권9호
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• pp.1003-1008
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• 1995

CVD-Si3N4/CVD-SiC/pack-SiC/pyro-carbon/(3-D C/C composite) multilayer coating was performed to improve the oxdiation resistance and erosion resistance properteis of the 3-D carbon/carbon composite, and the plasma test was performed to measure the oxidation resistance and erosion resistance properties. The thicknesses of each film layer were about 10${\mu}{\textrm}{m}$ for pack-SiC, 5${\mu}{\textrm}{m}$ for CVD-SiC and 40${\mu}{\textrm}{m}$ for CVD-Si3N4. When the multilayer coated specimen was exposed to the plasma flame with temperature of 500$0^{\circ}C$ for 20 seconds, it showed the weight loss five times less than that of the only pyro-carbon coated specimen.

• Composites Research
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• 제29권5호
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• pp.269-275
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• 2016

Multiscale hybrid composites, which consist of polymeric resins, microscale fibers and nanoscale reinforcements, have drawn significant attention in the field of advanced, high-performance materials. Despite their advantages, multiscale hybrid composites show challenges associated with nanomaterial dispersion, viscosity, interfacial bonding and load transfer, and orientation control. In this paper, carbon nanotube(CNT)/carbon fiber(CF)/polycarbonate(PC) multiscale hybrid composite were fabricated by a solution process to overcome the difficulties associated with controlling the melt viscosity of thermoplastic resins. The dependence of CNT loading was studied by varying the method to add CNTs, i.e., impregnation of CF with CNT/PC/solvent solution and impregnation of CNT-coated CF with PC/solvent solution. In addition, hybrid composites were fabricated through surfactant-aided CNT dispersion followed by vacuum filtration. The morphologies of the surfaces of hybrid composites, as analyzed by scanning electron microscopy, revealed the quality of PC impregnation depends on the processing method. Dynamic mechanical analysis was performed to evaluate their mechanical performance. It was analyzed that if the position of the value of tan ${\delta}$ is closer to the ideal line, the adhesion between polymer and carbon fiber is stronger. The effect of mechanical interlocking has a great influence on the dynamic mechanical properties of the composites with CNT-coated CF, which indicates that coating CF with CNTs is a suitable method to fabricate CNT/CF/PC hybrid composites.

• The Plant Pathology Journal
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• 제24권1호
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• pp.58-62
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• 2008

Utilization of carbon sources by Bacillus cereus D324, a biological control agent, and Pythium species, which causes rice seedling disease, was studied with the objective of increasing the efficacy of biological control by providing the biological control agent with specific beneficial carbon sources. D-galactose, D-sorbitol, and D-mannitol were poor carbon sources for Pythium spp. growth but were good for B. cereus D324 growth. Growth in a growth chamber of rice seeds coated with B. cereus D324 amended with specific carbon sources, such as D-galactose and D-sorbitol, showed significantly enhanced seedling emergence compared to seeds coated only with B. cereus D324. Field trials showed that both seedling emergence and yield increased, when the above specific carbon sources were added to B. cereus D324 in seed coating formulations. This result indicated that amending seed coating formulations with specific carbon sources could significantly increase seedling emergence and yield in the field.

• Bulletin of the Korean Chemical Society
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• 제31권6호
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• pp.1506-1508
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• 2010

$LiMnBO_3$ was successfully synthesized by a solid-state reaction method both with and without a carbon coating. Adipic acid was used as source material for the carbon coating. $LiMnBO_3$ was composed of many small polycrystalline particles with a size of about 50 - 70 nm, which showed a very even particle morphology and highly ordered crystalline particulates. Whereas the carbon coated $LiMnBO_3$ was well covered by mat-like, fine material consisting of amorphous carbon derived from the carbonization of adipic acid during the synthetic process. Carbon coated cell exhibited improved and stable discharge capacity profile over the untreated. Two cells delivered an initial discharge capacity of 111 and 58 mAh/g for $LiMnBO_3$/C and $LiMnBO_3$, respectively. Carbon coating on the surface of the $LiMnBO_3$ drastically improved discharge capacity due to the improved electric conductivity in the $LiMnBO_3$ material.