• Carbon letters
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• v.2 no.3_4
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• pp.165-169
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• 2001

Modification of C/C composite bipolar plate for improving electrical conductivity was carried out by addition of electroconductive carbon black (EC-CB). Carbon black was carefully mixed to methanol-containing phenolic resin, impregnated into 2D-carbon fabrics, hot pressed and then carbonized to obtain composite plate. Inclusion of electro-conductive carbon black enhanced the electrical conductivity of the C/C composites by increasing the conduction path. Addition of 10 vol% carbon black increased the electrical conductivity from 5.5/${\Omega}cm$ to 32/${\Omega}cm$ and reduced the crack formation by filling effect, resulting in the increase of flexural properties of composite plate. However, at carbon black content over 10 vol%, flexural properties decreased by delaminating role of excess carbon black at the interface in C/C composites.

• Corrosion Science and Technology
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• v.7 no.6
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• pp.301-306
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• 2008

Surface composite layers of 1.9~2.9 mm in thickness were fabricated by depositing metamorphic powders on a carbon steel substrate and by irradiating with a high-energy electron beam. In the surface composite layers, 48~64 vol.% of $Cr_{2}B$ or $Cr_{1.65}Fe_{0.35}B_{0.96}$ borides were densely precipitated in the austenite or martensite matrix. These hard borides improved the hardness of the surface composite layer. According to the otentiodynamic polarization test results of the surface composites, coatings, STS304 stainless steel, and carbon steel substrate, the corrosion potential of the surface composite fabricated with 'C+' powders was highest, and its corrosion current density was lowest, while its pitting potential was similar to that of the STS304 steel. This indicated that the overall corrosion resistance of the surface composite fabricated with 'C+' powders was the best among the tested materials. Austenite and martensite phases of the surface composites and coatings was selectively corroded, while borides were retained inside pits. In the coating fabricated with 'C+' powders, the localized corrosion additionally occurred along splat boundaries, and thus the corrosion resistance of the coating was worse than that of the surface composite.

• Journal of the Korean Society for Heat Treatment
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• v.22 no.3
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• pp.149-154
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• 2009

Dense $5Cu_{0.6}Fe_{0.4}-Al_2O_3$ composite was consolidated from mechanically synthesized powders by pulsed current activated sintering method within 1 min. $5Cu_{0.6}Fe_{0.4}-Al_2O_3$ powder was synthesized from 3CuO and 2FeAI using the high energy ball milling. Dense $5Cu_{0.6}Fe_{0.4}-Al_2O_3$ with relative density of up to 95% was produced under simultaneous application of a 80 MPa pressure and the pulsed current. Mechanical properties and grain size of the composite were investigated.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.844-845
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• 2006

For microelectronic circuits, the main type of failure is thermal fatigue. Therefore, the search for matched coefficients of thermal expansion (CTE) of packaging materials in combination with a high thermal conductivity is the main task for developments of heat sink materials electronics, and good mechanical properties are also required. The aim of this work is to develop copper matrix composites reinforced with carbon nanofibers to meet these requirements. In this paper, a technology for obtaining a homogeneous mixture of copper and nanofibers will be presented and the microstructure and properties of consolidated samples will be discussed.

• International Journal of Aerospace System Engineering
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• v.10 no.1
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• pp.14-24
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• 2023

The materials applied to the aircraft fuselage, parts, and components must be verified by relative authorities in accordance with the procedures set by the airworthiness authority to achieve the aircraft type certification. There are no examples of domestic composite materials which were verified in order to be applied to aircraft structure. In this study, the composite material certification system of NCAMP, an American composite material standard certification organization, was reviewed and used as the fundamentals of the first aerospace composite material certification system in ROK(Fig 2,8). Also updated material certification documents were developed and confirmed by material certification engineers and inspectors. This aerospace composite material qualification system is intended to modernize the material certification system for AAM(Advanced Air Mobility) as well as aircraft and to enhance the understanding of related technicians and inspectors.

• Ceramist
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• v.22 no.2
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• pp.110-121
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• 2019

Triboelectric nanogenerators and piezoelectric nanogenerators are a spotlighted energy harvesting method that converts the wasted mechanical energy from the environment into usable electrical energy. In the case of triboelectric nanogenerators, researches have been mainly focused on high permittivity and flexible polymer materials, and in the case of piezoelectric nanogenerators, researches have been focused on ceramic materials exhibiting high polarization characteristics. Recently, many researches have been conducted to improve durability and power in various environments by using composite materials which have flexible properties of polymer, high permittivity, thermal resistance and high polarization properties of ceramics. This article reviews the energy harvesting studies reported about composites materials using ceramics and polymers.

• The magazine of the Korean Society for Advanced Composite Structures
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• v.4 no.1
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• pp.9-13
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• 2013

• Journal of the Korean Ceramic Society
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• v.45 no.2
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• pp.119-125
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• 2008

The FAS(Fluoroalkylsilane)/Nafion inorganic-organic composite electrolyte membrane was successfully fabricated through sol-gel method. The FAS having hydrophobic functional group and silanol ligands is impregnated in $Nafion^{(R)}$ membrane to reduce methanol crossover. The prepared FAS/Nafion inorganic-organic composite electrolyte membrane consist of the hydrophobic FAS-derived silicate nano-particles and $Nafion^{(R)}$ matrix showed decrease of methanol crossover and reduction of humidity dependence without large sacrifice of proton conductivity. The microstructural analysis of the composite membranes was performed using FESEM and FTIR. And the effect of the incorporation of the hydrophobic FAS-derived silicate nano-particles into $Nafion^{(R)}$ membrane was investigated via solvent uptake, membrane expansion rate, humidity dependency of proton conductivity and contact angle measurement.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.5-13
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• 2006

Based on the inventions of continuous ceramic fibers, such as C, SiC, $Al_2O_3$ etc., by polymer precursor driven methods, there have been many efforts to fabricate ceramic continuous fiber reinforced composite materials with metals and ceramics matrices. The main purpose of the R & D efforts has been to produce materials for severe environments, including advanced energy systems, advanced transportation systems. The efforts have been started from the R & D of metal matrix composite materials and now the strong emphasis on ceramic matrix composites R & D can be recognized. This paper provides a brief review about the national efforts to establish advanced composite materials for future industries starting from mid 70s. C/Al and SiC/Al are the typical examples to be applied transportation systems and energy systems. The excellences in specific strength and overall mechanical properties, the excellences in environmental resistance make those materials as potential materials for advanced ocean construction and marine transportation systems. About the recent progress in ceramic fiber reinforced ceramic composites, advanced SiC/SiC composites including NITE-SiC/SiC will be introduced and the present status will be introduced.

• The magazine of the Korean Society for Advanced Composite Structures
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• v.3 no.4
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• pp.10-17
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• 2012