• 한국생산제조학회지
• /
• 제20권6호
• /
• pp.740-744
• /
• 2011

Carbon-carbon composite material is the reinforced carbon fiber. Because of its high strength, elasticity and the excellent heat-resisting property in high temperature, carbon-carbon composite material has been used in many fields such as aerospace and automotive industries, etc. Especially, aircraft brake discs used at aerospace can be cracked due to its fatigue and vibration under various loading condition. This research is focused on the influence of the vibration of carbon-carbon composite material by using accelerometer with impact hammer excitation. And the change of vibration mode will be known by applying tensile loading test.

• Journal of Mechanical Science and Technology
• /
• 제16권12호
• /
• pp.1652-1663
• /
• 2002

It is desirable to perform nondestructive evaluation to assess material properties and part homogeneity because manufacturing of carbon/carbon (C/C) composites requires complicated and costly processes. In this work several ultrasonic techniques were applied to carbon/carbon composites for the evaluation of spatial variations in material properties that are attributable to the manufacturing process. In a large carbon/carbon composite manufactured by chemical vapor infiltration (CVI) method, the spatial variation of ultrasonic velocity was measured and found to be consistent with the densification behavior in CVI process in order to increase the density of C/C composites. Ultrasonic velocity and attenuation depend on a density variation of materials. Low frequency through-transmission scans based on both amplitude and time-of-flight of the ultrasonic pulse were used for mapping out the material property inhomogeneity These results were compared with that obtained by dry-coupling ultrasonics. Pulse-echo C-scans was used to image near-surface material property anomalies such as the placement of spacers between disks during CVI. Also, optical micrograph had been examined on the surface of C/C composites using a destructive way.

• 공업화학
• /
• 제9권7호
• /
• pp.1065-1069
• /
• 1998

리튬이온 이차전지에 사용되는 탄소부극의 성능을 향상시키기 위하여 결정성계 탄소재료와 비결정성계 탄소재료의 혼합비율에 따른 조합형 탄소전극을 제조하였으며, 이들의 전기화학적 특성과 충방전 특성을 조사하여 조합비율에 따른 리튬의 삽입과 탈삽입 반응기구 및 최적의 조합조건을 찾고자 하였다. 탄소전극은 결정성계 탄소재료인 natural graphite와 $700^{\circ}C$에서 1시간 동안 열처리된 비결정성계 탄소재료인 petroleum cokes를 사용하였다. 조합비에 따라 제조된 조합형 탄소전극은 두 가지 형태의 탄소재료가 갖는 전극특성을 지니며 50:50wt%로 조합하였을 때 가장 우수한 전기화학적 특성과 충 방전 특성을 나타냈다.

• Carbon letters
• /
• 제6권3호
• /
• pp.148-157
• /
• 2005

Carbon/Carbon Composites due to their far superior thermo-mechanical properties are used in a number of demanding applications. However, the material still is used only in specific high tech applications with few exceptions in general industrial applications. The material is extremely expensive and the major challenge is to reduce its cost. Various innovative processing routes are outlined to reduce the cost of processing.

• 한국안전학회지
• /
• 제33권2호
• /
• pp.1-7
• /
• 2018

The multi-scale analysis is more proper and precise for composite materials because of considering the individual microscopic structure and properties of each material for composite materials. The purpose of this study is to verify the validity of using palladium particles in carbon/fiber composites by multi-scale analysis. The palladium is a material for itself to detect leaking hydrogen by using the property of adsorbing hydrogen. The macroscopic model material properties used in this study are homogeneous material properties from microstructure. Homogenized material properties that are calculated from periodic boundary conditions in the microscopic representative volume element model of each macroscopic analysis model. In this study, three macroscopic models were used : carbon fiber/epoxy, carbon fiber/palladium, palladium/epoxy. As a result, adding palladium to carbon/epoxy composite is not a problem in terms of strength.

• Carbon letters
• /
• 제6권4호
• /
• pp.255-256
• /
• 2005

In traditional Chinese medicine, some herbs are used after toasting or roasting. The process is called "Zhi Tan" in Chinese, which means charring, and the herbs after the treatment is called carbon medicine. Carbon medicine is widely used to arrest bleeding in traditional Chinese medicine. The paper introduces the records, development and applications of carbon medicine in ancient China. The earliest record found about carbon medicine was in the remains of Han dynasty (BC206-A.D.8). The paper also introduces the process of charring herbs and mechanism of carbon medicine in arresting bleeding. Calcium iron and tan released during the charring are believed as main factors for arresting bleeding, helped with porous surface structure of active carbon.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
• /
• pp.236-237
• /
• 2005

To measure surface roughness and smoothness of semiconducting materials in power cable, we have investigated the formation and growth process of carbon black showed by changing the content of carbon black. The specimens were primarily kneaded in material samples of pellet form for 5 minutes on rollers ranging between 70[$^{\circ}C$] and 100[$^{\circ}C$]. Then they were produced as sheets after pressing for 20 minutes at 180[$^{\circ}C$] with a pressure of 200[kg/cm]. The contents of conductive carbon black were the variable, and their contents were 20, 30 and 40[wt%], respectively. The surface roughness and smoothness of specimens were measured by SEM and AFM. From SEM experimental result, carbon black in specimens formed matrix as a particles. Also we showed growth process of carbon black according to an increment of the content of carbon black. From AFM experimental result, surface roughness of specimens decreased according to an increment of the content of carbon black.

• 한국기계가공학회지
• /
• 제18권1호
• /
• pp.65-71
• /
• 2019

The development of adsorbed natural gas (ANG) has emerged as one of potential solutions. It is desirable to reduce the weight of vessel by applying light-weighed a composite carbon fiber in order to response to a egulation of $CO_2$ emission. Through understanding of a composite carbon fiber, and material characteristic of a composite carbon fiber is required in order for better application of a reduction of weight and an analysis of material characteristic. Herein, this study suggest the composite carbon fiber vessel applied to the characteristic of carbon fiber, and it decides the preliminary shape based on the test of material characteristic for ANG vessel applied to a composite carbon fiber, and its basic shape calculate through on the netting theory. Moreover, the detail shape design is analyzed by a finite element analysis, and in the stage of detail sahp design and analysis of stress was performed on the typical shape using a finite element analysis, and the result of preliminary design was verified.

• 한국해양공학회지
• /
• 제28권4호
• /
• pp.351-355
• /
• 2014

Today, carbon fibers are used as heating elements. Carbon fibers are generally used to reinforce composite materials because they are lightweight and have a high strength and modulus. Carbon fiber reinforced composite materials are used for aerospace, automobile, and wind turbine blade applications. This work explored the possibility of using carbon fiber reinforced composite materials as self heating materials. The temperatures of the carbon fiber reinforced composites were measured. These results verified that the carbon fiber reinforced composite materials could be used as heating elements. A glass fiber was laminated using various methods. The thermal characteristics of the composites were evaluated. This confirmed that the generation of heat varied according to the lamination thicknesses of the carbon fiber and glass fiber. As the number of carbon fiber laminations increased, the heat-generating temperature increased. In contrast, as the number of glass fiber laminations increased, the amount of heat decreased. The generation of heat and ability to remain warm could be controlled by controlling the carbon fiber and glass fiber laminations.

• 한국재료학회지
• /
• 제24권5호
• /
• pp.243-248
• /
• 2014

Silicon-carbon composite was prepared by the magnesiothermic reduction of mesoporous silica and subsequent impregnation with a carbon precursor. This was applied for use as an anode material for high-performance lithium-ion batteries. Well-ordered mesoporous silica(SBA-15) was employed as a starting material for the mesoporous silicon, and sucrose was used as a carbon source. It was found that complete removal of by-products ($Mg_2Si$ and $Mg_2SiO_4$) formed by side reactions of silica and magnesium during the magnesiothermic reduction, was a crucial factor for successful formation of mesoporous silicon. Successful formation of the silicon-carbon composite was well confirmed by appropriate characterization tools (e.g., $N_2$ adsorption-desorption, small-angle X-ray scattering, X-ray diffraction, and thermogravimetric analyses). A lithium-ion battery was fabricated using the prepared silicon-carbon composite as the anode, and lithium foil as the counter-electrode. Electrochemical analysis revealed that the silicon-carbon composite showed better cycling stability than graphite, when used as the anode in the lithium-ion battery. This improvement could be due to the fact that carbon efficiently suppressed the change in volume of the silicon material caused by the charge-discharge cycle. This indicates that silicon-carbon composite, prepared via the magnesiothermic reduction and impregnation methods, could be an efficient anode material for lithium ion batteries.