• Journal of the Korean Ceramic Society
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• v.25 no.4
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• pp.415-423
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• 1988

Mixtures of carbon and silica (about 0.46${\mu}{\textrm}{m}$) which was synthesized by the hydrolysis of ethyl silicate, the molar ratio of silica/carbon was fixed as 1/10(weight ratio : 1/2), were nitrided in the temperature range 135$0^{\circ}C$~150$0^{\circ}C$. The phse of the product Si3N4 was $\alpha$ phase and the morphology was hexagnoal prism and the nitridation reaction was completed in 5 hrs at 150$0^{\circ}C$ or 7hrs at 145$0^{\circ}C$. The reaction rate above 150$0^{\circ}C$ was diffusion-controlled, following Jander equation. Activation energy Q was derived from the Arrhenius plot and the value was about 101kcal/mol. Axis ratio of Lattice constants(c/a) was 0.726 and unit volume was $\AA$3, the larger the molar ratio of carbon/Alkoxide was, the smaller the particle size of $\alpha$Si3N4 was.

• Journal of the Korean institute of surface engineering
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• v.29 no.6
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• pp.773-780
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• 1996

Silicon oxide films were prepared by using five kinds of organosilicon compound as gas sources without oxygen by rf plasma-enhanced CVD (PECVD). UV light was irradiated on a substrate vertically during deposition to enhance film oxidation and ablation of carbon contamination in a deposited films. Films prepared with UV irradiation contained less carbon than those prepared without UV irradiation. The oxidation of the films was improved by UN irradiation. The effect of UV irradiation was, however, not observed when the films were prepared with tetramethy lsilane (TMS) which contained no oxygen atom. Dissociated oxygen atoms from an organosilicon compound were excited in the plasma with UV irradiation around the substrate surface and affected the enhancement of film oxidation and ablation of carbon in the films.

• Journal of the Korean Ceramic Society
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• v.37 no.3
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• pp.280-287
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• 2000

Adsorption behavior and amount of phenolic resin followed silica (SiO2) formation onto silicon nitride(Si3N4) surface were investigated using electrokinetic sonic amplitude (ESA) technique and with UV spectrometer, to fabricate Si3N4/SiC nano-composite based on reaction between SiO2 formed and phenolic resin absorbed onto Si3N4 particle. The amount of SiO2 formed and carbon from phenolic resin absorbed onto Si3N4 surface were calculated quantitatively to adjust the reaction between SiO2 and phenolic resin, resulting in no residual SiO2 and carbon. As a result, pre-heated tempeature for optimized reaction was below 25$0^{\circ}C$, in which there was no residual SiO2 and carbon.

• Tribology and Lubricants
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• v.16 no.3
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• pp.188-193
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• 2000

An experimental study was performed to discover the effect of environment on the tribological behavior of Si-incorporated diamond-like carbon(Si-DLC) film slid on a steel ball. The films were deposited on Si(100) wafers by a radio-frequency glow discharge of mixtures of benzene and dilute silane gases. Experiments using a ball-on-disk test-rig was performed in vacuum, dry air and ambient air conditions. It was observed that coefficient of friction decreased as the environment changed from vacuum, to dry air. Chemical analyses of debris suggested that low and stable friction is closely related to the formation of silicon-rich oxide debris and the rolling action.

• Journal of the Korean institute of surface engineering
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• v.22 no.3
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• pp.109-117
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• 1989

The effect of heft treatment on the characteristic properties of insulation layer is studied for two kinds of non-oriented silicon steels, which were insulation-coates with various kinds of inorganic and inorganic-organic complex coating solutions. In addition, how the carbon contained in the insulation layer would affect the carbon content and the magnetic properties of the steel substrates is examined. Lower temperature heat treftment ($480^{\circ}C$ for 0.5hr) is found to render morw favorable surface qualities, wheras higher temperature heat treatment ($790^{\circ}C$ for 2hr) better core loss due to grin growt occurred during the heat treatment. Decarburization of the steel substrate is also found unaffectrd by the presence of carbon in the insulation layer.

• Korean Journal of Materials Research
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• v.22 no.12
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• pp.701-705
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• 2012

The effects of clay, aluminum hydroxide, and carbon powder on the sintering of a Si/SiC mixture from photovoltaic silicon-wafer production were investigated. Sintering temperature was fixed at $1,350^{\circ}C$ and the sintered bodies were characterized by SEM and XRD to analyze the microstructure and to measure the apparent porosity, absorptivity, and apparent density. The XRD peak intensity of SiC in the sintered body was increased by adding 5% carbon to the Si/SiC mixture. From this result, it is confirmed that Si in the Si/SiC mixture had reacted with the added carbon. Addition of aluminum hydroxide decreased the cristobalite phase and increased the stable mullite phase. The measurement of the physical properties indicates that adding carbon to the Si/SiC mixture enables us to obtain a dense sintered body that has high apparent density and low absorptivity. The sintered body produced from the Si/SiC mixture with aluminum hydroxide and carbon powder as sintering additives can be applied to diesel particulate filters or to heat storage materials, etc., since it possesses high thermal conductivity, and anticorrosion and antioxidation properties.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1820-1822
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• 2004

In this study, major research fields are classified as ozone generation system for dry cleaning wafer of etched silicon wafer, dry cleaning process of etched silicon wafer which includes SEM analysis and ESCA analysis. The following results are deduced from each experiment and analysis. The magnitudes of carbon and silicon were similar to the survey spectrum of silicon wafer which does not cleaning, but magnitude of oxygen was much bigger Because UV light activates oxygen molecules in the oxide film on the silicon wafer.

• Tribology and Lubricants
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• v.34 no.6
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• pp.313-317
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• 2018

Carbon-based coatings, including carbon nanotubes (CNTs), graphene, and buckyball ($C_{60}$), receive much interest because of their outstanding mechanical and electrical properties for a wide range of electromechanical component-based applications. Previous experimental results demonstrate that these carbon-based coatings are promising solid lubricants because of their superior tribological properties, and thus help prolong the lifetime of silicon-based applications. In this study, CNT coatings are deposited on a bare silicon (100) substrate by electrodynamic spraying under different deposition conditions. During the coating deposition, the applied voltage, CNT concentration of the solution, distance between the injecting nozzle and the substrate and diameter of the injecting nozzle are optimized to control the thickness and surface roughness of the CNT coatings. The surface morphology and thickness of the coatings are characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. The friction and wear properties of the coatings are investigated by using a pin-on-reciprocating-type tribotester under various experimental conditions. The friction coefficient of the CNT coating is as low as 0.15 under high normal loads. The overall results reveal that CNT coatings deposited by electrodynamic spraying provide relatively uniform with superior lubrication performance.

• Clean Technology
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• v.27 no.3
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• pp.223-231
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• 2021

In order to address many issues associated with large volume changes of silicon, which has very low electrical conductivity but offers about 10 times higher theoretical capacity than graphite (Gr), a silicon nanoparticles/hollow carbon (SiNP/HC) composite having bimodal-mesopores was prepared using silica nanoparticles as a template. A control SiNP/C composite without a hollow structure was also prepared for comparison. The physico-chemical and electrochemical properties of SiNP/HC were analyzed by X-ray diffractometry, X-ray photoelectron spectroscopy, nitrogen adsorption/desorption measurements for surface area and pore size distribution, scanning electron microscopy, transmission electron microscopy, galvanostatic cycling, and cyclic voltammetry tests to compare them with those of the SiNP/C composite. The SiNP/HC composite showed significantly better cycle life and efficiency than the SiNP/C, with minimal increase in electrode thickness after long cycles. A hybrid composite, SiNP/HC@Gr, prepared by physical mixing of the SiNP/HC and Gr at a 50:50 weight ratio, exhibited even better cycle life and efficiency than the SiNP/HC at low capacity. Thus, silicon/carbon composites designed to have hollow spaces capable of accommodating volume expansion were found to be highly effective for long cycle life of silicon-based composites. However, further study is required to improve the low initial coulombic efficiency of SiNP/HC and SiNP/HC@Gr, which is possibly because of their high surface area causing excessive electrolyte decomposition for the formation of solid-electrolyte-interface layers.

• Clean Technology
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• v.28 no.3
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• pp.203-209
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• 2022

An environmental evaluation was conducted by employing LCA methodology for a mechanical seal manufacturing process that uses recycled silicon recovered from end-of-cycle PV modules. The recycled silicon was purified and reacted with carbon to synthesize β-SiC particles. Then the particles underwent compression molding, calcination and heat treatment to produce a product. Field data were collected and the potential environmental impacts of each stage were calculated using the LCI DB of the Ministry of Environment. The assessment was based on 6 categories, which were abiotic resource depletion, acidification, eutrophication, global warming, ozone depletion and photochemical oxidant creation. The environmental impacts by category were 45 kg CO₂ for global warming and 2.23 kg C₂H₄ for photochemical oxide creation, and the overall environmental impact by photochemical oxide creation, resource depletion and global warming had a high contribution of 98.7% based on weighted analysis. The wet process of fine grinding and mixing the raw silicon and carbon, and SiC granulation were major factors that caused the environmental impacts. These impacts need to be reduced by converting to a dry process and using a system to recover and reuse the solvent emitted to the atmosphere. It was analyzed that the environmental impacts of resource depletion and global warming decreased by 53.9% and 60.7%, respectively, by recycling silicon from end-of-cycle PV modules. Weighted analysis showed that the overall environmental impact decreased by 27%, and the LCA analysis confirmed that recycling waste modules could be a major means of resource saving and realizing carbon neutrality.