• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.181-184
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• 2006

Nano Infiltration Transient Eutectic Phase - Silicon Carbide (NITE-SiC) and $SiC_f/SiC$ composite have been fabricated by a Hot Pressing (HP) process, using SiC powder with an average size of about 30nm. Alumina ($Al_2O_3$) and Yttria ($Y_2O_3$) were used for additives materials. These mixed powders were sintered at the temperature a of $1300^{\circ}C$, $1650^{\circ}C$, $1800^{\circ}C$ and $1900^{\circ}C$ under an applied pressure of 20MPa. And unidirection and two dimension woven structures of $SiC_f/SiC$ composites were prepared starting from Tyranno SA fiber. Densification of microstructure gives an effect to density. Specially, Densification Mechanism basically is important from the sintering which use the HP. In this study, the densification of NITE-SiC and $SiC_f/SiC$ composite mechanism by a press displacement appears investigated. The mechanism on the densification of each sintering temperature was investigated. The each step is shows a with each other different mechanism quality.

• Proceedings of the Korean Ceranic Society Conference
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• 2000.04a
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• pp.22.1-22.1
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• 2000

• Proceedings of the Korean Ceranic Society Conference
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• 2003.10a
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• pp.121.1-121
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• 2003

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.9
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• pp.1757-1763
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• 2009

The composites were fabricated by adding 0, 15, 20, 25[vol.%] Zirconium Diboride(hereafter, $ZrB_2$) powders as a second phase to Silicon Carbide(hereafter, SiC) matrix. The physical, mechanical and electrical properties of electroconductive SiC ceramic composites by Spark Plasma Sintering(hereafter, SPS) were examined. Reactions between ${\beta}-SiC$ and $ZrB_2$ were not observed in the XRD analysis. The relative density of mono SiC, SiC+15[vol.%]$ZrB_2$, SiC+20[vol.%]$ZrB_2$ and SiC+25[vol.%]$ZrB_2$ composites are 90.93[%], 74.62[%], 74.99[%] and 72.61[%], respectively. The XRD phase analysis of the electroconductive SiC ceramic composites reveals high of SiC and $ZrB_2$ and low of $ZrO_2$ phase. The lowest flexural strength, 108.79[MPa], shown in SiC+15[vol.%] $ZrB_2$ composite and the highest - 220.15[MPa] - in SiC+20[vol.%] $ZrB_2$composite at room temperature. The trend of the mechanical properties of the electroconductive SiC ceramic composites moves in accord with that of the relative density. The electrical resistivities of mono SiC, SiC+15[vol.%]$ZrB_2$, SiC+20[vol.%]$ZrB_2$ and SiC+25[vol.%]$ZrB_2$ composites are 4.57${\times}10^{-1}$, 2.13${\times}10^{-1}$, 1.53${\times}10^{-1}$ and 6.37${\times}10^{-2}$[${\Omega}$ cm] at room temperature, respectively. The electrical resistivity of mono SiC, SiC+15[vol.%]$ZrB_2$. SiC+20[vol.%]$ZrB_2$ and SiC+25[vol.%]$ZrB_2$ are Negative Temperature Coefficient Resistance(hereafter, NTCR) in temperature ranges from 25[$^{\circ}C$] to 100[$^{\circ}C$]. The declination of V-I characteristics of SiC+20[vol.%]$ZrB_2$ composite is 3.72${\times}10^{-1}$. It is convinced that SiC+20[vol.%]$ZrB_2$ composite by SPS can be applied for heater or electrode above 1000[$^{\circ}C$]

• Composites Research
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• v.36 no.3
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• pp.167-172
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• 2023

The manufacturing technology of composite material is applicable with filler characteristics maintaining low cost, flexibility, and easy process to develope the various functional composite materials. To realize functional composites, various researches on the high performance of composite materials using graphene as a filler is being actively conducted. In this study, physical and chemical properties were investigated using graphene to improve high functional properties. Graphene oxide (GO) was prepared using graphane nanoplatelet (GNP), and reduced graphene oxide (R-GO) was formed by reducing GO. The physical properties of GO and R-GO were analyzed, and the reliability of the manufactured method was reviewed by comparing that of GNP results. As a result of analysis by Raman spectroscopy, in the case of R-GO, it was confirmed that the intensity of D-peak and G-peak decreased compared to GO, and an increase of 0.08 was observed through the ratio of ID/IG. For the FTIR results, GO and RGO has a repeating C-C and C=C connection structure unlike GNP. GO and R-GO show clear peaks for C-O bond, C=C bond, C=O bond, and O-H bonding. As a result of X-ray diffraction analysis, GNP showed a wide diffraction peak at 25.86° of (002) plane characteristics, whereas GO and R-GO showed peaks corresponding to (001) and (100) planes. It was also found that the interlayer distance of GO increased by about 2.6 times compared to GNP.

• Journal of Electrical Engineering and Technology
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• v.4 no.4
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• pp.538-545
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• 2009

The SiC-$ZrB_2$ composites were fabricated by combining 30, 35, 40 and 45vol.% of Zirconium Diboride (hereafter, $ZrB_2$) powders with Silicon Carbide (hereafter, SiC) matrix. The SiC-$ZrB_2$ composites, the sintered compacts, were produced through Spark Plasma Sintering (hereafter, SPS), and its physical, electrical, and mechanical properties were examined. Also, the thermal image analysis of the SiC-$ZrB_2$ composites was examined. Reactions between $\beta$-SiC and $ZrB_2$ were not observed via X-Ray Diffractometer (hereafter, XRD) analysis. The relative density of the SiC+30vol.%$ZrB_2$, SiC+35vol.%$ZrB_2$, SiC+40vol.%$ZrB_2$, and SiC+45vol.%$ZrB_2$ composites were 88.64%, 76.80%, 79.09% and 88.12%, respectively. The XRD phase analysis of the sintered compacts demonstrated high phase of SiC and $ZrB_2$ but low phase of $ZrO_2$. Among the SiC-$ZrB_2$ composites, the SiC+35vol.%$ZrB_2$ composite had the lowest flexural strength, 148.49MPa, and the SiC+40vol.%$ZrB_2$ composite had the highest flexural strength, 204.85MPa, at room temperature. The electrical resistivities of the SiC+30vol.%$ZrB_2$, SiC+35vol.%$ZrB_2$, SiC+40vol.%$ZrB_2$ and SiC+45vol.%$ZrB_2$ composites were $6.74\times10^{-4}$, $4.56\times10^{-3}$, $1.92\times10^{-3}$, and $4.95\times10^{-3}\Omega{\cdot}cm$ at room temperature, respectively. The electrical resistivities of the SiC+30vol.%$ZrB_2$, SiC+35vol.%$ZrB_2$ SiC+40vol.%$ZrB_2$ and SiC+45[vol.%]$ZrB_2$ composites had Positive Temperature Coefficient Resistance (hereafter, PTCR) in the temperature range from $25^{\circ}C$ to $500^{\circ}C$. The V-I characteristics of the SiC+40vol.%$ZrB_2$ composite had a linear shape. Therefore, it is considered that the SiC+40vol.%$ZrB_2$ composite containing the most outstanding mechanical properties, high resistance temperature coefficient and PTCR characteristics among the sintered compacts can be used as an energy friendly ceramic heater or electrode material through SPS.

• Korean Journal of Materials Research
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• v.4 no.8
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• pp.945-951
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• 1994

In order to elucidate the extrusion characteristics of $SiC_{p}$/6061 Al composite, defomation resistance, $K_{w}$ was determined using the empirical formula suggested by Watanabe et al, and also extrusion pressure was measured using the extrusion press with a capacity of 350 ton. The $K_{w}$ which are propotional to extrudability, was increased with increasing volume fraction of reinforcement, $SiC_{p}$, but decreased with increasing the particle size. The peaks of maximum extrusion pressure in curves of extrusion force vs ram stroke were changed sharply with decreasing the particle size. The elevated extrustion temperature resulted in the decreased $K_{w}$ and extrusion pressure, but caused the surface tearing of extrusion composite bars. The results showed that extrudability of the composite billets is depend on the extrusion conditions as well as the characteristics of reinforcement, $SiC_{p}$.

• Composites Research
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• v.32 no.3
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• pp.158-162
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• 2019

Titanium carbide (TiC) reinforced Inconel 718 matrix composites were successfully fabricated by a novel liquid pressing infiltration process. Microstructure and mechanical properties of the fabricated 55 vol% TiC-Inconel 718 composite are analyzed. The composite exhibits superior mechanical properties, such as hardness and compressive strength as compared with Inconel 718. It is believed that Mo and Nb, which are alloying elements in the matrix, diffuse and solidify into the TiC reinforcement, resulting in generation of core-rim structure with excellent interfacial properties.

• Restorative Dentistry and Endodontics
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• v.16 no.1
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• pp.60-73
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• 1991

The purpose of this study is to evaluate the effects of etching time, environmental temperature and humidity on the adhesion of composite resin to glass-ionomer cement. Two chemical cure composite resins (Clearfil F II and Microrest AP) and two glass-ionomer cements (Fuji ionomer Type I and KET AC-CEM) were used as the experimental materials. The experiment is performed in 3 stages: The first stage is to bond composite resins to glass-ionomer cements, and the surface was not etched, and etched for 20 seconds, 40 seconds, and 60 seconds. Then specimens are stored in distilled water at $37^{\circ}C$ for 24 hours to measure tensile strength. The second stage is to choose the one group that had the highest tensile strength from the first stage and prepare two experimental groups: One group with composite resin bonded to glass-ionomer cement without etching and bonding agent application and the other with composite resin bonded to glass-ionomer cement with etching but without any bonding agent application. The specimens are stored in distilled water at $37^{\circ}C$ for 24 hours and tensile strength is measured. The third stage is to choose group that had the highest tensile strength from the first stage experiment, and bond composite resin to glass-ionomer cement at $24^{\circ}C$ 44%, $30^{\circ}C$ 44%, $30^{\circ}C$ 80%, and $32^{\circ}C$ 92%. The storage time of specimens is to bond immediately after storage, then changed to 30 sec., 60 sec., and 120 sec.. Specimens are stored in distilled water at $37^{\circ}C$ for 24 hours and their tensile strength are measured again. The following results were obtained: 1. As the etching time increases, the tensile bond strength between glass-ionomer cement and composite resin increase, and the tensile bond strength is the highest when acid etched for 60 minutes (P < 0.05). 2. After acid etching for 60 minutes, the tensile strength of the group with bonding agent was stronger than that without bonding agent application (P < 0.05). 3. The tensile strength of Clearfil F II was stronger than that of Microrest AP. 4. It was observed that the tensile bond strength is not affected by different storage time with different temperature and humidity. 5. As the humidity was increased, the tensile bond strength between glass-ionomer cement and composite resin decreased (P < 0.05).

• Journal of Korea Foundry Society
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• v.14 no.5
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• pp.429-437
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• 1994

Influence of interfacial structure between matrix and particle in A356/coated SiC composite fabricated by squeeze casting method was studied. Experimental variables are types of coated metallic film on SiC particles such as Cu, Ni-P, and applied pressure for squeeze casting. It was found that coating treatment on SiC particles improves the wetting of liquid A356 alloy on SiC particles. SiC particle distribution is very homogeneous in A356 matrix alloy which is fabricated by squeeze casting. Analysing the surface morphology of fractured A356/coated SiC, it was concluded that metallic thin film by coating treatment on SiC particle improves the interfacial bonding between particle and matrix, and so does on mechanical properties such as tensile strength. However, there was on significant difference in hardness between those composite made of as-received SiC particle and coated SiC particle.