• Journal of the Korean Ceramic Society
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• v.34 no.11
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• pp.1151-1158
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• 1997

Fracture of uni-directional carbon fiber reinforced carbon matrix composite is strongly dependent on the orientation of basal plane in graphite matrix when it is limited within matrix. The orientation of basal planes are vertically stacked to carbon fiber which results in the weakness for applied tensile or shear force in thermosetting resin derived-carbon matrix composite. Microtextural control of the matrix was tried through chemical interaction between metal carbides and furan resin derived-carbon matrix. SiC and TiO2 addition made the orientation disordered. However, porosity increased due to decomposition of SiC. Interfacial bonding could be controlled by TiO2 addition, but carbon fiber was considerably reacted with TiC during thermal treatment higher than 2$600^{\circ}C$. Therefore, it is desirable to control the thermal treatment temperature at which decomposition of SiC was not serious and TiC/C was not formed eutectoid.

• Journal of the Korean Ceramic Society
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• v.27 no.2
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• pp.265-273
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• 1990

Fine Si-Al-OH-C coprecipitate powders were prepared from Si(OC2H5)4, Al(i-OC3H7)3, and carbon black by a hydrolysis method before fabrication of Sialon-SiC composite powder by carbothermal reduction at 1350$^{\circ}C$ for 10h under N2/H2 mixed atmosphere. The characterization of the synthesized Sialon-SiC composite powders was performed using XRD, BET, SEM, TEM and particle size analysis methods. The average particle size and specific surface area of the synthesized Sialon-SiC composite powder were 0.13$\mu\textrm{m}$ and 20.1㎡/g, respectively when Z=1 and N2 : H2=50 : 50.

• Journal of the Korean Ceramic Society
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• v.32 no.9
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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.

• Journal of the Korean Ceramic Society
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• v.43 no.8 s.291
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• pp.509-514
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• 2006

In this study, chopped Hi-Nicalon SiC fiber Reinforced Porous Reaction Bonded SiC (RBSC) composites and it fabrication process were developed by using Si melt infiltration process. The porosity and average pore size in fabricated chopped SiC fiber reinforced porous RBSC composites were in the range of $30{\sim}40%$ and $40-90{\mu}m$, which mainly determined by the SiC powder size used as starting material and amount of residual Si in porous composites. The maximum flexural strength of chopped SiC fiber reinforced porous RBSC composite was as high as 80 MPa. The delayed fracture behavior was observed in chopped SiC fiber reinforced porous RBSC composites upon 3-point bending strength test.

• Journal of the Korean Ceramic Society
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• v.29 no.10
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• pp.757-764
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• 1992

The platelet reinforced mullite-zirconia composites were prepared by pressurelss sintering with addition of Al2O3 or SiC platelets. The sintered density of 10 vol% Al2O3 platelet reinforced mullite-zirconia composite was 98.3% at 1700$^{\circ}C$. The fracture strength (290 MPa) and fracture toughness (4.9 MPa$.${{{{ SQRT { m} }}) in the Al2O3 platelet reinforced mullite-zirconia composite were enhanced compared with those of mullite-zirconia due to the crack deflection and load transfer effect of platelets. Whereas, the SiC platelet reinforced mullite-zirconia composite sintered at 1650$^{\circ}C$ showed relatively lower density (95.7%), fracture strength (170 MPa), and fracture toughness (3.9 MPa$.${{{{ SQRT { m} }} than the Al2O3 platelet reinforced mullite-zirconia composite.

• Journal of the Korean Ceramic Society
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• v.30 no.8
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• pp.678-684
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• 1993

Alumina composite membranes were prepared by chemical vapor deposition and evaporation-oxidation process. For CVD process, deposition was carried out using aluminum-tri-isopropoxide at 35$0^{\circ}C$, 2 torr by heterogeneous reaction, and for evaporation-oxidation process, alumina composite membranes were prepared by evaporation of aluminum and dry oxidation at 80$0^{\circ}C$. As deposition time increases, water flux and N2 gas permeability of the composite membranes prepared by both processes were reduced. Applying gas permeation model, permeability and cracking possibility of top layer were evaluated.

• The Korean Journal of Ceramics
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• v.1 no.4
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• pp.219-223
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• 1995

Ceramic membranes of the supported $TiO_2-CeO_2$ were prepared by dip-coating method on an $\alpha-Al_2O_3$ porous substrate. The mean pore diameter of an alumina support was 0.125 um. The mean particle diameter of $TiO_2-CeO_2$ top layer varied with firing temperature and ranged from 20 to 85 nm. The thermal stability of the composite membranes was studied from their surface microstructure after calcination at $600-900^{\circ}C$. The supported $TiO_2-CeO_2$ composite membranes exhibited much higher heat resistance than the $TiO_2$ membrane.

• Journal of Ceramic Processing Research
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• v.19 no.6
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• pp.455-460
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• 2018

Chromium plating is a common surface treatment technique extensively applied in industry due its excellent properties which include substantial hardness, abrasion resistance, corrosion resistance, surface color, and luster. In this study, the effect of PTFE on corrosion behavior of Cr-P plating, low carbon steel substrates are electroplated in Cr(III) baths without and with PTFE. Trivalent chromium carbon plating was electroplated from trivalent chromium sulfate-based baths with different PTFE dispersion contents. The study focused on the microstructure, PTFE content, roughness, and corrosion resistance of the Cr-P-PTFE composite plating. Scanning electron microscopy and atomic force microscopy images showed a smoother plating and a decrease in the surface roughness of the electrodeposited. The results demonstrate that PTFE eliminates the cracks within plating by reducing internal stress. Therefore, the corrosion resistance of Cr-P-PTFE composite platings were better than that of Cr-P alloy platings.

• Membrane and Water Treatment
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• v.10 no.6
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• pp.431-440
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• 2019

A novel composite membrane was synthesized using crosslinked polyamide and fly ash ceramic substrate for phenol removal. Glutaraldehyde was used as crosslinker. Characterization shows that synthesized membrane possesses good permeability ($0.184l.m^{-2}.h^{-1}.kPa^{-1}$), MWCO (1.7 kDa), average pore size (1.08 nm) and good chemical stability. RSM was adopted for phenol removal studies. Box-Behnken-Design using quadratic model was chosen for three operating parameters (feed phenol concentration, pH and applied pressure) against two responses (phenol removal, flux). ANOVA shows that model is statistically valid with high coefficient of determination ($R^2$)value for flux (0.9897) and phenol removal (0.9302). The optimum conditions are obtained as pH 2, $46mg.l^{-1}$ (feed phenol concentration) and 483 kPa (applied pressure) with 92.3% phenol removal and $9.2l.m^{-2}.h^{-1}$ flux. Data validation with deviation of 4% confirms the suitability of model. Obtained results reveal that prepared composite membrane can efficiently separate phenol from aqueous solution.

• Journal of Ceramic Processing Research
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• v.21 no.6
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• pp.622-631
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• 2020

Fly ash is an industry by-product of thermal power factories that is broadly utilized in the concrete industry. This research shows a framework for evaluating the hydration heat, reaction amount, and strength progress of cement-fly ash binary composite. First, we conducted an experiment to study the isothermal hydration heat of fly ash composite paste with assorted fly ash contents and temperatures. According to the experimental outcomes of cumulative hydration heat, the coefficients of a kinetic reaction model of fly ash were determined. Furthermore, the reaction amount of fly ash was calculated using a fly ash reaction model. We discovered that the reaction of fly ash is considerably improved at elevated temperatures. The reaction amount of fly ash decreases with the growing content of fly ash. Second, in line with the reaction amount of fly ash and cement, we developed a straight-line equation for evaluating the strength progress of binary composite. The strength progress model applies to a number of water-to-binder ratios and fly ash substitution ratios. Summarily, the suggested hydration-heat-strength model is helpful for understanding the material style of fly ash concrete.