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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Ceramic Society
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Journal DOI :
The Korean Ceramic Society
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Volume & Issues
Volume 32, Issue 12 - Dec 1995
Volume 32, Issue 11 - Nov 1995
Volume 32, Issue 10 - Oct 1995
Volume 32, Issue 9 - Sep 1995
Volume 32, Issue 8 - Aug 1995
Volume 32, Issue 7 - Jul 1995
Volume 32, Issue 6 - Jun 1995
Volume 32, Issue 5 - May 1995
Volume 32, Issue 4 - Apr 1995
Volume 32, Issue 3 - Mar 1995
Volume 32, Issue 2 - Feb 1995
Volume 32, Issue 1 - Jan 1995
Volume 1, Issue 4 - 00 1995
Volume 1, Issue 3 - 00 1995
Volume 1, Issue 2 - 00 1995
Volume 1, Issue 1 - 00 1995
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Mechanical and Tribological Properties of Si-SiC-Graphite Composites
Journal of the Korean Ceramic Society, volume 32, issue 6, 1995, Pages 643~652
Si-SiC-graphite composites were developed by incorporating solid lubricant graphite into Si-SiC, in the light of improving tribological properties of Si-SiC ceramics. Si-SiC-graphite composites were fabricated by infilterating silicon melt into the mixture of α-SiC, carbon black and graphite powder at 1750℃ under 3 Torr. The particle size of graphite was in the range of 150 to 500㎛, and the loading content of graphite was 0, 20, 25, 30, 35 vol% in the mixture of α-SiC and carbon black. The mechanical and tribological properties of this composites were studied. The density, hardness, flexural strength, compressive strength and Young's modulus were decreased with increasing of graphite content. An additiion of solid-lubricant graphite up to 30 vol% has improved tribological properties of Si-SiC ceramics without considerable degradation of mechanical properties.
Directional Effect of Applied Pressure during the Sintering on the Microstructures and Fracture Toughness of Heat-treated Silicon Nitride Ceramics
Journal of the Korean Ceramic Society, volume 32, issue 6, 1995, Pages 653~658
Directional effect of applied pressure during sintering on the microstructure and fracture toughness of the heat-treated silicon nitride ceramics has been investigated. The specimens with a composition of 92Si3N4-8Y2O3(in wt%) were sintered at 172
by a hot press (HP ) and a hot isostatic press (HIP) and heat-treated for grain growth at 1800~20
. The fracture toughness of the HP samples increased with the grain size while the fracture toughness of the HIP treated samples remained the same even though the grain growth occurred. This discrepancy was explained by a bimodal grain size distribution and large aspect ratio of the HPed samples and a monomodal grain size distributjion and samll aspect ratio of the HIP treated samples.
Synthesis and Temperature Profile Analysis of ZrC by SHS Method
Journal of the Korean Ceramic Society, volume 32, issue 6, 1995, Pages 659~668
Zirconium carbide was prepared from the mixture of metal zirconium and carbon powders in argon atmosphere by Self-propagating High-temperature Synthesis (SHS) in order to obtain the best carbon source and dilution contents. The most exellent result was obtained in the case that active carbon was added as a starting material, 20~30 wt% dilution content. From thermal profile analysis an apparent activation energy of 118 KJ/mol was calculated. The maximum heating rate achieved during 15 wt% ZrC reaction by product dilution method was approximately 1.54
105 K/s. Coupling this value with the measured wave velocity of 1.026cm/s yielded a maximum thermal gradient fo
105 K/cm. Using the definition of t* and the measured wave velocity, the effective thermal diffusivity,
, was calculated to be 0.62
Deposition of Heavy Metal Oxide Glass Thin Films by R.F. Magnetron Sputtering
Journal of the Korean Ceramic Society, volume 32, issue 6, 1995, Pages 669~676
In this study, EO glass films were deposited by R.F. magnetron sputtering using EO glass target. The glass formation of the EO film was greatly dependent on the substrate temperature and the crystallization started at approximately 28
. As the temperature of the substrate or the oxygen content in the sputtering gas increased, UV/VIS/NIR absorption edge moved toward longer wavelength. A wave guiding phenomenon was observed from the prism-coupler experiment and a fluorescence of 1.06
originated from 4Fe3/2longrightarrow4I11/2 transition of Nd3+ was detected from the film containing Nd3+ ions.
Graphitization of Petroleum Cokes by Aluminum Catalyst
Journal of the Korean Ceramic Society, volume 32, issue 6, 1995, Pages 677~684
The effect of catalytic graphitization of petroleum cokes by the addition of aluminum were investigated. The degree of graphitization carbon body only fired at 230
was 0.5. But when the aluminum additive was added, the degree of graphitization was increased to 0.93. And Ts-effect was appeared as the catalytic effect. This effect was occurred by the formation-decomposition of aluminum carbide through the reaction of aluminum and cokes.
The Control of SiC/C Ratio for the Synthesis of SiC/C Functionally Gradient Materials
Journal of the Korean Ceramic Society, volume 32, issue 6, 1995, Pages 685~696
The most important techniques in the synthesis of SiC/C function gradient material (FGM) are to control the SiC/C ratio and to obtain the moderate deposition rate. For these, various gas systems and flow rates were attempted and evaluated. It turned out that the CH4＋SiCl4＋H2 system was suitable for the deposition of SiC-rich layers, the C3H8＋SiCl4＋Ar system for the deposition of carbon-rich layers, and the C3H8＋SiCl4＋H2＋Ar system was good to deposit the layers between them.
IR Transmittance and Surface Structure of Diamond Film Polished by Thermomechanical Method
Journal of the Korean Ceramic Society, volume 32, issue 6, 1995, Pages 697~702
The rough growth surfaces of diamond films fabricated by the hot filament CVD were polished using thermomechanical polishing method. And then, its application to the optical windows was discussed through the measurement of transmittance in the range of infrared radiation and analysis of surfaces structure. The results were compaerd with those of the films polished with conventional mechanicla polishing. The transmittance of the mechanically polished film reached 57~66% over the whole range from 500 to 4000 cm-1. But the transmittance of the film polished with thermomechanical polishing method was reduced below 35%. This decrease in transmittance was due to both the graphitization of diamond on the polished surface and the growth of
-SiC at diamond/Si interface during polishing. The residual Fe in hte thermomechanically polished surface was confirmed by SIMS analysis. This Fe played the role of the graphitization of near surface region of the diamond film.
A Study on the Synthesis of Organophilic Montmorillonite from Na-Montmorillonite and Octadecylenetrimethylammonium Ion and on itls Swelling Behavior
Journal of the Korean Ceramic Society, volume 32, issue 6, 1995, Pages 703~709
Octadecylenetrimethylammonium-montmorillonite as an organophilic montmorillonite intercalations complex was formed by cation exchange reaction between Na-montmorillonite and 9-octadecylenetrimethylammonium cation. After drying of this organophilic montmorillonite at
in high vacuum, the complexes were reacted with various swelling-solutions such as benzene, toluene, o-xylene, pyridine,
-picoline, 2-ethyl-pyridine, 2-vinyl-pyridine and styrene, and the corresponding basal spacing obtained were 43.9
A Study on the Si-SiC Composites Fabricated by Pressureless Powder Packing Forming Method
Journal of the Korean Ceramic Society, volume 32, issue 6, 1995, Pages 710~718
The new forming method, Pressureless Powder Packing Forming Method was applied to the manufacturing of reaction sintered SiC. After the experiments of vibratory powder packing and binder infiltration, the abrasive SiC powder of which mean size is 45
was selected to this forming method. Uniform green bodies with porosity of 45% and narrow pore size distribution could be formed by this new forming method. Also, complex or varied cross-sectional shapes could be easily manufactured through the silicone rubber mould used in this forming method. Maximum 15 wt% amorphous carbon was penetrated into green body by multi impregnation-carbonization cycles. And reaction-bonded SiC was manufactured by infiltration of SiC-carbon shaped bodies with liquid silicon.
The Effect of Adding Process of
on the Properties of
Dielectrics Prepared by Coprecipitation of
-Hydroxides in the Presence of
Journal of the Korean Ceramic Society, volume 32, issue 6, 1995, Pages 719~725
ZST powders were synthesized by coprecipitation of (Zr4+, Ti4+)-hydroxide in the presence of SnO2 particles. Zn(NO3)2 was used as a sintering additive, and according to the adding sequence, sintering and dielectric properties were investigated. Sintered densities of ZST prepared by adding Zn(NO3)2 before calcination were a little higher than those added after calcination, and dielectric properties of the specimen added by Zn(NO3)2 after calcination were better (sintered at 125
/2 h ; Q
r=41) than before calcination (Q
r=39.5). Through the observation of TEM, it was identified that the cause was due to the difference of the degree of Zn2+ diffusion into grains. With increasing sintering time from 2 to 8 hrs, grain size was doubled and dielectric properties were somewhat deteriorated.
Effects of Excess PbO and Ball-Milling on the Microstructure, Sintering Behavior and Mechanical Properties of PZT Ceramics
Journal of the Korean Ceramic Society, volume 32, issue 6, 1995, Pages 726~734
Pb(Zr0.53Ti0.47)O3 (PZT) ceramics having different microstructures were fabricated at low temperatures using calcined PZT powders with addition of excess PbO powder and/or ball milling. The effects of excess PbO and ball milling time on the microstructure, the sintering characteristic, and the mechanical properties of these ceramics were studied. Fine powders with average particle size of 0.38㎛ could be obtained by ball milling with 2.5 mm Ф zirconia balls for 120 hours. By the addition of 2mol% of excess PbO to these powders, it was possible to obtain well-densitified PZT ceramics at low sintering temperature of 980℃. Densification behavior of PZT was affected by the addition of excess PbO powder, while, grain growth was hardly affected by PbO addition. It was observed that Vicker's hardness decreased and fracture toughness increased with the increasing amount of PbO. At 1mol% excess PbO, it was shown that the minimum values of hardness and maximum fracture toughness were achieved. In addition, with increasing sintering time, the fracture toughness decreased and the hardness increased.
A Study on the Hydrothermal Synthesis of Clay Mineral (II) -Hydrothermal Synthesis of Clay Mineral from Anorthite in San.Chung District of Korea-
Journal of the Korean Ceramic Society, volume 32, issue 6, 1995, Pages 735~747
The synthesis of clay mineral through the hydrothermal reaction of the anorthite, which is distributed in San Chung-District of Korea and called as the ground rock for halloysite-kaolin, has been investigated. It was observed that this anorthite sample was easily converted into clay mineral with 0.5 wt% HCl solution at a temperature below 20
under a pressure about 15 atm. The conversion reaction was promoted by adding aluminum chloride under the condition concerned. Aluminum chloride was considered to supply the insufficient aluminum ion during the conversion reaction and to reprepare the acid solution-condition by adding the HCl-component as a by-product. According to the electron micrographs, it was confirmed that fine tubular or needle-shaped halloysite-kaolin minerals with the crystal length shorter than about 1.1
could be obtained by the hydrothermal reaction for 5 days under those conditions.
Pyroelectric Properties of
Journal of the Korean Ceramic Society, volume 32, issue 6, 1995, Pages 748~760
Pyroelectric properties, figure of merits, and the other properties of the Pb(Zn1/3Nb2/3)O3-Pb(Fe1/2Nb1/2)O3 system, as expected to have excellent pyroelectric properties in the operating temperature range of pyroelectric type infrared sensor, were investigated. In the Pb(Zn1/3Nb2/3)O3-Pb(Fe1/2Nb1/2)O3 system, suppression of the pyrochlore phase depended on sintering condition, as like sintering temperature, holding time, sintering atmosphere. The specimen, sintered by the same composition atmosphere powder at 105
for 1.5h, possessed the best physical property. It was found that the piezoelectric parameters were mainly depended on the amount of spontaneous polarization and then the 0.2PZN-0.8PFN showed the best pyro- and piezoelectric properties. In terms of the experimental method, two pyroelectric-testing methods, i.e. static and dynamic methods, had a same tendency. Also the result of pyroelectric testing by the static method indicated that the diffuse phase transitiion resulted in the temperature difference of phase transition between dielectric constant and pyroelectric coefficient.