Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korean Ceramic Society
Journal Basic Information
Journal DOI :
The Korean Ceramic Society
Editor in Chief :
Volume & Issues
Volume 36, Issue 12 - Dec 1999
Volume 36, Issue 11 - Nov 1999
Volume 36, Issue 10 - Oct 1999
Volume 36, Issue 9 - Sep 1999
Volume 36, Issue 8 - Aug 1999
Volume 36, Issue 7 - Jul 1999
Volume 36, Issue 6 - Jun 1999
Volume 36, Issue 5 - May 1999
Volume 36, Issue 4 - Apr 1999
Volume 36, Issue 3 - Mar 1999
Volume 36, Issue 2 - Feb 1999
Volume 36, Issue 1 - Jan 1999
Volume 5, Issue 4 - 00 1999
Volume 5, Issue 3 - 00 1999
Volume 5, Issue 2 - 00 1999
Volume 5, Issue 1 - 00 1999
Selecting the target year
Fabrication and Electrical Characteristics of SrZr
Journal of the Korean Ceramic Society, volume 36, issue 7, 1999, Pages 679~684
Specimens of SrZr0.95Ga0.05O3-
were fabricated by a solid-state reaction method and subsequent sintering at 150
The microstructures and electrical characteristics of the specimens were studied. Only BaZr0.95Ga0.05O3-
showed dense microstructure and had typical impedance spectra at various temperature. Its electrical conductivity by impedance analysis was 2.7
-1.cm-1 at 90
in air. The BaZr0.95Ga0.05O3-
exhibited lower grain rsistance in wet atmosphere than in dry atmosphere and the reduction of resistance is due to the proton conduction.
Properties of the Modified Belite Cement with Slag
Journal of the Korean Ceramic Society, volume 36, issue 7, 1999, Pages 685~690
Modified belite cement clinker containing
'-C2S and C4A3 were syntehsized form the mixture of raw materials.
'-C2S was stabilized at room temperature by adding borax. Properties of the clinker were charaterized with a XRD, SEM, TEM The additive effects of slag on the hydration properties were also estimated by measurement of compressive strength fluidity and heat evolution. The experimental results exhibited that the addition of slag to the belite cement improves the fluidity and early compressive strength due to the formation of ettringite and C-S-H. The compressive strengths of the mortar with 20% slag after 7, 90 days hydration were 212, 355 kgf/cm2 respectively.
Surface Modification of Mica Using TiO
prepared by Alkoxide Hydrolysis Method
Journal of the Korean Ceramic Society, volume 36, issue 7, 1999, Pages 691~697
TiO2 powder was adsorbed on the surface of mica using the heterocoagulation method in water TiO2 powder was prepared from hydrolysis of titanium-iso propoxide in a mixed solvent of anhydrous ethanol and water. When the molar ratio of water to titanium iso-propoxide was 0.25 monodispersed spherical TiO2 particles were obtained. The prepared TiO2 powder showed anatase phase after heat treatment at 50
for 2 h and then transformed to rutile phase after heat treatment at 100
for 2h. The iso-electric points of TiO2 and Mica were pH 3.9 and pH 3.25 respectively which were measured by the Z-potential analysis in water base. The maximum Z-potential difference between two powders was observed in the range of pH 3.6~3.7 TiO2 powder was adsorbed on the surface of mica by heterocoagulation method in pH 3.6~3,7 The properties of prepared TiO2 powder was haracterized by TG-DTA, XRD and SEM The morphology and thermal properties of TiO2-adsorbed mica were examined.
Wet Chemical Preparation of Li-rich LiMn
Spinel by Oxalate Precipitation
Journal of the Korean Ceramic Society, volume 36, issue 7, 1999, Pages 698~704
Li rich Li1+xMn2-xO4(x=0.07) spinel powders were prepared by an oxalate precipitation of wet chemical methods at temperature lower than
. The FTIR results showed that the powders prepared at
had high degree of crystal quality comparing with the spinel powders prepared by solid state reaction at 75
which was the lowest synthesis temperature of the solid state reaction method. The particle size of powders prepared by the oxalate precipitation at
was smaller than 0.2
and the specific surface area was 11.01 m2/g A heat treatment over 90
formed second phase in the precipitates. It was shown that there were phase transitions at temperatures. T1,T2 and T2. The transitions involved weight loss and gain during heating and cooling. The low temperature synthesis below
avoided the second phase formation and the prepared powders showed improved compositional and physical properties for secondary lithium battery applications.
Investigation of Slury Properties for Aqueous Casting of Nano-Size Barium Titanate
Journal of the Korean Ceramic Society, volume 36, issue 7, 1999, Pages 705~710
Stability and chemical durability for aqueous casting of BaTiO3 slurry with polycarylic acid(PAA) were studied. PAA was well chemisorbed on surface of BaTiO3 powder at neutral pH but did not chemically adsorbed at low pH. The amount of Ba dissolution in aqueous BaTiO3 slurry was abruptly increased at strong acid pH2 and also at high amount of PAA. Protection of Ba dissolution and stability of slurry could be obtained through the optimization of slurry conditions such as pH amount of surfactant and solid content.
Biaxial Fracture Behavior of Alumina Ceramics ; Thickness Effect on Ball-on-3-ball Test
Journal of the Korean Ceramic Society, volume 36, issue 7, 1999, Pages 711~717
Biaxial fracture behavior of alumina specimens with the diameter of 20mm and four kinds of thickness of 1.9, 2.3, 2.6 and 2.8mm was studied by the ball-on-3-ball test and the fracture results were analyzed by he analysis of variance (ANOCA), The strength measured with the down speed prescribed in ASTM showed that the measured strength was not dependent on the thickness of the specimens. Equivalent radius and crack-braching number were observed to increase lineraly with the thickness of the specimens. The jog direction was observed to study the effect of grinding direction on surface flaws. It is though that the surface finishing with #600 grit diamond wheel did not affect the surface flaws of the specimens.
Sintering Behavior of Bimodal Size-Distributed Alumina Powder Mixtures
Journal of the Korean Ceramic Society, volume 36, issue 7, 1999, Pages 718~724
Densification and grain growth behavior of bimodal size distributed alumina powder mixtures were investigated as a function of amount of coarse alumina powder. The specimens which contained coarse alumina powder for 60to 80wt% showed the highest green density. The amount of shrinkage of sintered specimen lineraly decreased with the increase of coarse alumina powder up to the content that showed the highest green density and then further addition of coarse alumina powder led to drastic decrease of shrinkage of specimen. Especially crack-like void were concurrently revealed in the sintered body with addition of coarse alumina powder above 60wt% When the sintering temperature increased up to 1650
the amount of shrinkage of specimen linearly decreased and the grain growth were also retarded with increase of coarse lauminia powder.
A Study on the Stabilization/ Solidification Process Using Blast Furnace Slag
Journal of the Korean Ceramic Society, volume 36, issue 7, 1999, Pages 725~733
It is a fundamental experiment to use blast-furnace slag in solidification/stabilization process. The compressive strength and leaching test of Pb and Cr doped samples were evaluated and the effects of heavy-metal ions on the hydration of slag was investigated. Sodium silicates(5wt%) was added as alkali-activator and the effects of replacing a part of slag with flyash or gypsum was also discussed. Pb ion was solidified by encapsulation of matrix. In of slag
gypsum binder microstructure was densified by accelerating to form AFt/AFm phase and compressive strength was improved resulting in reducing leaching amount of Pb ion. Cr ion was solidified by substituting with Al ion in aluminate product. Slag+fly ash binder improved compressive strength and decreased leaching amount of Cr ion.
Microstructure and Mechanical Properties of
Journal of the Korean Ceramic Society, volume 36, issue 7, 1999, Pages 734~741
Al2O3/t-ZrO2 particulate composites were prepared by sintering at 150
for 2h in air and microstructure and mechanical properties of the composites were investigated. Although most ZrO2 particles existed at Al2O3 grain boundaries a few ZrO2 particles within Al2O3 grains. Al2O3 grain growth was depressed due to the pinning effect by ZrO2 particles. During sintering coarsening of intergranular ZrO2 particles occurred as a results of the elimination of ZrO2 intraagglomerate grain boundaries and the coalescence of dragged ZrO2 particles by migrating Al2O3 grain boundries. Changes in mechanical properties of Al2O3 composites were dependant on microstructure of Al2O3 matrix and on size and structure of dispersed ZrO2
Synthesis of Nanosized TiO
Powder by Chemical Vapor Condensation Process(1)
Journal of the Korean Ceramic Society, volume 36, issue 7, 1999, Pages 742~750
Nanosized TiO2 powders were synthesized using the chemical vapor conduensation (CVC) process with various precursor feeding rates (0.37 and 0.752 ml/min) and oxygen flow rates(1-2slm) conditions and powder characteristics were investigated in terms of formation of nanosized powder varying with the above processing conditions. For this study the main thermodynamic and fluid dynamic factors -supersaturation ratio collision frequency and residence time-were theoretically established and compared to the characteristics of formed TiO2 powder. The loosely combined anatase phase powders (including less than 3%of rutile phase) having 20-30nm crystallite size were obtained at overall conditions. The particle size and th degree of agglomeration for a precursor flow rate of 0.376 ml/min turn out to be smaller than for a flow rate of 0.742ml/min. And the decreasing of particles size and particle size distribution were observed with increasing oxygen flow rate as the residence time and collision frequency were reduced by increasing oxygen flow rate,. It appears that further scrutiny is needed to elucidate the influence of the individual thermodynamic and kinetic parameters
Effects of Ultrasonic Energy on Mn-Zn Ferrite Powder Behavior
Journal of the Korean Ceramic Society, volume 36, issue 7, 1999, Pages 751~755
Effect of ultrasonic-wave irradiation on the Mn-Zn ferrite powder suspension prepared by solid-state reaction and alcoholic dehydration methods was investigated. Size distribution and morphology of the powders prepared at different temperature were examined as a function of irradiation time. It was observed that the powders were reduced in size by ultrasonic energy through distinct routes.
Preparation of Activated Carbon Assembly By Using Glass Fabrics and Its SO
Journal of the Korean Ceramic Society, volume 36, issue 7, 1999, Pages 756~761
Inexpensive Ctivated carbon assembly (ACA) was prepared with glass fabrics coated by 10wt% 25wt% 50wt% phenoloic resin solution followed by activation at
under N2 atmosphere and subsequent surface modification with N2, NH3 CO2 gas respectively. The conversion chemistry of resin to carbon was analyzed by using FT-IR. TGA, SEM, XPS. and the SO2 adsorption characteristics of the ACA were compared to that of commerical activated carbon fabrics(ACF). The ACA modified by NH3 showed the best SO2 adsorption behavior due to the presence of basci functional groups such as amine on the surface confirmed by XPS. The ACA modified by NH3 displayed relatively high adsorption capacity of 116.5mg/g carbon which is corresponding to 75% adsorption of the commercial ACF(153.4mg/g) treated with the same method
Structural Studies of
) Ceramics using High Resolution Transmission Electron Microscopy
Journal of the Korean Ceramic Society, volume 36, issue 7, 1999, Pages 762~766
The crystal structure of A2+(Mg1/3Nb2/3)O3,(A2+=Sr2+ and Ca2+)ceramics was studied usig X-ray diffraction (XRD) and high resolution transmission electrion microscopy(HRTEM). Ba(Mg1/3Nb2/3)O3 (SMN) has the 1:2 ordered monoclinic structure which has the anti-phase tilt of octahedra. The type of tilting in SMN was considered to be a
c- or aac
Ca(Mg1/3Nb2/3)O3 (CMN) also has the 1:2 ordered monoclinic structure which was distorted by the anti-phase tilt or in-phsae tilt of octahedra. A unit cell containing both the in-phase tilt axis and anti-phase tilt axis was not observed in the CMN. Therefore CMN has the mixed phase consisting of the 1:2 ordered monoclinic phase with anti-phase tilt of octahedra and the one with in -phase tilt of ocatahedra,. The anti-parallel shift of cation was also observed in the CMN.
Effect of B
Addition on the Sintering Behavior Dielectric and Ferroelectric Properties of
Journal of the Korean Ceramic Society, volume 36, issue 7, 1999, Pages 767~772
The effect of B2O3 addition on the sintering behavior dielectric and ferroelectric properties of Ba0.7Sr0.3TiO3 ceramics were investigated. The sample with 0.5wt% B2O3 was sintered under 115
. The dielectric and ferroelectric properties of BST with 0.5wt% B2O3 was as good as BST without B2O3 sintered at 135
and its dielectric loss was even better When B2O3 was added over 1.0wt% the overdoped B2O3 remained in the specimens and formed a second phase which degraded the sintering behaivor dielectric properties of BST.
Fabrication of Complex-shaped mullite Ceamics by Gelcasting
Journal of the Korean Ceramic Society, volume 36, issue 7, 1999, Pages 773~781
A new technique to fabricate complex-shaped mullite has been developed through gelcasting without organic binder. The suspension of a commercial mullite powder and boehmite-SiO2 sol as binder was elecrtrosterically stabilized. Ammonium polymetharylyate was employed as a dispersant for the electrosteric stabilization. Complex-shaped bodies were made through casting and gelation at room temperature. The green bodies were dried at a temperature of 30
and relative humidity of 98% without crack development. The dried bodies were then pressureless-sintered at 1650
for 2 h to get a relative density of 98% The Vickers hardness and 4-point flexural strength of sintered parts were 11.0 GPa and 150MPa respectively which are similar to those of commercially available sintered mullite.