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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Ceramic Society
Journal Basic Information
Journal DOI :
The Korean Ceramic Society
Editor in Chief :
Volume & Issues
Volume 27, Issue 8 - Aug 1990
Volume 27, Issue 7 - Jul 1990
Volume 27, Issue 6 - Jun 1990
Volume 27, Issue 5 - May 1990
Volume 27, Issue 4 - Apr 1990
Volume 27, Issue 3 - Mar 1990
Volume 27, Issue 2 - Feb 1990
Volume 27, Issue 1 - Jan 1990
Selecting the target year
A Study on Heavy Metal Adsorption of the Submicron HAP
Journal of the Korean Ceramic Society, volume 27, issue 1, 1990, Pages 1~6
Preparation and heavy metal ion adsorption of sumicron hydroxy apatite were studied in this experiment. Submicron HAP was synthesized with Ca(OH)2 solution and H3PO4.Ca(OH)2 solution was made from water-quenching of CaCO3 heated at 1, 00
and 20%-H3PO4 was dropped into this Ca(OH)2 solution heated at 8
. XRD pattern of prepared powder showed HAP crystal. The average particle size and sahpe of HAP were 0.25
and sphere type. As a adsorbent, 1.0g of the prepared HAP powder in 1 liter of artifical 5ppm heavy matal waste water was sufficient, and more effective at pH7-9.
Effect of MnO2 Addition on Sintering and PTCR Properties in Y2O3 doped BaTiO3 Semiconducting Ceramics
Journal of the Korean Ceramic Society, volume 27, issue 1, 1990, Pages 7~12
The influence of MnO2 on the sintering property and PTCR behavior of(Ba0.8Sr0.2)TiO2 has been investigated. And the densities, grain sizes and electrical resitivities of specimens were measured as a function of doping with Mn ion of varying concentration. The density and grain size of the sintered specimens were almost the same regardless of MnO2 addition up to 0.2mol% MnO2. But in the case of 0.25mol% MnO2 addition, abnormal grain growth was appeared. So the grain size distribution was wide and density decreased greatly. The room-temperature resistivity increased as Mn content increased and the temperature coefficient of resistivity was highest in the case of 0.15mol% MnO2 addition.
Preparation and Characteristics of Magnetite Ferrofluid
Journal of the Korean Ceramic Society, volume 27, issue 1, 1990, Pages 13~22
The magnetite ferrofluids of which solvents are water or kerosene have been prepared by making surfactant absorbed on the surface of the magnetite which have been synthesized by air oxidation of Fe(OH)2 at pH 11 and 75
, and their basic properties have been measured by XRD, SEM, DTA, TG, viscometer, magnetometer and B-H tracer. The results are as follows ; 1) The shape of magnetite prepared by air oxidation is found to be sphere-like shape and its particle size is smaller than 200A. 2) The maximum amount of sodium oleate adsorbed on the surface of magnetite is about 20% in the weight of the magnetite including the adsorbed sodium oleate. And when magnetite is well dispersed into solvent, R(the weight ratio of the added sodium oleate to Fe3O4) is 0.40-0.48. 3) The dispersion ratio, the viscosity and the magnetization of magnetite ferrofluid are constant regardless of the added amount of sodium oleate above R=0.40-0.48. 4) The magnetic hysteresis curves of magnetite ferrofluid show superparamagnetism-like behavior.
Prediction of Piezoelectric Coefficients of PZT-Polymer Composites by Finite Element Method
Journal of the Korean Ceramic Society, volume 27, issue 1, 1990, Pages 23~26
A model is developed based on the Finite Element Method (FEM) which provides a more accurate prediction of the hydrostatic piezoelectric coefficient of 1-3 or 3-1 PZT-Polymer composites than does the series/parallel model.
Single Crystal Growth of YBa2Cu3Ox by Flux Method
Journal of the Korean Ceramic Society, volume 27, issue 1, 1990, Pages 27~34
Single crystals of YBa2Cu3Ox superconductor were grown by means of the flux method. The effectof starting material, cooling rate, melting time, and melting temperjature were evaluated as influencing paraemters. The larger single crystals of YBa2Cu3Ox were obtained with Y2BaCuOy powder as a starting material than with YBa2Cu3Ox powder. The optimum range of synthetic condition for single crystal growth was as follows ; 2-5
/hour of cooling rate, 2-5 hour of melting time and melting temperature at 106
. The obtained size of single crystal was 2mm in average and the largest one was 5mm in maximum.
A Study on Pyroelectric Characteristics of PZT/Polymer Composite Material
Journal of the Korean Ceramic Society, volume 27, issue 1, 1990, Pages 35~42
In the present investigation, ceramic PZT and Polymer were prepared. The former is Pb[(Sn1/2Sb1/2)0.1 Ti0.27Zr0.63]O3 including Pb(Sn1/2Sb1/2)O3 with good pyroelectric effect, and the latter PVA(Poly Vinyl Alcohol) with good plasticity. Then, they were fabricated to be flat by using 0-3 connectivity which is rather easily fabricated and capable of making thin film, extending surface area among the connectivities. Such were applied to the sample as variation of intensity of poling field, poling temperature, volume fraction between ceramic and polymer. Then dielectric constant, pyroelectric current, pyroelectric coefficient and the figure of merit were measured. And then their effects on pyroelectric characteristics were observed.
Y-Ba-Cu-O Single Crystals Growth by Skull Method
Journal of the Korean Ceramic Society, volume 27, issue 1, 1990, Pages 43~47
An attempt was made to grow Y-Ba-Cu-O single crystals by skull method(cold crucible process). Grown YBa2Cu3O7-x(YBC) single crystals were obtained from the upper part of the YBC solid mixture. There were plate-like YBC single crystals aligned with solidified flux along the crystal growth direction. Single crystal size was (5
0.2㎣) and was grown to a-b plane of YBC crystal structure which can flow super currents. Optical microscope and X-ray diffraction were employed characterize these microstructure and YBC single crystals.
Growth of Superconductor YBa2Cu3O7-x Single Crystal by Flux Method
Journal of the Korean Ceramic Society, volume 27, issue 1, 1990, Pages 48~54
YBa2Cu3O7-x(=YBCO) single crystals were grown by flux method and the growing process of crystals was investigated. YBCO and 3BaO-7CuO composition powders were mixed by the ratio of 25 : 75(wt%), and the mixtures were melted at 105
in a electric furnace with no temperature-gradient. Then the melt was cooled at a rate 2-1
/h in the above furnace. YBCO single crystal plate with average size of
0.1㎣ were obtained in the cavities between crucible and solidified ingot, and the single crystals were oriented to <001> direction. The ingots of flux parts were analyzed by XRD and EDS for the purpose of presuming the growing process of the crystals. It was assumed that the divorced eutectic reaction, by which YBCO crystals were grown first and then BaCuO2 and CuO crystals, occured in the case of cooling rate faster than 2
/h. When the cooling rate was 2
/h, it was assumed that quasi-equilibrium eutectic reaction occured, so that YBCO, BaCuO2 and CuO crystals were grown at the same time.
A Study on the Ceria Stabilized Tetragonal Zirconia Polycrystals(Ce-TZP)(III) : Effect of Al2O3 Addition on the Mechanical Properities and Microstructures of Ce-TZP
Journal of the Korean Ceramic Society, volume 27, issue 1, 1990, Pages 55~61
Effect of Al2O3 addition on the mechanical properties and microstructure of Ce-TZP were studied. 12, 14, 16Ce-TZP containing 0-40wt% Al2O3 were prepared by sintering at 155
for 2h. in air. Density, linear shrinkage, bending strength, Vickers hardness, microstructuer and the amount of stress induced phase transformation were examined. Vickers hardness increased linearly with increasing amounts of Al2O3. The amount of transformation and fracture toughness decreased linearly with increasing amount of Al2O3. Linear shrinkage and relative density decreased with increasing Al2O3 content in all composition of Ce-TZP. Grain growth of Ce-TZP was inhibited by Al2O3 dispersion and fracture mode of Ce-TZP/Al2O3 composites transformed from intergranular to transgranular fracture as the amount of Al2O3 increased. TEM observation revealed that Al2O3 particles were located mainly at grain boundaries of ZrO2.
Preparation of La-modified PbTiO3 Ceramics on Coprecipitation and Salt Decomposition Method
Journal of the Korean Ceramic Society, volume 27, issue 1, 1990, Pages 62~66
La-modified PbTiO3 Powders and ceramics were prepared by coprecipitation and salt decomposition method. In this process, fine and homogeneous single phase of La-modified PbTiO3 was synthesized at lower temperature than oxide mixing method. And these powders contributed to lowering calcination temperature and rising sintering properties. The properties of these powders and the change of properties with themperature and the effect of powder properties on sintering were investigated.
Characterization of Glasses by Ion-Exchange (III) : Behavior of Optical Properties
Journal of the Korean Ceramic Society, volume 27, issue 1, 1990, Pages 67~73
The behavior of optical properties of ion exchanged glasses was investigated inthis study. The used glasses were soda-lime-silica glasses that were produced by float process. The coloring effect by Ag colloids is measrued by spectral transmittance, color coordinates, dominant wavelength and excitation purity resulting from silver ions exchange of glasses immersed into the mixed molten salt with AgNO3. Ion exchange coloring of glasses made it possible to obtain glasses with a range from yellow to brown, and transmittance was decreased with increasing the amount of Ag colloids which reduced from Ag+ions. Also, obtain from yellow to reddish brown with increasing purity by reheating treatment in air for ion exchanged glasses. The size of Ag colloids are 0.02~0.1
with ion exchange conditions.
Study on the Preparation of the Piezoelectric Composite Materials in PZT Ceramics-Polymers by Extrusion Method and its Properties
Journal of the Korean Ceramic Society, volume 27, issue 1, 1990, Pages 74~78
In this study, to develope the ultrasonic transducer element, the extrusion method which is the processing technique of the piezoelectric composite materials is introduced, the connectivity of the piezoelectric composite materials is the 1-3 type, and we study the properties of the materials. The electromechanical coupling factor(kt) of the materials is above 0.6, the resonance property(fr) is the thickness mode in the frequency range of 0.5 to 2 [MHz] and the acoustic impedance(Zac) is about 5 to 7 [Maryl]. From these results, it is known that the piezoelectric composite materials manufactured byt he extrusion method will be able to develope the ultrasonic transducer elements.
A Study on the SiO2Sensing Layer Used in ISFET
Journal of the Korean Ceramic Society, volume 27, issue 1, 1990, Pages 79~85
A study on the oxidation of SiO2 sensing layer was done at 950, 1000, 105
under dry O2 atmosphere. The rate determining step around the oxide layer thickness, 1000
was different with the oxidation temperature, as follows ; ⅰ) linear growth at 95
and ⅱ) parabolic growth at 100
. The flatness of SiO2 film was observed within
1% and surface state charge density was reduced by annealing in N2 atmosphere. Finally, pH sensitivity of SiO2 film, in the range of pH 3-9, was 20mV/pH.
The Effects of Catalyst on the Hydrolysis and Polymerization of TEOS
Journal of the Korean Ceramic Society, volume 27, issue 1, 1990, Pages 86~90
The shape and characteristics of polymers in hydrolzed and polymerized sol were affected by the types of catalysts. In our research, the contents of water and catalysts were constant and the types of catalyst were varied. In the case of acid catalysts, polymers in sol were linear and spinnable. The shapes of polymer were affected by the types of anions in acid catalysts. In the case of catalyst having anions, F, Cl, in the same period, the effects were similar. But in the case of base catalysts polymers were rigid rod like and not spinnable.
Correlation of the Green Microstructure of ZrO2 with the Colloid/Interface Variables
Journal of the Korean Ceramic Society, volume 27, issue 1, 1990, Pages 91~101
The green microstructure and sintering behavior of ZrO2 were analyzed in terms of kinetic stability (measured by the stability ratio ; W) and interfacial characteristics of colloidal suspension. Green density and the most frequent pore radius(MFPR) of green body were directly correlated with the stability ratio. These observations were explained using a concept of the critical stability ratio(Wc) and the potential energy of two interacting particles in colloidal suspension. Analysis of the data also indicates that the potential energy barrier between two interacting colloid particles should be higher than its critical value for a fabrication of ZrO2 green body with dense and uniform microstructure. Besides, we have successfully applied a concept of the donoracceptor interaction to increase the kinetic stability of ZrO2 slip and density of green body.
Fracture Behavior and Mechanical properties of WC-Co Subjected to Thermal Shock
Journal of the Korean Ceramic Society, volume 27, issue 1, 1990, Pages 102~108
WC-Co composites are widely used as cutting or drilling tools because of their high hardness, strength, and fracture toughness. The working temperature is, however, generally in the range of 300-
so thermal shock fracture of WC-Co can occur. In this study, the strength, fracture toughness and fracture surface of 16wt% Co bonded tungsten carbide composites before and after thermal shock were observed.
The Characteristics of Water Based Ferrofluid of Magnetite Prepared by Air Oxidation
Journal of the Korean Ceramic Society, volume 27, issue 1, 1990, Pages 109~117
Magnetite for Water-based ferrofluid was synthesized by air oxidation of aqueous suspension in the pH range 7-12 at
. The optimum condition of magneite formation was delineated by examining various physicochemcial properties such as Fe2+ content, phase characteristics, MHC and
max. The point of zero charge of iron oxide powders obtained at various pH conditions were correlated with the oxidation state of Fe in the iron oxide. The magnetite powder prepared at pH 9 ws dispersed using sodium oleate and sodium dodecylbenzenesulfonate (SDBS) as dispersants, and the dispersion characteristics of the magnetite ferrofluid were examined by means of the fraction of solid dispersed, zeta potential data and FT-IR spectrum. A simple calculation on the potential energy of two interacting magnetite particles showed that the dispersion stability was directly correlated with height of the potential energy barrier or the shape of zeta potential.
Systhesis and Sintering Characterization of TiC by Self-Propagating High Temperature Synthesis
Journal of the Korean Ceramic Society, volume 27, issue 1, 1990, Pages 118~126
Titanium Cabride powders were prepared by the self-propagating high temperature synthesismethod in air from the mixture of metal titanium powder and carbon powder. The result are as follows : 1. The conversion effciency of higher than 95% can be obtained and the lattice constant value of the product was 4.322
. 2. The combustion mode, velocity and temperature of combustion wave was photographed using high-speed camera, and showed steady-state, velocity of 15.414mm/sec at 250
. 3. The relative density and MOR strength of TiC sintered at 180
for 90 minutes by hot-pressing under the pressure of 200kg/
were 95% and 395MPa, respectively.
Characteristics of the (Ba1-xPbx)TiO3 Powders Prepared by Various Synthesis Method
Journal of the Korean Ceramic Society, volume 27, issue 1, 1990, Pages 127~135
Characteristics of the sol-gel derived (Ba1-xPbx)TiO3 powders are compared with those of powders prepared by the calcining ofmixed oxides method (CMO) and molten salt synthesis method(MSS). The sol-gel derived powder has a higher surface area (50
/g) than those of CMO(3.8
/g) and MSS(11.5
/g) derived powders. In the sol-gel method, the (Ba1-xPbx)TiO3 was synthesized at
for 1hr, indicating that this method has a crystalline temperature 20
lowr than those of the CMO and MSS methods.
Formation and Characterization of Silicon Carbide Whiskers by Acheson Method
Journal of the Korean Ceramic Society, volume 27, issue 1, 1990, Pages 136~146
Whiskers of SiC were grown from the mixture of silica and graphite powders by Acheson method(direct heating method). The structrua, morphological and chemical characterizations have been performed by X-ray diffractometer(XRD), transmission electron microscopy(TEM), optical microscopy(OM), scanning electron microscopy(SEM), X-ray photoelectron spectroscopy(XPS) and energy dispersive spectrometer(EDS). The growth mechanism of SiC whiskers is also discussed.