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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 25, Issue 6 - Jun 1988
Volume 25, Issue 5 - May 1988
Volume 25, Issue 4 - Apr 1988
Volume 25, Issue 3 - Mar 1988
Volume 25, Issue 2 - Feb 1988
Volume 25, Issue 1 - Jan 1988
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Preparation of Monosized Titanium Dioxide Powder from TEOT
안영필 ; 최석홍 ;
Journal of the Korean Ceramic Society, volume 25, issue 5, 1988, Pages 50~50
The controlled Ti(CO2H5)4 hydrolysis reactions for the synthesis of Spherical Monodispersed Titania powders are described. Increasing the concentration of TEOT and the molar ratio of water to TEOT in alcohol solution decrease the reaction time and the particle size. The reaction time is delalyed by increasing the chain length and the number of carbon branches of alcohol as a solvent. The prepared powders with an average diameter of 0.8μ and the spherical monodispersed transfer to Rutile phase at 550℃.
A Study on the Development of Polycrystalline Alumina Fibers in the Non-aqueous System
Journal of the Korean Ceramic Society, volume 25, issue 5, 1988, Pages 425~430
In this study, aluminum sec-butoxide, aluminum iso-propoxide were mixed with alcohol such as, secbutanol, iso-propanol. And then Acetyl Acetone, water were added to make Acetyl bond and OH bond. After that, Polymeric alumina sol was synthesized from catalysis reaction with strong acid typically HCl. These alumina soil was dried at 8
to have a optmum viscosty for spinning, spinned at spinner, and then sintered to make polycrystalline alumina fiber.
Properties of Li2O-Al2O3-SiO2 Glass Ceramic System(I)
Journal of the Korean Ceramic Society, volume 25, issue 5, 1988, Pages 431~436
The properties of scid-resistance to boiling HCl, thermal expansion coefficient and softening temperature of mother glass and glass-ceramic of LAS systems were investigated at the contents of SiO2 varing from 57 to 67wt%. The nucleation and growth of crystalline phase of LAS compositions were carried out at 50
. The crystalline phase jconsists of lithium alumino silicate, lithum meta silicate, lithium disilicate,
-quartz. Lithium alumino silicate(virgilite) is the major crystalline phase in the glass ceramics. The degree of acid resistant property was increased in proportion with the silica content for both glass and ceramics. Glass-ceramic gives lower acid-resistance and thermal expansion coefficient while softening temperature shows higher for glass-ceramic than for mother glass.
A Study on Binary System of Calcium Phosphate-Kaolin, -Quartz, -Feldspar and Limestone
Journal of the Korean Ceramic Society, volume 25, issue 5, 1988, Pages 437~442
We have suffered number of problems in supplying bone ash for bone china bodies as raw materals, because of its impurity and quantity. To reduce these problems, we have synthesized tricalcium phosphate that was reacted by H2PO4 and CaCO3 ; 3Ca(OH)2＋2H3PO4longrightarrowCa3(PO4)2＋6H2O. Therefore, we have studied solid reactions of synthesized tricalcium phosphate withkaoline, limestone, feldspar and silica, respectively.
Colored Cubic Zirconia(CCZ) Single Crystal Growth by Skull Method
Journal of the Korean Ceramic Society, volume 25, issue 5, 1988, Pages 443~448
Colored Cubic Zircona(CCZ) single crystals were grown by the skull melting method. The grown crystals were doped with up to 0.1wt% transition (Cu, Ni, Co, Ti, Fe, Mo, Cr, V, Mn) metal ions on ZrO2-Y2O3(9.5~10mol%) and their Optical transmission spectra(λ=300~800nm)data were obtained. Various colors were pronounced due to dopant effects in the grown Crystals.
Effects of Salts on the Hydration of
-Calcium Sulfate Hemihydrate
Journal of the Korean Ceramic Society, volume 25, issue 5, 1988, Pages 449~454
The effects of salts which was used as a catalysis in formation of
-calciumusulfate hemihydrate from dicalcium sulfate hydrate were investigated on the hydration of
-calciumsulfate hemihydrate. The hydration of
-calciumsulfate hemihydrate was studied by the measurements of crystalline water, heat evolution. Also the hydrates were analyzed by XRD, DSC and SEM. The promotive effect each salts on the hydration was as follows: NaCl>NH4Cl>NaNO3>NH4NO3, and the hydration rate was accelerated with concentration of salts. The effect of Al2(SO4)3 and potassium sodium tartrate on the hydration was slmilar to water, whereas sodium succinate and gelatin retarded the hydration in comparision with water. These salts affected the hydration time but total heat evoution was similar.
Properties of Reinforced Concrete Used for Disposal Container of Low-and Intermediate-level Radioactive Wastes
Journal of the Korean Ceramic Society, volume 25, issue 5, 1988, Pages 455~464
Concrete used for radwaste container should have excellent properties such as mechanical strength, water-tightness, durability, etc. In order to improve such properties of ordinary portland cement concrete, superplasticizer, steel fiber, and/or epoxy resin were added to ordinary portland cement concrete respectively. Various concrete specimens were prepared and the physical properties of each concrete specimen were tested. From the experimental results, the properties of steel fiber and epoxy resin reinforced concrete were proved to be better qualified than others for low-and intermediate-level radwaste container.
Properties of Alumina Powder Prepared by Precipitation Method (III) : Sintering Behavior
Journal of the Korean Ceramic Society, volume 25, issue 5, 1988, Pages 465~472
Alpha alumina powder with fine particle size and narrow particle size distribution was prepared by precipitation method using Al2(SO4)3.18H2O as a starting material. The alpha alumina powder was prepared by calcining aluminum hydroxide which was formed under various pH values. The sinterabilityof alpha alumina powder and the effect of MgO on the sinterability of alpha alumina powder were investigated. The sinterability of alpha alumina powder was the order of pH=10≒pH11>pH=7≒pH9, and alpha alumina obtained from boehmite which was prepared by precipitation method reached to 97.5% of theoretcal density by the pressureless sintering. The effect of MgO on volume shrinkage of alumina was very slight in the initial sintering stage but remarkable in the final sintering stage. It was also found that MgO controlled effectively the grain growth of alumina.
A Study on Synthesis of High Purity
-SiC Fine Particle from Ethylsilicate(I) -Reaction Conditon, Yeild and Properties of
Journal of the Korean Ceramic Society, volume 25, issue 5, 1988, Pages 473~478
In order to obtain the high purity
-SiC powder that possesses the excellent sinterability and is close to the spherical shape, the carbon black was mixed into the composition of Si(OC2H5)4-H2O-NH3-C2H5OH which the monodispersed spherical fine particles is formed the hydrolysis of Ethylsilicate and the mixture was carbonized under an argon atmosphere. Particle shpae, size and the yield of
-SiC powder were investigated according to the molar ratio of carbon/alkoxide and variations of reaction temperature and reaction time. The results of this study are as follow ; 1) The yield of
-SiC gained from the reaction for one hour at 150
almost got near 100% and the particle size of
-SiC from the reaction for 15 hrs at 150
on the average and close to the spherical shape agglomerate state. 2) When the molar ratio carbon/alkoxide is over 3.1 and the reaction occurs at 145
for 5hrs, the carbon content has not an effect on the kind of crystal of product.
Silica Glass Preparation by The Sol-Gel Process and The Effects of Glycerol as a DCCA
Journal of the Korean Ceramic Society, volume 25, issue 5, 1988, Pages 479~487
In this study we studied the function of Glycerol as a DCCA(Drying Control Chemical Additives) in the preparation of silica bulk glas through Sol-Gel method. We used TEOS(Tetra Ethyl Ortho Silicate) and maintained the mixing ratio of TEOS : H2O : EtOH : HCI as 1 : 4 : 4 : 0.0007(mol) and varied glycerol input quantity from 0.1vol% considering the ethnaol input quantity as 100vol%. We investigated the changes from Sol-Gel Synthetic solutions to the glass using DT-TG, FT-IR and other instruments. The results obtained from this experiment showed that the dried gels made from the synthetic solutions containing 0.1-1.0vol% of glycerol were easily heat-treated up to 85
so that transparant bulk silica glass was prepared.
Comparisons on Dielectric and Peizoelectric Proeprties of Rhombohedral, Tetragonal and Morphotropic Phase Boundary in Pb(Ni1/3Nb2/3)O3-PbTiO3-PbZrO3 System with MnO2 Addition
Journal of the Korean Ceramic Society, volume 25, issue 5, 1988, Pages 488~494
Effects of MnO2 addition on themicrostructure, dielectric and piezoelectric properties of Rhombohedral, Tetragonal and Morphotropic phase boundary(MPB) in Pb(Ni1/3Nb2/3)O3-PbTiO3-PbZrO3 system were investigated and respectively the amount of MnO2 addition was 0, 0.2, 0.5, 1.0, 3.0wt%. In the tetragonal region, compared with the Rhombohedral and Morpotropic phase boundary, Mechanical quality factor(Qm), Curie temperature(Tc) and Dissipation factor were promoted by addition of MnO2. According to the results of the microstructure, dielectric and piezoelectric properties, the solid solution range of MnO2 addition in this system was 0.2-0.5wt%.
Growth of Sapphire Crystals by Verneuil Method
Journal of the Korean Ceramic Society, volume 25, issue 5, 1988, Pages 495~501
Verneuil method uses oxyhydrogen flame for its heat source. This method was used to grow corundum monocrystals. Parametersof this method are feeding rate, gas pressure, lowering rate and growth axis. These parameters were examined. Crystals's qualities and shapes are affected by these parameters. Crystals having good qualities and shape were grown under the conditions that feeding rate, 0.2∼0.5g/min, lowering rate, 10∼20mm/hr ; gas pressure, 3∼4psi ; growth axis was shifted 60 degrees from c axis.
Phase Transformation of
Journal of the Korean Ceramic Society, volume 25, issue 5, 1988, Pages 502~508
phase transformation of
-Si3N4 whisker and related microstructural changes have been investigated. When only
-Si3N4 whisker was heat treated in the range 1650~175
phase transformation occured. In this case, it eas suggested that the oxygen content in
-Si3N4 whisker affected the transformation behavior. Although
-Si3N4 whisker with Si was heat treated under the same condition, however, the variation of
- fraction had a similar tendency with heat treating time. Therfore, it was considered that the oxygen content in
-Si3N4 whisker affected the transformation behavior dominently rather than the content of added Si. The added
phase did not affect the transformation behaviro of
Preparation of Monosized Titanium Dioxide Powder from TEOT
Journal of the Korean Ceramic Society, volume 25, issue 5, 1988, Pages 509~517
The controlled Ti(CO2H5)4 hydrolysis reactions for the synthesis of Spherical Monodispersed Titania powders are described. Increasing the concentration of TEOT and the molar ratio of water to TEOT in alcohol solution decrease the reaction time and the particle size. The reaction time is delalyed by increasing the chain length and the number of carbon branches of alcohol as a solvent. The prepared powders with an average diameter of 0.8
and the spherical monodispersed transfer to Rutile phase at 55
Synthesis of Polycarbosilane for SiC Precursor (II)
Journal of the Korean Ceramic Society, volume 25, issue 5, 1988, Pages 518~522
Polycarbosilane was synthesized from polydimethylsilane at 42
, pyrolysis temperature with various times And IR, NMR, UV, and GPC were detected. Average molecular weight Mn was increased proportionally with the reaction time. Average molecular weight of polycarbosilane was about 700(n=20), which has chain structure and the product yield was 72%.
Dielectric and Piezoelectric Properties of Pb(Ni1/3Nb2/3)O3-PbTiO3-PbZrO3 Solid Solution Ceramics
Journal of the Korean Ceramic Society, volume 25, issue 5, 1988, Pages 523~531
The dielectric and piezoelectric properties with compositions in Pb(Ni1/3Nb2/3)O3-PbTiO3-PbZrO3-(PNN-PT-PZ)solid solution ceramics were investigated. In this study, the compsition ranges were 30 PNN 45mole%, 20 PT 50mole% and 50 PZ5mole%. As PT fraction were increased the grain size was increased and the fired density was decreased, but the changes of PNN fraction had no effect on the grain size. The Curie temperature was increased when PT and PNN fraction were increased. The displacement was increased but had a great hysteresis loss when PT fraction was increased. In morphotropic phase boundary, the maximum piezoelectric and electromechanical coupling factor were indicated. Morphotropic phase boundary(MPB) was 34 PT 36mole% in chang of compositions.
Comparative Study on a Special Low-Porosity Portland Cement
Journal of the Korean Ceramic Society, volume 25, issue 5, 1988, Pages 532~540
Even the finest cement as having a specific surface area of 6.000~8.500
/g (Blaine) is to convert into low-porosity hardened cement paste by the use of appropriate plasticizer. In this study, tests were carried out on such a special cement mix(fineness of 6.000
/g, Ca-lignosulfonate plus k2CO3 as plasticizer and W/C=0.25) in comparison with ordinary Portland cement. Owing mainly to the high fineness of the cement powder and the low water-to-cement ratio, the hardened low-porosity cement paste showed a very tight microstructure, the pore texture of which consisted of micropores and wide pores only of small radii. The consequence of such mix was hence that the low-porosity special cement had excellent properties of early-high and very high strengths as compared to ordinary Portland cement. Its volume change when dried in the air or re-wetted, exhibited superor behaviour as well.
Synthesis of Monolithic Gel to Bulk glass-Ceramic in Multicomponent Li2O-Al2O3-SiO2 System
Journal of the Korean Ceramic Society, volume 25, issue 5, 1988, Pages 541~551
The purpose of this investigation was to prepare multicomponent monolithic Li-Al-Si gels of composition(mol%) 16.67 Li2O-16.67 Al2O3-66.67 SiO2 and to convert the gels to monolithic glass-ceramic at low temperature without melting. The hydrolysis, DTA, TGA, TMA, SEM, pore distribution, density and the activation energy for crystallization of the glass-ceramic formation with rawmaterials of which tetraethl orhosilicate of networkforming cation(Si) is partially hydrolyzed, aluminum isoproxide and lithium methoxide prepared by Li-metal react with methanol were studied. The results were as follows : 1) Monolithic gels which were added with additional water, resulting in a total water content 2.5 to 3.0 times the stoichiometric amount required to fully hydrolyze the alkoxides. 2) Specimens were dried to form crylinders 60mm in length and 40mm in diameter in about 800 hrs at 5
-eucryptite crystals and
-spodumene crystals were detected in samples heated above 75
. 4) Within the temperature and range of 25-50
the thermal expansion coefficient for crystallized samples were shown as 2.6-5.7
, respectively. 5) The activation energy for the crystal growth was 11.01kcal/mol at 794
Preparation of Low Voltage ZnO Varistor Using Seed Grain Method and Its Electrical Properties
Journal of the Korean Ceramic Society, volume 25, issue 5, 1988, Pages 552~560
ZnO low voltage varistor was obtained by varying a) the amount of seed grains, b) the size of seed grains, and c) sintering temperature. Also, the optimum condition for fabricating the ZnO seed grains was studied. Large ZnO seed grains were obtained by washing a ZnO sintered body containing 1m/of BaCO3 in boiling water. When the seed grains were added, abnormal grain growth occurred, and the varistor voltage sharply decreased. However, when more than 5w/o of seed grain content was added, the varistor voltage gradually increased. When 10w/o seed grains of 75~106
were added and sintered for 2 hours at 1200 to 125
, low voltage varistor properties with V1mA/mm of 19V/mm and nonlinear exponent (
) of 12 occurred.
Synthesis of Silicon Nitride from Ethyl Silicate(II) : Effect of Additive on the Nitridation of Silicon Nitride
Journal of the Korean Ceramic Society, volume 25, issue 5, 1988, Pages 561~569
Mixtures of very small amounts of additive, carbon and silica(about 0.46
) which synthesized by the hydrolysis of ethyl silicate, the molar ratio of SiO2/C was fixed to 1/10, was nitrided at 145
. It was considered that the optimum amount of additive to promote the nitridation reaction was below 2.0wt%. By the addition of additive, the nitridation reaction was promoted and formation of
-Si3N4 was promoted at 145
for 1hour, but, the nitridation reaction was decreased and the ratio of
of Si3N4, was increased at 145
for 5 hours. The crystal phase was
phase and the nitridation reaction was promoted and the particle size of silicon nitride was become smaller by the addition of
-Si3N4, but silicon nitride of whisker-like form was produced by the addition of transition elements. There was a difference in the lattice constants of
-Si3N4, but no difference in its of
-Si3N4 according to kinds of added substance and reaction time.