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 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
Selecting the target year
Contribution of Components of ZrF4-Based Glasses to IR Edge Absorption
;;C. T. Moynihan;
Journal of the Korean Ceramic Society, volume 25, issue 1, 1988, Pages 1~6
The IR edge absorption of the important pure components of ZrF4-based glasses, including two previously uncharacterized components(ZrF4 and AlF3), has been measured. Values of the glass IR edge absorption coefficients have been calculated from these results, assuming additivity, and are compared with experimental glass absorption coefficients. The calculated
values are about a factor of two lower than the experimental values for ZrF4-based glasses, and the ZrF4 makes the largest contribution to the calculated
Piezoelectric Properties on the Thickness of Specimens with PZT/Epoxy Composite Materials of 1-3 Connectivity
Journal of the Korean Ceramic Society, volume 25, issue 1, 1988, Pages 7~14
In this paper, piezoelectric composite materials of 1-3 connectivity were prepared by using "dicing-filling" technique with PZT ceramics and epoxy polymers, and the dependence of piezoelectric properties on the thickness of specimens was investigated. In case that the PZT volume percent is 18.1%, according to an increment of thickness, the dielectric constant of composites( 33) is unchangeable, which is about 200, the piezoelectric coefficient (d33) is somewhat increased, which is about 240-280 (PC/N) and the electromechanical coupling factor of thickness mode(kt) is proportioned, but radial mode(kp) is constant.
The Effect of Seawater on the Hydration of Clinker Minerals (II) Acceleration Experiment in the Artificial Seawater
Journal of the Korean Ceramic Society, volume 25, issue 1, 1988, Pages 15~20
In this study, the specimens of cement clinker minerals such as 80C3-S-15C4AF-5C3A added various blending materials were immersed in artificial seawater. In order to ascertain the effect of SO3 and blending materials on seawater resistance of the specimens, the acceleration experiment in the artificial seawater was carried out by repeating of immersion and drying operation periodically. As inner part of the specimen immersed in artificial seawater, Friedel's salt was produced by reaction with Cl ion. In outer part of the specimen, gypsum and ettringite were mainly formed. With the increase of SO3 content in the specimen the formation of ettringite was increased and Frieldel's salt in inner part was decreased. Total pore volume of the specimens was increased according to the amount of Cl ion penetrated and Mg(OH)2 leached in the solution.
Piezoelectric Properties of PSN-PMN-PT-PZ System
Journal of the Korean Ceramic Society, volume 25, issue 1, 1988, Pages 21~26
The piezoelectric properties and temperatureproperties of resonant frequency of the pseudoquaternary soild solution 0.075 Pb(Sb
)O3-0.025 Pb(Mn1/3Nb2/3)O3-xPbTiO3-(0.9-x) PbZrO3 were investigated. The composition range examined are 0.32 x 0.57. Specimens were prepared by the conventional mixed oxide technique, calcined at 850
for 1 hour and sintered at 1270
for 2 hours under PbO atmosphere. From the results of XRD, dielectric and piezoelectric properties, it is supposed that the MPB composition between tetragonal and rhombohedral ferroelectric perovskite exists in 0.42
was considered at the nearby MPB.
Structural Analysis of
System Glasses by FT-IR and Raman Spectroscopy
Journal of the Korean Ceramic Society, volume 25, issue 1, 1988, Pages 27~34
In order to investigate the reason of changes in the physical properties of glasses near the region for which R(Ga/Na)=1, spectroscopic studies using FT-IR and Raman spectroscopy have been carried out on Na2O.2SiO2 glass with addition of Ga2O3 from 0 to 35 mole %, i.e., from R=0 to 1.61. The main purpose of this work is to investigate the coordination number of Ga3+ in glass with variation of glass composition and to determine the existence of tricluster in the Ga-rich region for which R>1.0 in Na2O-Ga2O3-SiO2 system.
Solid Solution and Defect Structure of LiCrO2 in the Pseudo-binary Systems : Li2Cr2O4-MgAl2O4
Journal of the Korean Ceramic Society, volume 25, issue 1, 1988, Pages 35~41
In the system of Li2O-MgO-Al2O3-Cr2O3, the crystalline solid solution of LiCrO2 along the pseudo-binary join between rocksalt structure(LiCrO2) and spinel structure(MgCr2O4 or MgAl2O4) have been investigated by x-ray diffraction techniques. In this study, order-disorder phase transition of LiCrO2 was observed and the unit cell of the disordered LiCrO2 structure has been established. It has been found that LiCrO2 makes a solid solution over a wide range with MgAl2O4, while not with MgCr2O4. This difference was explained as being due to the ability of oxygen lattice distortion which depended on the relative sizes and chemical bonding characteristics of the substituted ions.
Effect of Additives on the PTCR Characteristics of La3+ Doped(Ba1-xCax)TiO4 Ceramics
Journal of the Korean Ceramic Society, volume 25, issue 1, 1988, Pages 42~48
Commercially available PTCR (Postive Temperature Coefficient of Resistivity) ceramics which have low room temperature resistance, high PTC effect and temperature coefficient were prepared by La3+ doped semiconducting barium calcium titanate soild solutions. PTCR characteristics were remarkably improved by addition of AST (1/3 Al2O3
1/4TiO2) and MnCl2. That can be explained by formation of liquid phase during sintering and acceptor level on the intergranular layer. Resistivity anormaly increased with decreasing cooling rate. Optimum manufacturing conditions were cooling rate below 100
C/hr, Ca and Mn content of 4 mol% &, 0.09-0.12mol% respectively.
Synthesis of Polycarbosilane for SiC Precursor
Journal of the Korean Ceramic Society, volume 25, issue 1, 1988, Pages 49~53
Polycarbosilane was synthesized from the pyrolysis of polydimethylsilane, which is dechlorinated from dimethyldichlorosilane. The pyrolysis temperature was varied at 280-480
for 2 hours. FT-IR, FT-NMR and GPC measurement were studied on the residue inside the reaction crucible and viscous solution inside the cooling zone respectively. From the viscous solution in the cooling zone at 420
, the synthesis of polycarbosilane wa well detected.
Powder Preparation and Sintering Properties of PZT-Ceramics by Coprecipitation
Journal of the Korean Ceramic Society, volume 25, issue 1, 1988, Pages 54~58
In order to depress PbO vaporization during calcination and improve sinterability in low temperature, a method for preparing homogeous Lead-Zirconate-Titanate (PZT) powder from aqueous salt solution by precipitation is described. In this method, single phae PZT fine powders are formed at above 500
. PZT-ceramics using these powders have high sinterability, and good sintering characteristics relatively low temp. (-high apparent density, low porosity, low water adsorption etc.)
Preparation of Porous Glass Membranes by the Phase-Separation Technique
Journal of the Korean Ceramic Society, volume 25, issue 1, 1988, Pages 59~65
To develop porous glass membranes used for a effective membrane-separation process, porous glasses and glass membranes were prepared from the sodium borosilicate parent glass by the phaseseparation technique and effects of heat-treatment and leaching conditions on their characteristics were investigated. The crack-free glass membranes could be fabricated from the 9.4 Na2-O-30.7 B2O3-59.2 SiO2-0.7 Al2O3(wt%) parent glass by heat-treatment at the lower temperature(550-570
) and for longer than 45 hrs for the phase separation, followed by leaching with 3N-HCl＋60% ethylene glycol solution at 90
over 25 hrs. Porous glasses prepared in this work showed large specific surface areas(400㎡/g) and narrow pore size distribution with the mean pore radius of 14
enough for the application as reverse osmosis membranes. The salt-rejection efficiency and product-flux of the glass membranes heat-treated at 570
for 80 hrs were found to be 51.8% and 270cc/㎡. hr, respectively. This result suggests that the porous glass membranes fabricated in this study could be applied for the reverse osmosis process.
Effect of Salt on the Formation of
-Calcium Sulfate Hemihydrate from by-Product Gypsum of Phosphoric Acid Process in Aqueous Salt Solution at Atmospheric Pressure
Journal of the Korean Ceramic Society, volume 25, issue 1, 1988, Pages 66~72
The effect of salts on the formation of
-hemihydrated gypsum at boiling temperature under atmospheric pressure was studied by the solubility measurement method, and the formation of
-hemihydrated gypsum from by-product gypsum of phosphoric acid process in the salts solution were investigated. The order of catalytic effect of salt on the formation of
-hemihydrated gypsum are as follows: NH4Cl>NaCl>NaNO3. In the salts solution of sodium nitrate, sodium chloride, and ammonium chloride, prismatic
-hemihydrated gypsum was obtained and the crystal form was converted to needle form in complex solution with sulfuric acid. The P2O5 content in gypsum was largely decreased in this atmosphoric solution process.
Synthesis of Single Crystal and Polymorphism of KAlSiO4
Journal of the Korean Ceramic Society, volume 25, issue 1, 1988, Pages 73~77
Single crystals of kalsilite were synthesized by hydrothermal method at 420
and 100 atm-1500 atm. The crystal habits are similar to those of KLiSiO4 single crystals. The crystal structure was investigated by means of X-ray single crystal diffraction. The space group of kalsilite is P63. Phase transitiions were determined by use of DTA and high temperature X-ray Guinier camera. Phase transitions of kalsilite are summerized and discussed.
Crystal Growth of LiNbO3 for SAW Devices
Journal of the Korean Ceramic Society, volume 25, issue 1, 1988, Pages 78~82
Good quality LiNbO3 single crystals which can be applied to SAW devices, were grown by Czochralski method. It was observed that the gas-bubbles were concentrated in ring shape at the outer part of grown crystals, and this anomaly was illustrated by modeling the mechanism of gas-bubble entrapment according to the melt flow pattern in the crucible. And this mechanism was also encertained by observation of solid-liquid interface shape of grown crystals. The optimal condition for good quality crystals was known that the solid-liquid interface shape was slightly concave.
Phase Equilibria in the System Y2O3-BaO-CuO
Journal of the Korean Ceramic Society, volume 25, issue 1, 1988, Pages 83~87
Phase relationships in the system Y2O3-BaO-CuO were investigated at 950
by XRD, SEM and EPM analysis. It was found that there was a new phase that has not been awared yet, closely near the range of sharing 123 and 211 compounds.