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 29, Issue 12 - Dec 1992
Volume 29, Issue 11 - Nov 1992
Volume 29, Issue 10 - Oct 1992
Volume 29, Issue 9 - Sep 1992
Volume 29, Issue 8 - Aug 1992
Volume 29, Issue 7 - Jul 1992
Volume 29, Issue 6 - Jun 1992
Volume 29, Issue 5 - May 1992
Volume 29, Issue 4 - Apr 1992
Volume 29, Issue 3 - Mar 1992
Volume 29, Issue 2 - Feb 1992
Volume 29, Issue 1 - Jan 1992
Selecting the target year
A Study on Microstructure and Electrical Properties in Pb(
Journal of the Korean Ceramic Society, volume 29, issue 9, 1992, Pages 675~680
The purpose of this investigation was to study the stability of perovskite structure, the variation of electrical properties and a microstructure with varing amount of PbTiO3 additive in PZN-PT-BT system. The results are as follows: 1. The pyrochlore phase was reduced as the amount of PbTiO3 additive was increased and completely eliminated at 0.15PT in PZN-PT-BT system. 2. The aging rate was increased in proportion to tetragonality because the internal stress was increased in proportion to tetragonality. 3. On increasing the amount of PbTiO3 additive, the Curie temperature was increased in proportion to tetragonality. 4. As the amount of PT in the composition increase, the variation of dielectric constant was sharpened and the diffuseness of the transition decreased.
Process Control for the Synthesis of Ultrafine Si3N4-SiC Powders by the Hybrid Plasma Processing
Journal of the Korean Ceramic Society, volume 29, issue 9, 1992, Pages 681~688
Ultrafine Si3N4 and Si3N4+SiC mixed powders were synthesized through thermal plasma chemical vapor deposition(CVD) using a hybrid plasma, which was characterized by the supersposition of a radio-frequency plasma and arc jet. The reactant SiCl4 was injected into an arc jet and completely decomposed in a hybrid plasma, and the second reactant CH4 and/or NH3 mixed with H2 were injected into the tail flame through double stage ring slits. In the case of ultrafine Si3N4 powder synthesis, reaction efficiency increased significantly by double stage injection compared to single stage one, although crystallizing behaviors depended upon injection speed of reactive quenching gas (NH3+N2) and injection method. For the preparation of Si2N4+SiC mixed powders, N/C composition ratio could be controlled by regulating the injection speed of NH3 and/or CH4 reactant and H2 quenching gas mixtures as well as by adjusting the reaction space.
Single Crystal Growth by Verneuil Method
Journal of the Korean Ceramic Society, volume 29, issue 9, 1992, Pages 689~694
Strontium Titanate single crystal is grown by Verneuil method. Feed materials were prepared by coprecipitation method which started with Sr(NO3)2 and TiCl4. SrTiO3 can not be grown from feed materials having the stoichiometric components due to volatilization of SrO, when the powder added more 3 wt% SrO used, the crystal can be grown. Growth conditions that the pressure of oxygen and hydrogen gas was 5 psi, the flow rate of oxygen and hydrogen was 7.3 and 30ι/min respectively, the growth rate was 20 mm/hr were optimum. The grown single crystal has the diameter of 10~15 mm and its length is 30~40 mm. The grown crystal was deep brown color and somewhat transparent. The color of grown crystal was lightened after annealing.
Fabrication and Piezoelectric Strain Characteristics of PLZT Functionally Gradient Piezoelectric Actuator by Doctor Blade Process
Journal of the Korean Ceramic Society, volume 29, issue 9, 1992, Pages 695~704
In (Pb, La)(Zr, Ti)O3 ceramic system, the functionally gradient material (FGM) was developed, and its processing and properties were investigated. The FGMs were successfully prepared through doctor blade method with acrylic binder system as well as mold stacking press method. The ultrasonic treatment was very effective for particle dispersion in slurry, and it lead to form clack-free green films. The strain-voltage characteristics of the FGM system was significantly improved which fabricated between a high piezoelectric-low dielectric and a low piezoelectric-high dielectric composition layer.
Development of a Miniaturized Electrochemical Sensor for Ionic Electrochemical Potential Mapping
Journal of the Korean Ceramic Society, volume 29, issue 9, 1992, Pages 705~710
For the ultimate purpose of mapping, with a high precision, the local electrochemical potentials of an ionic carrier in nonisothermal conditions, an ionic probe for Ag+ ions, Pt/Ag/AgI, has been miniaturized to a tip size of 20∼30
, by an electrochemical technique combined with gas (I2)/solid (Ag) reaction, and its performance checked by measuring the partial electronic and ionic conductivities of Ag2S from the ion and electron blocking cells, Ag/Ag2S/Pt and Ag/Ag2S/AgI/Ag, respectively. The results have firmly confirmed that the miniaturzed probe function quite validly and be very promising.
Initial Particle Size Effects on Sintering and Dielectric Properties of $Pb>(Fe_1/2Nb_1/2)O_3$
Journal of the Korean Ceramic Society, volume 29, issue 9, 1992, Pages 711~718
Pb(Fe1/2Nb1/2)O3 was prepared by the molten salt synthesis method using an equimolar mixture of NaCl-KCl. Initial particle size could be controlled by varying the weight ratio of the NaCl-KCl to raw materials from 0.1 to 1.0, and the initial particle size effects on the sintering and dielectric properties of Pb(Fe1/2Nb1/2)O3 were investigated at the sintering temperature range from 90
. As the weight ratio of salt increased, the average particle size decreased and the particle size distributions tended to narrow. As the initial particle size decreased, the linear shrinkage and density increased due to the promotion of densification. Dielectric constant increased with decreasing the initial particle size resulting from the increase of density and grain size.
Composites Using the Silica Sol Infiltration Method
Journal of the Korean Ceramic Society, volume 29, issue 9, 1992, Pages 719~728
ZrO2/Al2O3-Mullite composites were prepared by infiltration of the silica sol to the porous ZrO2/Al2O3 bodies. The porous ZrO2/Al2O3 bodies for infiltration were fabricated using ZrO2 (20wt%)/Al2O3 composite powders synthesized by the emulsion-hot kerosene drying method. The preparation of silica sols was conducted by the hydrolysis-peptization of an alcoholic TEOS solution. When ZrO2/Al2O3-Mullite and ZrO2/Al2O3 composites were sintered at 1
for 4 hrs, both of them showed an excellent sinterability. As the amount of mullite added in the composites increased, the ratio of the tetragonal phase of zirconia to the monoclinic phase at the room temperature became higher. It was known that values of the fracture toughness of the ZrO2/Al2O3-Mullite composites were about 5.48 MPa.m1/2 much larger than that of the ZrO2/Al2O3 system.
Formation and Structure of
Journal of the Korean Ceramic Society, volume 29, issue 9, 1992, Pages 729~738
The glass formation and structural change with the glass compositions were investigated in the CaO-P2O5-SiO2 system with less than 40 wt% of P2O5. The glass formation range was determined by XRD, SEM and EDS techniques for water quenched specimens. The structural analyses were made for binary CaO-SiO2 glasses and ternary CaO-P2O5-SiO2 glasses by using FT-IR and Raman spectroscopy. The glass formation was affected by CaO/SiO2 mole ratio, P2O5 content and primary crystalline phase. The stable glass formation range was found when the transformed CaO/SiO2 mole ratio (new factor derived from structural changes) was in the range of 0.72~1.15 with less than 10 mol% of P2O5. The structural analyses of CaO-SiO2 glasses indicated that as the CaO/SiO2 ratio was increased, the nonbridging oxygens in the structural unit of the glasses were increased. With addition of P2O5 to CaO-SiO2 glasses, the P2O5 enhanced the polymerization of [SiO4] tetrahedra unit in CaO-SiO2 glasses, which contained a large portion of nonbridging oxygen. The phosphate eliminated nonbridging oxygens from silicate species, forcing polymerization of silicate structures and produced in [PO4] monomer in glasses. When added P2O5 was kept constant, the structural change with various CaO/SiO2 ratio was very similar to that of CaO-SiO2 glasses.
Development of Ceramic Composite Membranes for Gas Separation: II. Preparation and Coating Characteristics of Nanoparticulate
Journal of the Korean Ceramic Society, volume 29, issue 9, 1992, Pages 739~749
The sols prepared by dialyzing solutions, in which the hydrolyzed precipitates of TEOT or directly Ti(OC3H7)4 were resolved, were the nanoparticulate sol with the average particle size less than 7 nm and the anatase crystal phase. In the pH range of 1.5 to 2.9, the particle size of the nanoparticulate TiO2 sols (0.09 mol/ι) increased gradually upto 15 nm~26nm with the increase of pH in the initial aging state but the sols were transparent all the time, and stable without growin any more after 30 days. When the slipcasted porous alumina tubes were coated by the sol-gel dipping method, the minimum particle size and the aging time for forming the coated gel layer at the given pH were optimized. For obtaining the very thin crack-free and reproducible membrane coating, the use of a nanoparticulate TiO2 sol (0.09 mol/ι) aged for about 30 dyas at pH=2.0 was found to be the best.
Preparation of Si-SiC Composites by Si-Infiltration
Journal of the Korean Ceramic Society, volume 29, issue 9, 1992, Pages 750~756
Reaction bonded si-SiC composites were prepared by silicon infiltration technique at temperature of 1
for 30 minutes in vaccum atmosphere. The microstructure and mechanical properties of Si-SiC composites were investigated and characterized. UF-15 and SE-10 as SiC powders, phenolic resin and carbon black as carbon source, and metallic silicon powder as molten Si source were used as starting materials. New SiC crystallines nucleatd and grown by reaction of Si and C were detected by TEM and SEM-EDS. The bonding between new and original SiC was found to be strong. But the wetting of SiC by unreacted metallic Si and the rapid grain growth of new SiC decreased density and fracture toughness. Fracture toughness and modulus of rupture of Si-SiC composite were about 3.2 MPa.m1/2 and 480 MPa, respectively.