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 24, Issue 6 - Jun 1987
Volume 24, Issue 5 - May 1987
Volume 24, Issue 4 - Apr 1987
Volume 24, Issue 3 - Mar 1987
Volume 24, Issue 2 - Feb 1987
Volume 24, Issue 1 - Jan 1987
Selecting the target year
Electrical Conductivity of Vacuum Evaporated Al Films on Glass
Journal of the Korean Ceramic Society, volume 24, issue 2, 1987, Pages 101~110
The relative electrical conductivity of vacuum deposited Al films on a soda-lime(2947) and an alumino boro silicate(7809) glass was investigated with the variation of the relative humidity,temperature and film thickness. The structure and microstructure of Al films before and after exposure to the humidity wereexamined by the X-ray Diffractormenter(XRD) and Scanning Electron Microscope(SEM). As the relative humidity increased, the electrical conductivity of Al films on both glasses was decreased. However, the Al films on 7809 glass showed higher conductivity than that of 2947 glass under the same testing conditions. The decreasing of electrical conductivity was caused by the formation of Aluminum hydroxide which was made by the reaction between the aluminum films and water vapor.
A Study of PTCR Effects in Semiconducting BaTiO3 Prepared by Direct Wet Process
Journal of the Korean Ceramic Society, volume 24, issue 2, 1987, Pages 111~116
By the method of direct wet process which has been developed in our laboratory, the high purity BaTiO3 powders could be synthesized from the room temperature to 90
according to particle sizes. For to detect the PTCR effects, Sb2O3 wasdoped in the BaTiO3 powders which had been prepared on above method. As the results, the PTCR effects were in creased with the decreasing grain size of BaTiO3 powders.
Studies on AlF3-(Mg＋Sr＋Ba)F2-P2O5 Glasses I. Glass Forming Ranges of Fluorophosphate System and Its Various Properties
Journal of the Korean Ceramic Society, volume 24, issue 2, 1987, Pages 117~122
Glass forming ranges in the AlF3-(Mg＋Sr＋Ba)F2-P2O5 system are studied and ultraviolet transmission, infrared transmission, coefficient of refractive index, thermal expansion coefficient, density and chemical durability of the glasses are determined. Glass forming range is restricted MgF2 0-10wt%, SrF2 10-50wt%, BaF2 10-40wt% in this system. While BaF2 is substituted by SrF2, density and refractive index are decreased, micro hardness and thermal expansion coefficient are increased according to the increasing of SrF2 at fixed MgF2 contents. These samples represent high transmittance(93%) from 400nm to 3800nm and chemical durability of these samples show less than 0.3mg/
hy by weightloss.
Effect of M2O3 on the Sinterbility and Electrical Conductivity of ZrO2(Y2O3) System(III) : Ceramics of the ZrO2-Y2O3-Ln2O3 System
Journal of the Korean Ceramic Society, volume 24, issue 2, 1987, Pages 123~132
Yttria-stabilized zirconia with erbia-lanthana were investigated with respect to the amount of Ln2O3 (Ln; Er, La) addition in the range of 0.5∼5 mol% to the base composition of 8 mol% yttriazirconia. Following analysis and measurement were adopted for the characterization of synthesizes of solid electrolyte; phase transformation, lattice parameter, crystallite size, relative density, chemical composition and SEM/EDS. Electrical conductivity by two-probe method versus temperature from 350
and frequency in the range of 5Hz∼13MHz by complex impedance method was also conducted together with the determination of oxygen ion transference number by EMF method for the evaluation of their electrical properties. The results were as followsing; Electrical conductivity were decreased with increase in Ln2O3 content, but their activation energies increased. In the case of La2O3 addition, espicially, its electrical conductivity was decreased owing to the segregation of second phases at the grain-boundary. Grain-boundary conductivity of the specimen contained 0.5 mol% Er2O3 exhibited a maximum conductivity among thecompositions experimented. However, their bulk conductivities decreased in both case. Oxygen ion transference number was also reduced with decrease in oxygen partial pressure. For example, in the case of Er2O3 addition it retained value in the range of 0.97∼0.94 abvove 4.74
10-2in oxygen partial pressure. With the increase in the quantities of the evaporation of additive components, the crystallite size of stabilized zirconia decreased, and their relative density also reduced owing to the formation of porosity in their matrices. In the case of La2O3 the sinterbility was improved in the limited amount of addition up to 0.5 mol%, in the same range of addition the strength of sintered bodies were improved perhaps owing to the precipitation of metastable tetragonal phase in the fully stabilized zirconia.
Early Hydration of Tricalcium Silicate(II)
Journal of the Korean Ceramic Society, volume 24, issue 2, 1987, Pages 133~138
The behavior of CaO and SiO2 in the reaction produced which produced in the early hydration of C3S was studied by XRD and thermal analyzer. Polymerization of hydrated siltcates was also studied by TMS method. TMS derivatives were separated by gaschromatography. Cao/SiO2 molar ratios of the produced CSH gel under the air atmosphere were higher than that in the CO2. Dimerization rate of hydrated silicates was very fast in the early hydration stage. Trimer began to appear later than dimer and its increasing rate was very low. The amount of dimer and trimer formed under the CO2 atmosphere was less than that in the air.
Properties of Powders and Sintered Bodies of
-SiC Prepared from Jecheon Quartzite
Journal of the Korean Ceramic Society, volume 24, issue 2, 1987, Pages 139~146
-SiC powders were prepared by the simultaneous reduction and carbiding of Jecheon quartzite at 1400
for 7 hours in hydrogen atmosphere, using graphite or carbon black as the reducing and carbiding reagent. The prepared SiC powder was acid-treated with the mixture of fluoric acid and hydrochloric acid at room temperature and also by heating on an alcohol lamp for one hour, respectively. The impurities were mostly eliminated and the purity of SiC became 98.5% after hot acid treatment. The specific surface area of SiC powder was also increased up to 115㎡/g by hot acid treatment. This pure and fine SiC powder was hot-pressed at 1900
for 30min, using 5wt% Al2O3 as a sintering aid. The density, M.O.R., KIC and hardness of the hot-pressed SiC ceramics were 3.195g/㎤, 48.7Kgf/
, 5.4MN/㎥/2 and 2,182Kgf/
Synthesis of Silicon Nitride from Kimcheon Quartzite
Journal of the Korean Ceramic Society, volume 24, issue 2, 1987, Pages 147~154
Silicon nitride powders were prepared by the simultaneous reduction and nitridation from powder mixtures of Kim cheon quartzite and carbon (graphite or carbon black) at1400
for 10 hours in nitrogen atmosphere. The effects of the reaction variables on the yield of products and on the
ratio were examined. The average particle size, density, and the
ratio of the obtained si3N4 were 1.0
, 3.10g/㎤ and 90/10, respectively. It was found that the Si3N4 powders obtained in this work were comparable to the foreign commercial products.
A Study on Stabilized CdS-CdSe Red Stain part III, Application of
Stain to Ceramic Body
Journal of the Korean Ceramic Society, volume 24, issue 2, 1987, Pages 155~160
The investigation includes the application of
stain to ceramic body. The currently developed stain was compared to the commercially available stain in applying to ceremic glaze. Two stains (currently developed and commecially available) were mixed with frits and applied to ceramic tiles. The tiles were fired at 850 to 120
and tested by colorimeter in X.Y.Z. axis of the wavelength ranging from 580nm to 650nm. Applicability 18 stains to ceramic body was investigated by ISCC-NBS of Munsell color nomenclature.
stain is as good as V and Pr series stain in mixing composition of frits 9 to 1. It maintains red color at 100
in the mixture of frits, and shows as the strong acid resistance stain.
Design of Down Draft Kiln for Gas Firing II. Behavior of Flame
Journal of the Korean Ceramic Society, volume 24, issue 2, 1987, Pages 161~169
An experimental study of the characteristics and the behavior of flames, and the aerodynamic flow pattern was carried out in the present work on a down draft kiln for gas firing. The aim of this work is to establish a behavior of flames and to know the extent to which the flow pattern is affected by the height of baffle plate. The measurements of temperature, concentrations of fuelgas, and kiln pressure were conducted at different temperature in kiln, and at different height of baffle plate. From the obtained results, it was found that the characteristics of thestagnation zone are greatly affected when changing over the height of baffle plate, and the best condition of that was 115m/m.
Effects of PECVD Process Parameters on the Characteristics of SiN Thin Film
Journal of the Korean Ceramic Society, volume 24, issue 2, 1987, Pages 170~178
Changes of the properties of PECVD-SiN film with the variation of deposition process parameters were investigated and optimum process parameters were determined. The refractive index of the film increased with increasing substrate temperature and pressure, and decreasing rf-power, NH3/SiH4 gas ratio and total gas flow. BHF etch rate and deposition rate show a decreasing tendency with increasing refractive index. The step coverage of the film was not affected much by deposition rate and pressure, but improved apparently with increasing rf-power and NH3/SiH4 gas ratio. Also the optimum process parameters were determined by considering the characteristic properties as well as thickness uniformity of films. The refractive index of the film deposited under this condition was 2.06.
Electrical Conductivity of MgO-doped Cr2O3
Journal of the Korean Ceramic Society, volume 24, issue 2, 1987, Pages 179~185
The microstructure and the electrical conductivity of MgO-doped Cr2O3 were investigated as a function of oxygen partial presure, temperature, and MgO content. The grain size was estimated about 1.0
. The solubility limit is increased with oxygen partial pressure. Above the solubility limit of MgO in Cr2O3, the spinel phase(MgCr2O4) is formed by the reaction of MgO and Cr2O3. The electrical conductivity of MgO-doped Cr2O3 within the solubility limit is increased with MgO content. Above the solubility limit, however, it is decreased with increasing MgO content because of the formation of the spinel phase.
The Study on the Preparation of PSZ from the Domestic Zircon Sand its Applications I. Preparation of the High Purity Zirconia Powder form Domestic Zircon Sand
Journal of the Korean Ceramic Society, volume 24, issue 2, 1987, Pages 186~192
ZrO2 powders having high purity were prepared from domestic zircon sand using the caustic fusion method and the soda ash sintering process. In the caustic fusion method, ZrO2 recovery was reached to 96% when 100/140 mesh zircon was reacted with NaOH at the NaOH/Zircon mole ratio 6 and at 650
for 2 hours. And in the soda ash sintering process, ZrO2 was recovered to 88.5% when -325 mesh zircon was reacted with Na2CO3 at the Na2CO3/Zircon mole ratio 1.1 and 1050
for 2 hours. In both cases, Zr component was extracted to ZrOCl2, subsequently crystallized to ZrOCl2
8H2O to increase the purity, and converted to ZrO2 by precipitation. And to increase the sinter ability of powder, Cl- ion was removed and strong agglomeration was avoided by methanol distribution of Zr(OH)4 precipitates.