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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 17, Issue 4 - Apr 1980
Volume 17, Issue 3 - Mar 1980
Volume 17, Issue 2 - Feb 1980
Volume 17, Issue 1 - Jan 1980
Selecting the target year
Effect of Fluorides on Mullitization of
System; Korean Kaolin
Journal of the Korean Ceramic Society, volume 17, issue 2, 1980, Pages 61~68
The effect of the addition of various fluoreides on the mullitization of Korean crude kaolin was studied by X-ray powder diffraction and scanning electron microscopic methods. Kaolin without any addition of fluoreides began to be transformed into the mullite at 1, 10
. Mullite peaks were discernible in the X-ray diffraction patterns of the specimens which contained fluorides equivalent to about 2 wt % fluorine, and which were sintered at 1, 05
. The higher the concentration of fluorine in kaolin, the lower was the initiatinig temperature of mullitization. Experiments , for example, showed that mullite could be formed at 95
from kaolin mixed with 3.4% fluorine. Of the fluoride, addtives, sodiumsiliconfluoride
was must effective in mullite formation of kaolin. In order of accelerating mullitization, the fluorides except
could be placed in following sequence ; (1) sodium (NaF) (2) aluminium
(3)potassium(KF) (4) ammonium
. It was considered that the intrinsic characteristics of fluorides, such as size of ionic radiu, charge , bond strength between cation and anion, and electronegativity of cation affected millitization of halloysite, a main constituent mineral of kaolin.
A Stydy on Steel Wire Fiber Reinforced Refractory Castable
Journal of the Korean Ceramic Society, volume 17, issue 2, 1980, Pages 69~74
This study deals with the wire content, wire diameter, aspect ratio , it's arrangement of steel, wire fiber and the sorts of castable which affected the character of steel wire fiber reinformced refractory castable. Two kinds of alumina based refractory castables, one is for 1650℃ and the other is for 1800℃, and stainless steel which is SUS 304 type 0.25, 0.34 , 0.37 and 0.50m/min diameter were used respectively. Aspect ratio was adjusted to 50, 75, 100 and steel fiber content was also adjusted to 1-4wt% each. The results of the experiment were as follows : 1. At firing temperature around 1,000℃, MOR is increased with increasing wire content and aspect ratio with decreasing firing temperature, which depends on the Romualdi's Fiber Spacing Theory. But for calculation of the fiber spacing, Swamy equation is more a aplicable to the extensive fiber mixing conditions. However, the condition differs from the above at firing temperature around 1,350℃ ,because of the degradation of wire and the progress of sintering of castable. 2. Linear change is getting larger corresponding to the increase of wire content, and the spaling resistivity is increasing corresponding to the increase of wire content and to aspect ratio, and with decreasing wire diameter. 3. Firing shrinkage under load is getting greater as higher wire content, and the shrinkage of the test pieces which fiber is vertically oriented is getting greater than the test pieces which fiber is randomly oriented.
Effect of Antimony Sesquioxide on the Dielectric Property of Rutile
Journal of the Korean Ceramic Society, volume 17, issue 2, 1980, Pages 75~79
The effect of the additive on the dielectric property of
containing 0-2.5wt %.
was investigated as a function of frequency from
cps and temperature from 25 to 375
. The dielectric constant increased with increasing
concentration from 0.25 to 0.5wt.% It is due to space charge polarization caused by increasing anion vacanices. The dielectric constant decreased for further increase in
concentration. It can be explained by increasing grain size effect rather than space charge polarization.
The Effect of
Addition on Sintering Phenomena and Electro-mechanical Properties of PZT
Journal of the Korean Ceramic Society, volume 17, issue 2, 1980, Pages 80~88
The sintering phenomena and piezoelectric properties of PZT ceramics of composition
were investigated when a small quantity of
were added. The unwanted chemical composition change in PZT during sinterin porces du to PbO evaporation poses a severe problem in PZt manufacturinig. It is observed tat an addition of small amount of
to PZT markedly decreases the evaporation of PbO during sintering . The green compact of (1-x) PZT.xLaMnO3(x=0.02~0.10) could be sintered of under O2 atmosphere alone with no significant loss of PbO. The planar coupling factor kp of the sintered
is similar to that of commercial PZT 6A. Microstructure investigation shows that part of sintering process of
system progresses via liquid phase sintering. It is believed that the evaporation of PbO in PZT sintering is restricted by the addition of
due to the above phenomena. Furthermore the solid solution of
in PZT causes diffuses phase transition.
The Effects of Non-Stoichiometry and Sintering Temperature on the Magnetic Properties of Ni-Zn Ferrites
Journal of the Korean Ceramic Society, volume 17, issue 2, 1980, Pages 89~95
The effect of non-stoichimetry and sintering temperature on the magnetic properties of materials in the system
have been investigated. The value of x used in initial weighing of oxides were varied from -0.04 to -0.12. The value of x, however, appears to be from +0.04 to -0.04 after ferrite powder preparation due to iron pick up during ball mill mixing and grinding. The densities of specimens which were deficientinrion were higher than those with excess ion. Specimens with near stoichiometric composition showed maximum initial permeability an dminimum coercivity whereas high values of quality factor (Q) were observed in iron deficient specimens. The quality factor decreased monotonically with increasing sintering temperature, but the permeability showed maxima with increasing sintering temperature. Thus highest value of figure of merit
Q was obtained in composition
sintered at 100
for 3 hrs. in an air atmosphere.
A Study on the Development of Refractories for the Iron , Steel and Cement Manufacturing
Journal of the Korean Ceramic Society, volume 17, issue 2, 1980, Pages 96~100
The castable refractory, CaO.
is a useful alumina cement for iron, steel and cement for iron, steel and cement industries, however it is difficult to produce CaO.
because of its high melting point(180
) and narrow firing range. In this study, the coprecipitation method was used to produce CaO.
for lower temperature firing . This method involved the titration of mixed solution of calicum and aluminate which extracted from domestic kaolin with
solution under blowing
gas into the solution. The coprecipitate and its clacined products were analyzed by X-ray diffraction and DTA. The calcined products fired between 400 and 90
were amorphous, but at 100
the coprecipitate was converted into one compound, CaO
. From those experimental results, it was found that we could synthesizze CaO.
at about 100
which is lower than conventional firing temperature by around 80
. The refractoriness of this alumina cement was SK 34 and the compressive strength ( 1 day) was about 250kg/