• Journal of the Korean Crystal Growth and Crystal Technology
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• v.30 no.4
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• pp.136-142
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• 2020

Crystallization of zinc crystalline glaze requires demanding conditions such as the formation of a nucleating agent and the amount of nucleating agent, and growth of crystalline. Zinc crystalline glaze is hard to utilize in the industry because of its narrow range of the firing temperature, and the crystallization's dependency on the quality of zinc. Stimulation of zinc crystallization and formation of frit enable zinc crystalline glaze to be reconstituted in a various range of firing schedules, leading to the development of a competitive industrial glaze.

• Journal of the Korean Ceramic Society
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• v.50 no.2
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• pp.116-121
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• 2013

Zinc crystal glaze has its limits in practical use of commercial glaze due to the controlling crystal. In order to overcome this limit, and to heighten the practical usage, this study is aimed to develop artificially controlling willemite ($Zn_2SiO_4$) zinc crystalline glaze. For this purpose, it has experimented with the effect of anatase form and rutile form using $TiO_2$ known as nucleating agent. In zinc glaze, adding $TiO_2$ resulted with anatase form becoming more effective at nucleating formation and growth of willemite than the rutile form. Furthermore, it turned out that using the $TiO_2$ - anatase form, with synthetic seeds (zinc silicate), the numbers and positions of crystals can be controlled artificially.

• Journal of the Korean Professional Engineers Association
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• v.23 no.6
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• pp.117-122
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• 1990

The effect of firing on the development of strength of china with maturing range of a series of glaze that gave no defect on firing was observed in an electrical furnace and oil-fired kiln. The body formular is as follows (equation omitted), and it was applied to a selected china body. Porcelain glaze formular is in the following. (equation omitted) The result obtained is sumarized as follows : (1) It was found that the strength of porcelain increases when the A1$_2$O$_3$ moles of the glaze increses, and the strength of porcelain decreases when the SiO$_2$ moles of glaze decreases at 3.9-5.9 moles, and increases again when the SiO$_2$ moles increases at 5.9-7.9 notes. (2) It was found the most safe glaze is No. 25 glaze.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.28 no.1
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• pp.38-43
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• 2018

Ceramic membrane has been widely used for water treatment due to its advantages of eco-friendly property and low energy consumption. However, high porosity of ceramic membrane higher than 40 % may cause a problem of strength, when it is applied to a water treatment module. In order to solve this problem, the strength of the membrane edge was improved by using the ceramic glaze. Four different glaze compositions for low temperature sintering was selected to minimize the deformation of the membrane microstructure. After coating with low temperature glaze, cracks were observed due to differences in thermal expansion coefficient between the membrane and glaze. Thus, the thermal expansion coefficient of glaze was controlled by addition of cordierite and petalite. As a results, the compressive strength of the ceramic membrane, which was coated with the optimized glaze composition, was increased from $27N/m^2$ to $117N/m^2$, indicating that the glaze coating can improve the disadvantages of the fragile ceramic membrane.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.24 no.2
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• pp.70-76
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• 2014

$Zn_2TiO_4$, using an anatase form of $TiO_2$ on zinc crystalline glaze, was shown as effective nuclear agent. Thus the effects on glaze were studied with synthesized $Zn_2TiO_4$ at low temperature. First, the chromophore elements were employed in synthesized $Zn_2TiO_4$ then add them in the zinc crystalline glaze. Crystal creation and development of color by $Zn_2TiO_4$ addition on the zinc crystalline glaze were more effective. Addition of $Zn_2TiO_4$, which is developed in low range temperature, is effected as zinc crystalline nuclear in the willemite glaze. When 5 wt% of synthesized $Zn_2TiO_4$ was added to the willemite glaze, nuclear creation increases and steadily retains. Therefore addition of respectively doped $Zn_2TiO_4$ with CoO, NiO, and CuO would increase doped effects in the glaze, various color willemite crystal were obtained.

• Journal of the Korean Ceramic Society
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• v.35 no.4
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• pp.378-384
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• 1998

We investigated the possibility of systemizing data for the colour gradation of classical ceramics by build-ing program and D-basing each data information in pottery field that has been fall behind in forming data be-cause of many variable and lacking of data system. In this study we manufactured $CoAl_2O_4$ stain that has stable spinel structure at high temperature and then mixed base glaze with stain for the additive per-centage of 0.5 , 1, 5, 10, 15 wt% In thie colouring of Lime base glaze with the wide ranged melting tem-perature the colour development of cobalt-blue sintered at $1250^{\circ}C$ is better than that of $1150^{\circ}C$ $1350^{\circ}C$ The experimental conditions and data are D-based simulated programming of computer. The result of -based data appeared to be more smoothed fusion-adherence in the Matt glaze range of Lime base glaze, The variation of colouring is not found when additive content of glaze is more than 5 wt% and the stable colour development of stain was shown at the content that RO, $R_2O$ percentage is high (the content that R2O3 per-centage is low)

• Journal of the Korean Ceramic Society
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• v.52 no.6
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• pp.508-513
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• 2015

In order to improve the hardness of commercial bone china, we attempted to control the glost firing temperature and apply a chemical strengthening process. When the glost firing time was longer or its temperature was higher than normal conditions, the hardness was improved by approximately 5%. The chemical strengthening process also enhanced the hardness of the glaze by more than 13% compared with bone china. It is believed that the enhancement of the hardness of the glaze was related to the development of residual compressive stress in the glaze due to 1) the increase in the calcium phosphate phase in the interface layer between the body and the glaze after firing, and 2) the increase of the $K^+$ concentration on the glaze surface during the chemical strengthening process.

• Journal of the Korean Ceramic Society
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• v.46 no.6
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• pp.548-553
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• 2009

This study is on the application of ceramic body and art glaze by using coal ash according to each wt%. Body color was turned red and dark as increasing coal ash contents in the body and art glaze because of the effect of noncombustible carbon in $Fe_2O_3$ and coal ash. Not only pore and black core were generated but also absorptance and shrinkage were increased as increasing coal ash contents. The glaze of coal ash 20 wt% showed blue absorption band, turned red band as increasing coal ash contents, $Al_2O_3\;to\;SiO_2$ ratio got lower and became mat because glaze is estranged from $Al_2O_3\;to\;SiO_2$ mol ratio 1:10 of transparent glaze as increasing coal ash contents. Glaze showed unstable dissolving condition in the more coal ash contents.

• Journal of the Korean Ceramic Society
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• v.43 no.7 s.290
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• pp.393-401
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• 2006

The development of Korean glaze originated from the development of ash glazes. Ash not only has strong solubility but also can shows the glaze a variety of different colors according to what the glaze has in it as the main component. In addition, it gives a feeling of lucidness and softness. For these reasons, there are a lot of needs for ash and many potters want to take advantage of ashes as glaze. But natural ashes have not been widely used as glaze primarily because it is relatively hard to find or manufacture. Considering the difficulty of finding or manufacturing natural ashes, this study aims to formulate synthetic ash which not only is available to the potters in general but also has the sam ε characteristics as the natural ashes. To achieve this aim, this study examines the characteristics of the pine tree ash, the main component of the glaze of celadon porcelains, and the red pepper stem ash, the main component of the brown glaze, both of which have been used by the Korean traditional potters. In this study, the alkaline component of the glaze. A important ingredient when the ashes are synthesized, was supplied by mixing of $Na_2CO_3$, Chungju limestone and rice straw ash. Furthermore, the synthetic ash, when it shows no change of pH in its composition rate of 6:2:2, was found to be usable as the most stable material. In conclusion, the formula which frits some raw $materials-Na_2CO_3$, Chungju limestone and rice straw ash-can duplicate the synthetic ash which is simila to the natural ash.

• Journal of the Korean Ceramic Society
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• v.49 no.1
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• pp.66-71
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• 2012

In ancient Goryeo celadon, the effect of the chemical composition and ionic state of Fe on the color was evaluated by Mossbauer spectroscopy and Design of Experiment (DOE) analysis. The ancient celadon pieces excavated from the kiln sites in GangJin and Buan areas were analyzed by Mssbauer spectroscopy, chromaticity, and DOE analysis. The color of celadon was found to be mainly determined by that of glaze since variations of $L^*$, $a^*$, and $b^*$ values for the body were much smaller than those for the glaze. As $Fe^{2+}$/$Fe^{3+}$ in glaze increases, $L^*$ value increases, whereas $a^*$/$b^*$ value decreases, which is well consistent with the result on the synthetic glaze. As the amount of titanium increases in the glaze, the $a^*$ and $b^*$ values decrease; on the other hand, the $L^*$ value increases, which is well consistent with the result on the synthetic glaze.