• Korean Journal of Materials Research
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• v.24 no.7
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• pp.363-369
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• 2014

This is the study on diffusion of ceramic body oxide compounds to glaze. For ceramic bodies, no ferrous oxides contain white ware, celadon, and 3 wt% iron oxides contained white ware was used in this experiment. These ceramic bodies were glazed by transparency glaze, iron oxides contained glaze, and glaze made by pine tree ash that treated in 1240 degree, under reduction condition for an hour. An electron probe microanalyzer(EPMA) was used to study diffusion of oxides and to calculate distance of ceramics bodies. As a result, only iron oxide and magnesium oxide from the body diffused to glaze, and also made a band which shown very thin layer of iron oxide and magnesium oxide between the body and glaze. The densest band of iron oxide formed 100 to $150{\mu}m$ in the glaze, and the densest band of magnesium oxide was found 50 to $100{\mu}m$ in the glaze. Therefore, it could be concluded that iron oxide in the body is diffused to the glaze and it affects the color of glaze, even though iron oxide exists in the glaze. Furthermore, the thickness of the glaze has an effect on the color of celadon.

• Journal of the Korean Ceramic Society
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• v.36 no.4
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• pp.333-342
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• 1999

This research was performed to investigate how the basic glaze change affected colour development at high temperature with a stable colorant (spinel structure CoAl2O4 pigment) The compounded pigment which is widely used for porcelain was also tested for the basic glazes adaptability. The data from the test were recorded in a computer data-base program. Therefore could be easily used in the study related with a pottery field. CoO : Al2O3 system spinel pigment of barium glaze lime glaze zinc glaze lead glaze and talc glaze were chosen for this study. The colors of Cobalt blue bright blue, blue purple were seen at the wave lengths of 455-480nm at the firing temperature of 1250$^{\circ}C$. Stable color were obtained from lime glaze bar-ium glaze zinc glaze. All the information in the database were used to examine all the possible result of the test in the study of porcelain. When the test results database were examined in all temperature ranges the lack of adhesion with the pigment occurred at the temperature of 1150$^{\circ}C$. The lack of adhesion is seen due to vaporization of the lead glaze.

• Journal of the Korean Ceramic Society
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• v.48 no.2
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• pp.121-126
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• 2011

The study investigates the effects of a body that influences the nucleation and growth of crystal by experiment the application of zinc crystalline glaze to five of the most favorably used kinds of bodies sold in the market. As a result, in all bodies used in the test, willemite crystal is appeared on the surface and in the case of white porcelain, super white and white porcelain sculpture clay, beautiful crystals is developed. The reason that crystal does not grow and trickle down by sticking to the body in celadon clay and Sanchung clay is the large surface tension of glaze by ingredient CaO which is more often present compared to other bodies. In glaze, the ingredients $Al_2O_3$ and RO greatly influences the surface tension, and adhesion of the glaze and the body is completed by the glaze's power to stick, which is determined by the reaction of both the glaze and the body. However, in the case of Sanchung clay, the CaO in body reacts to the glaze, and glaze, on Sanchung clay, has tendency to run more compared with other bodies. It is supposed that this mechanism influences the growth of willemite crystal and the glaze's adhesion to the body.

• Journal of the Korean Ceramic Society
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• v.47 no.6
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• pp.598-602
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• 2010

When metal oxides are added into crystalline glaze, colors of glaze and crystals are similar as colorants generally. But the case of NiO in zinc crystalline glaze is different from general color development. When NiO is added to zinc crystalline glaze it can develop two or three colors. The active use of color development mechanism by adding NiO to the zinc crystalline glaze to control color of the base glaze and crystal with stability is investigated. This report is expected to contribute to the ceramic industry in improving application of zinc crystalline glaze. For the experiment of NiO, the quantity of NiO additives is changed to the base glaze for the most adequate formation of willemite crystal from previous research and firing condition: temperature increasing speed $5^{\circ}C/min$, holding 1 h at $1270^{\circ}C$, annealing speed $3^{\circ}C/min$ till $1170^{\circ}C$, holding 2 h at $1170^{\circ}C$ then naturally annealed. The samples are characterized by X-ray diffraction (XRD), UV-vis, and Micro-Raman. The result of the procedure as follows; Ni substitutes for Zn ion then glaze develops blue willemite crystals, as if cobalt is used, on brown glaze base. When NiO quantity is increased to over 5 wt%, willemite size is decreased, and the density of the crystal is increased, at the same time $Ni_2SiO_4$ (olivine) phase, the second phase, has been developed. The excessive NiO is reacted with silicate in the glass then developed green $Ni_2SiO_4$ (olivine), and quantity of $Ni_2SiO_4$ (olivine) is increased as quantity of willemite is decreased. It is proved to create three colors, blue, brown and green by controlling the quantity of NiO to the zinc crystalline glaze and it will improve the multiple use of colors to the ceramic design.

• Journal of the Korean Ceramic Society
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• v.55 no.3
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• pp.299-306
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• 2018

In order to improve the hardness of commercial bone china, we suggested a chemical strengthening process and new glaze for its process. New glaze contained about two times more $Na_2O$ and $Al_2O_3$ and had a higher transition temperature than that of commercial frit. Chemical strengthening enhanced the hardness of the new glaze-coated bone china by over 30% compared to that of commercial product. The change of glaze composition influenced potassium ion diffusion distance and depth of strengthened layer during chemical treatment. After chemical strengthening of new glaze-coated bone china, the residual compressive stress inside the glaze was measured and found to be greater than 160 MPa.

• The Journal of Korean Academy of Prosthodontics
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• v.29 no.3
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• pp.87-99
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• 1991

The effect of oven firing on the color stability and surface texture of extrinsic stains used characterization and color modification of metal cermic restoration were studied by comparing different temperatures and techniques. They were autoglaze technique, applied glaze technique, two step low-fusing glaze technique and one step low-fusing glaze technique. Autoglaze technique and applied glaze technique were air-fired to manufacturer's recommended temperature. Two step low-fusing glaze technique is separated staining and overglazing. Thin slurry of stain powder were air-fired to $1500^{\circ}F$, Overglaze powder powder was then mixed with seam medium and air-fired to $170^{\circ}F$. One step low-fusing glaze technique is combined staining and overglazing. Thin slurry of stain and glaze powder were air-fired to $170^{\circ}F$. The obtained results were as fellows. 1. Slightly significant color differences by colorimeter were found between different stain application and fusion techniques(P<0.05). 2. Two step low-fusing glaze method showed the most rough surface, especially ceramco orage stain(P<0.05). 3. Surface roughness increased gradually in order of autoglaze, applied glaze, one step low-fusing glaze but they were not significantly different(P<0.05). 4. When two step low-fusing glaze was applied, both color measurement and surface texture were sinificantly different from other groups(P<0.05).

• Journal of the Korean Ceramic Society
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• v.13 no.2
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• pp.17-23
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• 1976

The study is an attempt to prepare the raw graze can replace the lead glaze that has been used for a long time as Korean Kimchi-jars. 1) The batch of the glaze that show the similar properties and appearance of lead-glaze were 40% of Yongin or Anseong Yakto, 40% of Ash and 20% of Anhydrous-Colemanite. It's Seger Formula was {0.86 CaO 0.02 MgO 0.12 KNaO} {0.26 Al2O3 0.0007 Fe2O3} 0.92 SiO2 0.3 B2O3 2) The firing temperature of selected glaze was 950-1050℃. 3) As the content of anhydrous-Colemanite was increased, the thermal expansion coefficient was decreased. 4) The color of leadless raw glaze was translucent light yellow. It was possible to obtain the same color as lead glaze by Fe2O3 and MnO2.

• Journal of the Korean Ceramic Society
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• v.53 no.5
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• pp.535-540
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• 2016

Effects of compositions and sintering conditions on glaze properties are shown in the diagram constructed by using the unity molecular formula (UMF) method in this study. Glossy characteristics of glaze were clearly differentiated by compositional area in the diagram and sintering process. As alumina and silica contents were increased, texture of the glaze became rough and opaque, akin to having been devitrified or underfired. The correlation between glossiness and surface roughness was found to be non-linear and inversely proportionate. Crystalline phases formed in the glaze were also influenced by the compositional area. Due to the high concentration of CaO, anorthite and wollastonite were formed depending on the compositions. Hardness was increased with an increase of alumina and silica concentrations in the glaze.

• Korean Journal of Materials Research
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• v.23 no.7
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• pp.399-403
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• 2013

The purpose of this study is to investigate the coloration characteristics by identifying the factor affecting red coloration of copper red glaze in traditional Korean ceramics. This study analyzed the characteristics of the reduction-fired copper red glaze by using XRD, Raman spectroscopy, EDX and UV-vis spectroscopy. As a result of XRD analysis, the glaze completely melted and amorphous glass appeared overall, and the characteristic peak of metal Cu was shown together. In addition, as a result of Raman analysis, the characteristic bands of CuO and $Cu_2O$ were shown together. The distribution of component elements was observed by EDX. As a result, copper(Cu) were distributed throughout the glaze. Thus, it was shown that copper red glaze appeared the best red coloration because metal Cu, CuO and $Cu_2O$ evenly existed throughout glaze in particle colloidal state. The chroma value of the copper red glaze was CIE $L^*$ 30.07, $a^*$ 13.65, $b^*$ 3.72. Wine-Red Solution was shown by Dark Graish Red coloration.

• Journal of the Korean Ceramic Society
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• v.41 no.2
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• pp.158-164
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• 2004

This study is to analyze the characteristics of typical Korean wood ashes from twelve trees, oak tree needles and pine bark, which are common in the area, and to suggest their applications in ash glaze making. The chemical analysis of the ashes shows that the main component of wood ash is CaO while wood bark ash consists of $SiO_2$, and leaf ash consists of CaO and $SiO_2$. The results of the study are as follows: Ashes made from the wood of Acasia, Popular and Jujube contained relatively high amounts of Fe$_2$ $O_3$ and MgO compared to other tree ashes. The ashes had yellowish green color glaze. From the result of W analysis they presented the highest chroma. Therefore these ashes are good for making transparent glaze. From the result of W analysis Grapevine, pear and oak wood ashes containing the highest amounts of Fe$_2$ $O_3$, MgO, P$_2$O$\_$5/ and MnO presented yellowish green color glaze compared to other ashes are suitable for making opaque glazes because of their showing stable and opacity phenomena. Pine tree, Platanus and Zelkova wood ashes consist of high amounts of CaO and P$_2$O$\_$5/ compared to other tree ashes. So they showed the most vivid and bluish green color glaze among 12 ashes. Therefore, they would make a good celadon glaze. Birch, oak and chestnut tree ashes have high content or MnO which affects on glaze color with small amount. These ashes presented yellowish green color not as much strong as Acacia ash, Poplar ash, Jujube tree ash. These are good for Irabo glaze.