• Journal of the Korean Ceramic Society
• /
• v.47 no.6
• /
• pp.608-612
• /
• 2010

Uvarovite Garnet is green pigment prepared by using $Cr_2O_3$, CaO and $SiO_2$ which are widely used in ceramic industry. The synthesis of above pigment was carried out by mixing $K_2Cr_2O_7$, $SiO_2$ and $CaCO_3$ as formulated and then firing at $1000{\sim}1200^{\circ}C$. To investigate the optimum synthesis condition of the Uvarovite Garnet. it was prepared by using CaO to replace $CaCO_3$, $CaF_2$ and $CaCl_2$. To get green brighter color, $Al^{3+}$ was substituted for $Cr^{3+}$. They were characterized by X-ray diffraction, UV-Vis spectroscopy, Raman spectroscopy and SEM analysis. When the pigments were applied to lime glazes (6 wt%), color parameters of Uvarovite Garnet showed the $L^*$=40.99, $a^*$=-16.23 and $b^*$=17.04.

• Journal of the Korean Ceramic Society
• /
• v.45 no.5
• /
• pp.268-275
• /
• 2008

In high temperature ceramic glazes, a stable range of pink-red colors producing $Cr_2O_3-SnO_2-CaO-SiO_2$ pigments are factored by Cassiterite and Malayaite relationship with $Cr_2O_3$. The experiment described the effect of $CrCl_3$ by adding $H_3BO_3$ as a mineralizer to increase the formation of Malayaite crystal, substituting $CrCl_3$ instead of $Cr_2O_3$ in pigment as a chromophore. Synthesized pigments were analyzed by XRD, FT-IR, Raman Spectroscop, UV and UV-vis. The result shows the differences in amount of crystal phases and oxidation state of Cr ion, which causes the color change. The melting point of $CrCl_3$ is lower than $Cr_2O_3$ which act as a mineralizer and makes the pigment synthesized in lower temperature at $1200^{\circ}C$. Holding 3 h firing at $900^{\circ}C$ where the synthesize forms shows better effect of Malayaite crystal phases and increasing engaged effect of $CrCl_3$ where the color pigmentation is more defined then in $Cr_2O_3$.

• Korean Journal of Materials Research
• /
• v.23 no.5
• /
• pp.286-292
• /
• 2013

Generally, the color gold has had a biased conception due to its traditional use. Thus, this bias has resulted in a lack of usage of golden glaze on ceramics and also a lack of extensive studies of such glazes. In this paper, optimum conditions and mechanism of formation of gold color crystallization glaze containing $Fe_2O_3$(hematite), which is developed for gold colors of ceramic glazes, were studied. Experimental result showed that there are pyroxene based on diopside and $TiO_2$ phase in the base of a crystallization glaze with a value of $TiO_2$ of 6 wt% confirmed by XRD and Raman Spectroscopy. When $Fe_2O_3$ was used as a colorant for the gold color, the $TiO_2$ peak became extinct and the intensity of the diopside peak was sharper. Feldspar of 60 wt%, talc of 20 wt% and limestone of 20 wt% were used as the starting materials and these were tested using a three component system. The best result of test was selected and extended to its vicinity as an experiment to determine $TiO_2$ and $Fe_2O_3$ contents. The glaze with $TiO_2$ of 6 wt% and $Fe_2O_3$ of 12 wt% addition showed stable pyroxene based diopside crystals and the development of gold color. This gold color was obtained with CIE-$L^*a^*b^*$ values of 51.27, 4.46, 16.15 (a grayish yellow brown color), which was gained using the following firing conditions: temperature increasing speed $5^{\circ}C$/min, holding for 1 h at $1280^{\circ}C$, annealing speed $3^{\circ}C$/min till $1100{\circ}C$, holding for 2 h at $1100{\circ}C$, and finally natural annealing.

• Journal of the Korean Ceramic Society
• /
• v.45 no.5
• /
• pp.256-262
• /
• 2008

$ZnAl_{1-x}\;Cr_xO_4$ solid solutions were synthesized as pink pigments with and without mineralizer. The pigments were examined to optimize color development conditions of temperature and $Cr_2O_3$ contents. The characteristics of synthesized pigments were analyzed by XRD, XPS, FT-IR and UV-vis spectrophotometer. While samples without mineralizer fired at $1300^{\circ}C$, showed $ZnAl_2O_4$ and $ZnCr_2O_4$ spinel in XRD analysis. While samples with mineralizer resulted in $ZnAl_2O_4$. As a results, the pigments show pink color and most effective pink color was obtained at X=0.15 and $1250^{\circ}C$ when mineralizer was used. The chromatic coordinates are $L^*$ 58.61 $a^*$ 24.48, and $b^*$ 9.60.

• Journal of the Korean Ceramic Society
• /
• v.36 no.4
• /
• pp.333-342
• /
• 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
• /
• v.43 no.10 s.293
• /
• pp.619-625
• /
• 2006

The study was intended to investigate production tools and conditions of oil spot following calculating optimal composition of oil spot tenmoku glaze which can be produced at 1250$\sim$l260$^{\circ}C$. Since oil spot is influenced by the viscosity of glaze, viscosity of various glazes fit for oil spot production was determined by an SciGlass 6.0-based calculating method. Applied amount and calcinating conditions of the resulting substance of oil spot, $Fe_2O_3$, were analyzed. As a result, the viscosity of the glaze durable at 1260$^{\circ}C$ was found to range from 4.2 to 4.4, natural cooling was used after oxidizing calcinations at 1260$^{\circ}C$ for an hour, and the best oil spot tenmoku was produced by the natural cooling process after 1 h calcinations at 1150$^{\circ}C$ in the middle of natural cooling. Also, the study showed that thickness of glaze was found to have an effect on the production of oil spot and resulting oil spot was filled mostly with $Fe_2O_3$.

• Journal of Conservation Science
• /
• v.26 no.3
• /
• pp.213-228
• /
• 2010

The composition of Chinese ceramic shards has been the subject of analysis in Europe, beginning in the 18th century, and in China from the 1950s. Scientific studies of traditional Korean shards commenced in the United States and Germany in the 1980s, and studies within Korea began in the 1990s. From analysis of a large systematically collected dataset, the composition of porcelain produced during the Kory. dynasty, including 21 celadon and 10 whiteware groups, was characterized and compared with that of Chinese ceramics. The average composition of the body and glaze of several shards (usually three to five) from each group was determined, enabling comparisons between groups. The results show that the majority of groups were derived from mica-quartz porcelain stone, which was commonly used in Yuezhou, Jingdezhen, and other southern Chinese kilns. The composition of glazes includes clay and flux components; the latter were typically wood ash and limestone, initially as burnt but later as crushed forms. The earliest of the Kangjin glazes contained substantially less titanium oxide than did the Yuezhou glazes, which were typically formulated from body material and wood ash. The present study provides a comparative framework for the growing number of analytical investigations associated with excavations occurring in Korea.

• Journal of the Korean Ceramic Society
• /
• v.43 no.7 s.290
• /
• pp.393-401
• /
• 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 Crystal Growth and Crystal Technology
• /
• v.27 no.5
• /
• pp.243-248
• /
• 2017

In this study copper glaze samples were prepared with varying amount of tin oxide, and the chromatic characteristics of glazes were explained on the results of spectrophotometric, crystalline phase, and microstructural analyses. The red color of copper glaze was dissipated with the addition of tin oxide and turned into achromatic color due to the decrease of CIEab values. Tin oxide homogeneously distributed in the glaze layer interfered with the red color generation coming from the growth of Cu nuclei, and formed an alloy with metal copper around bubbles. This resulted in the decrease of metal copper peak intensity with minor $Cu_2O$ peak. With the 3.79 % tin oxide addition the glaze was appeared as gray due to the black color CuO and Cassiterite $SnO_2$ phases.

• Journal of the Korean Ceramic Society
• /
• v.44 no.11
• /
• pp.639-644
• /
• 2007

Spinel pigments, developing black color in high temperature glazes at oxidation or reduction atmosphere, without CoO because of its high price were synthesized by solid solution method. Ten mixed compositions consisted of NiO, MnO, $Fe_2O_3 and $Mn_2O_3$ were fired at $1250^{\circ}C$ for 1h. The resulting pigments were characterized by using XRD, FT-IR, SEM and UV-vis spectrometer. Structure of the pigments are spinel and particles' shape are spherical or cubic. Glazed tiles containing 5 wt% pigments were fired at $1260^{\circ}C$ and $1240^{\circ}C$ in reduction atmosphere. Color in glazes were analyzed by UV-vis spectrometer. Colors of NiO 0.875 MnO $0.125{\cdot}Fe_2O_3$ $0.4875{\cdot}Cr_2O_3$ $0.50{\cdot}Mn_2O_3$ 0.0125 mole% and NiO 0.875 MnO $0.125{\cdot}Fe_2O_3$ $0.3875{\cdot}Cr_2O_3$ $0.50{\cdot}Mn_2O_3$ 0.1125 mole% in lime glaze showed black in oxidation, in reduction NiO 0.875 MnO $0.125{\cdot}Fe_2O_3$ $0.4875{\cdot}Cr_2O_3$ $0.50{\cdot}Mn_2O_3$ 0.0125 mole% and NiO 0.875 MnO $0.125{\cdot}Fe_2O_3$ $0.4375{\cdot}Cr_2O_3$ $0.55{\cdot}Mn_2O_3$ 0.0125 mole% showed black. In case of lime-barium glaze, NiO 0.875 MnO $0.125{\cdot}Fe_2O_3$ $0.3875{\cdot}Cr_2O_3$ $0.50{\cdot}Mn_2O_3$ 0.1125 mole%, NiO 0.975 MnO $0.075{\cdot}Fe_2O_3$ $0.4375{\cdot}Cr_2O_3$ $0.50{\cdot}Mn_2O_3$ 0.0625 mole% and NiO 0.925 MnO $0.075{\cdot}Fe_2O_3$ $0.4375{\cdot}Cr_2O_3$ $0.50{\cdot}Mn_2O_3$ 0.0625 mole% showed black color in oxidation and NiO 0.875 MnO $0.125{\cdot}Fe_2O_3$ $0.3875{\cdot}Cr_2O_3$ $0.50{\cdot}Mn_2O_3$ 0.1125 mole%, NiO 0.925 MnO $0.075{\cdot}Fe_2O_3$ $0.4375{\cdot}Cr_2O_3$ $0.50{\cdot}Mn_2O_3$ 0.0625 mole% and NiO 0.725 MnO $0.275{\cdot}Fe_2O_3$ $0.4375{\cdot}Cr_2O_3$ $0.50{\cdot}Mn_2O_3$ 0.0625 mole% showed black one in reduction.