• Journal of the Korean Ceramic Society
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• v.44 no.10
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• pp.554-561
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• 2007

Synthesis and characterization of pigments by using $Fe_2O_3,\;CoO,\;Cr_2O_3\;and\;MnO_2$ were undertaken. The resulting pigments were characterized by using XRD, SEM, FT-IR and UV-Vis spectrophotometer. The color of glazed tiles containing 6 wt% pigment changed from dark green to black depending on the compositions of used materials. Pigments were calcined with mixed materials at $1350^{\circ}C$, and the dark green and dark brown color were obtained. Pigments were used to determine possible interactions between a pigment and a glaze.

• Journal of Industrial Technology
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• v.3
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• pp.65-68
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• 1983

There are chief concerns every ceramist must keep in mind when firing a single kiln : Being able to read and control the kilns temperature as the firing progresses and as the kiln cools after firing. Controlling the atmosphere of the kiln in order to create desired glaze and clay body effects. Getting the most efficient use from the fuel-the most heat possible from the least fuel possible. The more exactly, author can control these factors with some result.

• Journal of the Korean Ceramic Society
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• v.45 no.7
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• pp.401-404
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• 2008

Willemite ($Zn_2SiO_4$) are a wide range of applications such as a phosphor host and an important crystalline phase in glass ceramics, electrical insulators, glazes, and pigments. In this study, Willemite precursors were synthesized with zinc silicate gels from mixture of zinc nitrate solution and various sodium silicate solution by the geopolymer technique. To examine the crystallization behavior, precursors were have been monitored by the XRD. A pure willemite phase was obtained at $900^{\circ}C$. TEM investigations revealed that the sample with 50 nm particle size was obtained via heat-treated at $900^{\circ}C$ for W-3.

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

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.33 no.6
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• pp.234-243
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• 2023

Zinc crystals of ZnO and SiO₂ in glaze raw materials, developed according to composition and firing requirements, are preferred because of their high decorative properties. However, most zinc crystal glazes have a high firing temperature and a narrow firing temperature range, making it difficult to use them as commercial glazes in ceramics. Therefore, in this study, it was expected that the firing temperature of a typical zinc crystal glaze could be lowered to below 1270℃ by using the eutectic effect through mixing frit, the main raw material used in manufacturing zinc crystal glaze. As a result, not only was the formation temperature of zinc crystals lower in the mixed frit glaze, but also the firing temperature range was widened to 1230~1270℃, making it possible to develop a glaze that produces crystals stably. The firing temperature was lowered to 1230~1250℃ and the holding temperature during cooling was lowered to about 950℃, resulting in the development of an economically effective glaze. When using a combination of frit, it has been shown that the holding temperature during cooling affects the recrystallization of zinc crystals depending on the composition of the glaze, and the crystal structure can be adjusted at this time. Additionally, the amount and shape of crystals can be controlled by using a nucleating agent.

• Journal of the Korean Ceramic Society
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• v.46 no.3
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• pp.253-262
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• 2009

The purpose of this study is to find out optimum conditions for zinc crystalline glaze under variables of firing: maximum firing temperature, crystal growth temperature, temperature increasing speed, annealing speed, holding time at maximum temperature and holding time at crystal growth temperature. Ferro Frit3110, ZnO and Quartz were used as starting materials and tested by three component system. The best result of test was selected and extended to its vicinity as five glaze formulas. And then the specimens were experimented by variable firing conditions and analyzed by crystal appearance observation, XRD, FT-IR and Raman spectroscopy. In result, main crystal was willemite in the zinc glazes. Some gahnite was detected in specimens which were fired at $1230^{\circ}C$, $1250^{\circ}C$ and $1270^{\circ}C$, however gahnite was not identified at $1300^{\circ}C$. Optimum zinc crystalline glaze was gained by following 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.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.1
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• pp.160-168
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• 1998

In order to investigate the color variation and the solubility limit in wagnerites by metal ion substitution, wagnerite ($A_2XO_4Z$) was synthesized and then, substituted by coloring metal ions, especially $CO^{2+},Ni^{2+}$ and $Cu^{2+}$ ions. When calcium was replaced with Mg, Co, Ni and Cu divalent ions, solid solutions were formed with a limited solubility. Single phase wagnerites were synthesized by the substitution of Ca with Mg and Co, and their colors were white and purple, respectively. Substitutions with $Li^+$ were succeeded in the specific composition and the substitution of vanadium for $X^{5+}$ were attempted, resulting in the wagnerites of dark purple, dark gold and light yellow colors. The substitution of chlorine was, also, attmepted for the fluorine site.

• Journal of the Korean Ceramic Society
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• v.52 no.1
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• pp.41-47
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• 2015

Celadon shards from Gangjin and Buan were analyzed for their color, chemistry and microstructures. They exhibited similar chromatic characteristics in a $CIEL^*a^*b^*$ analysis. All of the glazes assessed showed comparable compositional areas, while the bodies from Gangjin shards had higher $RO_2$ concentrations. A high degree of similarity was also noted in the microstructures of the glaze and bodies from both regions. Anorthite crystals appeared in the glaze layer, and phase separation behavior developed around these crystals. This may have been caused by the glaze chemistry and the sintering process given the lengthy heating and cooling time. A Raman analysis indicated higher isolated $SiO_4$ unit ($Q_0$) values for the Buan samples. This can stem from the higher firing temperature or the longer sintering process.

• Journal of the Korean Ceramic Society
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• v.47 no.6
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• pp.608-612
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• 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
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• v.45 no.5
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• pp.256-262
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• 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.