Byung-Ha Lee

Synthesis of Cr-doped Y 2 O 3 -Al 2 O 3 Red Pigments and their Application

New inorganic red pigments based on Cr-doped Y₂O₃ and Al₂O₃ were synthesized by solid state method and characterization of their pigments were characterized by using XRD, FT-IR, SEM and UV-Vis spectrophotometer. The single perovskite phase revealed at 1450℃~1550 ℃ for 6 h due to using mineralizers. The color of pigment powders resulted out various red-shades depending on the compositions of used materials and temperatures. Glazed tiles painted with pigment powders showed red color in oxidation and reduction firing. The best red colour was obtained when the Cr₂O₃ was used 0.04 mole at 1450℃ for 6 h.

Sphene-Pink 안료에 미치는 CrCl₃의 영향

In high temperature ceramic glazes, a stable range of pink-red colors producing Cr₂O₃-SnO₂-CaO-SiO₂ pigments are factored by Cassiterite and Malayaite relationship with Cr2O₃. The experiment described the effect of CrCl₃ by adding H₃BO₃ as a mineralizer to increase the formation of Malayaite crystal, substituting CrCl₃ instead of Cr₂O₃ 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 CrCl₃ is lower than Cr₂O₃ which act as a mineralizer and makes the pigment synthesized in lower temperature at 1200℃. Holding 3 h firing at 900℃ where the synthesize forms shows better effect of Malayaite crystal phases and increasing engaged effect of CrCl₃ where the color pigmentation is more defined then in Cr₂O₃.In high temperature ceramic glazes, a stable range of pink-red colors producing pigments are factored by Cassiterite and Malayaite relationship with . The experiment described the effect of by adding as a mineralizer to increase the formation of Malayaite crystal, substituting instead of 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 is lower than which act as a mineralizer and makes the pigment synthesized in lower temperature at . Holding 3 h firing at where the synthesize forms shows better effect of Malayaite crystal phases and increasing engaged effect of where the color pigmentation is more defined then in .

Development of Black Color Spinel Pigment for High Temperature

This research studied the most suitable synthesis condition of mineral pigments of black spinel, which have a stable chromogenic characteristic also ata high temperature of 1400℃ (it is not currently producedin the country) to meet not only functionality of ceramics but also an individual’s aesthetic. It was synthesized by the plastic synthetic method on the basis of basic formation of Fe₂O₃, Cr₂O₃, Quartz, Kaolin, CoO, MnO₂, and plasticity was made at 1500℃, 1550℃, 1600℃, 1650℃. We researched the most suitable condition of plasticity and composition which make crystallization of spinel system and chromogenic characteristic close to black in every composition. And for the experiment of application to Zirconia, after adding synthesized pigments to Zirconia and plasticizing them, we analyzed their color and property of matters. The most suitable synthesis conditions of mineral pigments of black spinel system require composition of Fe₂O₃-32.01%, Cr₂O₃-30.47%, Quartz-9.66%, Kaolin-18.53%, CoO-3.71%, MnO₂-5.62% and condition of plasticity kept for 1 h at 1600℃. When we added pigments synthesized in this way to Zirconia with 5 wt% and plasticized them at 1410℃, the result was that the degree of strength-32.6 ㎏f/㎟, absorptance-0.108%, luminosity-L*: 37.54, color-a*:1.31, b*:2.61 and their use suited for artificial jewelry or decoration Zirconia goods.

Fe₂O₃-CoO-Cr₂O₃-MnO₂계 안료의 합성 및 유약에서의 발색

Synthesis and characterization of pigments by using 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 , and the dark green and dark brown color were obtained. Pigments were used to determine possible interactions between a pigment and a glaze.Synthesis and characterization of pigments by using Fe₂O₃, CoO, Cr₂O₃ and MnO₂ 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℃, and the dark green and dark brown color were obtained. Pigments were used to determine possible interactions between a pigment and a glaze.

Ceramics Body Development Using Waste Whiteware

Ceramics manufacturers in the nation produced more than 5000 tons of ceramics wastes a year increasing industrial waste quantity: However, almost no researches were made to reduce environmental pollution and to recycle waste ware. In this study, white ware scraps that were produced at Icheon, Gyeonggi-do were recycled to make use of them as raw materials of ceramics body and to develop new ceramics body that had economic advantages and good quality. The findings showed that the addition of waste ware had limit of 20 wt% considering molding. The addition of waste ware of 20 wt% to white ware lowered baking temperature of the white ware that was added by waste ware of 20 wt% by 30 ℃ than existing white ware, and property values were good, for instance, porosity of 3% in average and water absorptivity of 2% in average, and the bending strength recorded more than 800 kgf/㎠ to be higher than that of existing white ware being sold in market. The waste ware could be used to produce new ware body and to recycle resources and to solve environmental problems caused by burial and to improve property of ceramics and to save transportation costs as well as baking costs.

Colouring Effect of Malayaite Formation and Synthesis Sphene-Pink Pigment

This paper described the study of a sphene-pink pigment based on Cr₂O₃-SnO₂-CaO-SiO₂ system exhibits stable pink-red color at high temperature. This study is focused on the optimization of the synthesis parameter such as temperature and holding time for the formation the Malayaite crystal. Malayaite crystal is sensitively influenced by the synthesizing temperature, maintaining time and contents of substituting chromium. The crystal phases formed at different temperatures exhibits various color. The optimum temperature is suggested at 1300℃ for 2 h and substituting contents of Cr for Sn is 0.01 mole. The maximum substituting contents is 0.02 mole based on analysis results by XRD, FT-IR, SEM and UV-vis.

Synthesis of Cobalt Oxide Free Black Color Spinel Pigment

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, Fe₂O₃, Cr₂O₃ and Mn₂O₃ were fired at 1250℃ 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℃ and 1240℃ in reduction atmosphere. Color in glazes were analyzed by UV-vis spectrometer. Colors of NiO 0.875ㆍMnO 0.125ㆍFe₂O₃ 0.4875ㆍCr₂O₃ 0.50ㆍMn₂O₃ 0.0125 mole% and NiO 0.875ㆍMnO 0.125ㆍFe₂O₃ 0.3875ㆍCr₂O₃ 0.50ㆍMn₂O₃ 0.1125 mole% in lime glaze showed black in oxidation, in reduction NiO 0.875ㆍMnO 0.125ㆍFe₂O₃ 0.4875ㆍCr₂O₃ 0.50ㆍMn₂O₃ 0.0125 mole% and NiO 0.875ㆍMnO 0.125ㆍFe₂O₃ 0.4375ㆍCr₂O₃ 0.55ㆍMn₂O₃ 0.0125 mole% showed black. In case of lime-barium glaze, NiO 0.875ㆍMnO 0.125ㆍFe₂O₃ 0.3875ㆍCr₂O₃ 0.50ㆍMn₂O₃ 0.1125 mole%, NiO 0.975ㆍMnO 0.075ㆍFe₂O₃ 0.4375ㆍCr₂O₃ 0.50ㆍMn₂O₃ 0.0625 mole% and NiO 0.925ㆍMnO 0.075ㆍFe₂O₃ 0.4375ㆍCr₂O₃ 0.50ㆍMn₂O₃ 0.0625 mole% showed black color in oxidation and NiO 0.875ㆍMnO 0.125ㆍFe₂O₃ 0.3875ㆍCr₂O₃ 0.50ㆍMn₂O₃ 0.1125 mole%, NiO 0.925ㆍMnO 0.075ㆍFe₂O₃ 0.4375ㆍCr₂O₃ 0.50ㆍMn₂O₃ 0.0625 mole% and NiO 0.725ㆍMnO 0.275ㆍFe₂O₃ 0.4375ㆍCr₂O₃ 0.50ㆍMn₂O₃ 0.0625 mole% showed black one in reduction.

유적 천목의 유적 발생 구조

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 1250~1260 ℃. 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, Fe₂O₃, were analyzed. As a result, the viscosity of the glaze durable at 1260 ℃ was found to range from 4.2 to 4.4, natural cooling was used after oxidizing calcinations at 1260 ℃ for an hour, and the best oil spot tenmoku was produced by the natural cooling process after 1 h calcinations at 1150 ℃ 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 Fe₂O₃.

Bone Body Production and Red Color Body Development Using the Bone Body

For the purpose of development of red color stain body, bone body which can be fired at 1180 ℃ and has a higher degree of whiteness and transmission was developed and a property experiment depending on the content of Fe₂O₃ was performed. For manufacturing this body, 9% addition of bone ash to commercialized white body resulted in the best whiteness and proper physical characteristics. In an experiment of oxidized iron addition using this body as a basis, red color stain body fired up to 1150 ℃ following the addition of 6% oxidized iron showed physical characteristics such as 5.4R color closer to theory color, 0.08% water absorption rate, 9.1% shrinkage, and 1861 ㎏f/㎠ bending strength, which implies that this body is suitable for red color stain body.

A Synthesis of Mullite-Cordierite Composite Powders by Solution-Polymerization Route Based on Polyvinyl Alcohol

Mullite와 cordierite는 우수한 열적, 화학적 특성을 나타내는 안정된 산화물로서 다양한 구조재료 및 전자재료에 사용되어지고 있으나, mullite의 경우 내열충격성이, cordierite 의 경우 고온강도가 떨어지는 단점이 있다. 이와 같은 단점을 서로 보완하기 위한 mullite-cordierite 복합체에 대한 연구가 진행되고 있다. 본 연구에서는 fused silica, aluminium nitrate, magnesium nitrate와 PVA의 혼합을 이용한 solution-polymerization 합성법에 의해, mullite-cordierite 복합분말을 합성하고 생성상 및 결정성, 밀도 및 비표면적 등의 특성을 분석하였다. 그 결과, 본 실험의 모든 조선에서 있어서 1300℃로 열처리 하였을 경우, mullite와 cordierite의 상이 공존하는 복합분말이 생성되는 것을 확인할 수 있었다. 이 mullite-cordierite 복합분말을 planetary milli로 1시간 분쇄하였을 때 비표면적은 약 20 ㎡/g로서 미립의 분말이 확인되어졌고, 분쇄시간의 증가에 따라 4시간에서는 23㎡/g, 8시간에서는 24㎡/g로 비표면적이 증가하였다.