• 보존과학회지
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• 제36권4호
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• pp.275-283
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• 2020

Iron oxides are the essential coloring oxides in traditional ceramic glazes. However, when Fe is involved in the coloration in the form of ions or colloids in glazes with low Fe content, it is difficult to identify the iron oxide phases. Generally, in many these glazes, Ca-rich minerals are observed by X-ray diffraction (XRD) or microscopic images, owing to their devitrification by the high Ca content. This study attempts to elucidate the correlation between the crystalline structure and coloration in the glazes while mainly focusing on neoformed Ca-rich minerals and Fe content. An experimental firing was carried out to produce tree ash glazes, with pine tree ash and Buyeo feldspar. In the case of oxidation glazes, the scanning electron microscopy (SEM) images and XRD patterns did not exhibit any Ca-rich crystals, and all the visible light reflectance spectra lines exhibited a similar shape. In contrast, the reduction glazes divided into blue glazes and other colored glazes according to the shapes of their reflectance spectra. It was confirmed that the influence of Ca-rich minerals on the glaze color was more pronounced than the blue color of the reduction glazes when the Ca and feldspar contents were sufficiently high and low, respectively, to form wollastonite. As the Ca content increased and the elemental composition of the reduction glazes changed, the neoformation of the Ca-rich minerals, such as wollastonite, anorthite, diopside, and akermanite was sequentially observed.

• 한국세라믹학회지
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• 제13권3호
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• pp.3-12
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• 1976

The corelation between surface tensions and surface appearances of SK O5a opaque glazes for earthen wares were investigated. The surface tension values were theoretically calculated by using Dietzel's factors of constituent oxides of glaze. The surface appearances of glazes, especially the pinhole phenomena were strongly effected by the surface tension values showing the following general tendencies: (1) In the range of 305±3 dynes/cm of surface tensions, glazes showed almost no pjnholes. (2) In the range of surface tensions less than 300 dynes/cm, the large numbers of small pinholes or eggshell textures were observed. (3) In the range of surface tensions higher than 310 dynes/cm, large and deep pinholes were observed. (4) The contact angles of glazes on the wall tile body substrate are in the good proportional agreement with the surface tension values calculated by Dietzel's factors.

• 한국결정성장학회지
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• 제29권6호
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• pp.372-378
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• 2019

산화구리를 함유하는 전통 세라믹 유약은 황색포도상구균과 대장균에 대해 항균활성을 나타낸다. 환원 분위기에 소결한 모든 시편들은 황색포도상구균과 대장균에 대해 항균활성을 나타내나 산화분위기에서 소결한 일부 시편들만 황색포도상구균과 대장균에 대해 항균활성을 나타내었다. 산화구리를 함유하는 전통 세라믹 유약의 항균기작을 설명하기 위해 유약의 결정상, 미세구조, 이온용출, 표면 제타전위 분석을 실시하였다. 환원 분위기에서 소결한 시편들은 유약층에 Cu 입자들이 형성되는 것을 확인할 수 있다. Cu 용출량은 전체적으로 0.05 ppm 이하이며 가장 많이 용출되는 이온은 Ca 이었다. 산화구리를 3 wt.% 이상 첨가한 모든 시편들은 높은 음극의 표면 제타전위를 나타내었다. 세라믹 유약의 항균활성은 일반적으로 용출되는 양이온들과 연관되어 보이나 산화분위기에서 소결한 시편들의 대장균에 대한 항균활성은 직접적인 연관성이 나타나지 않는다. 세라믹 유약 시편의 표면 제타전위가 이온용출과 더불어 대장균에 대한 항균활성에 보조적 기여를 하는 것으로 보인다.

• 한국재료학회지
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• 제9권2호
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• pp.181-187
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• 1999

In this study, the effect of residual stress on mechanical strength was investigated with 1 kind of whiteware body and 4 kinds of glazes which are produced in succeeding ceramic art place. Using dipping method, the body was coated for different times in order to manipulate the coating thickness and sintered in the different temperatures ($1200^{\circ}C$, $1250^{\circ}C$, $1300^{\circ}C$, $1350^{\circ}C$) for two thus hours. The sintered bodies were characterized by XRD, EPMA, FEM and UTM in order to study the forming of reaction layer between body and glazes, residual stresses and the effects of residual stresses on mechanical strength of pottery. At $1300{\circ}C$, we obtained maximum density and mechanical strength. By the finite element method, the residual stresses in surface of body were minimum in specific thickness of glazes and the mechanical strength of body in that thickness of glazes showed maximum when the firing temperature was settled.

• 대한화학회지
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• 제7권2호
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• pp.144-152
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• 1963

브리스톨釉藥을 콘 5, 8, 11 番으로 燒成했을때 나타나는 狀態에 對한 組成變化와 粒度의 京鄕을 硏究하여, 밝은 半艶消 또는 艶消釉藥을 얻을 수 있었다. 卽 各 釉藥에 對한 熱成範圍, 曲强度 및 光澤, 平滑性, 乳白度, Eggshelling, 龜裂, Pinholing, Crawling 等에 對한 因子를 決定하므로서 얼마나, 珪酸, 알카리, 石灰를 變化시켜 實際 使用可能한 良好한 釉藥을 얻었다. 製造된 브리스톨釉藥은 最低 콘 5番부터 11번 또는 그 以上에서 긴 熟成範圍를 나타냈다. Crawling의 傾向에 있어서는 ZnO 量이 增加될때 特히 甚했으나, $Al_2O_4:\;SiO_2$의 比가 크고 ZnO 量이 많을때 乳白度가 顯著하였다. 釉藥의 粒子를 가늘게 하면 熱成이 잘되나 微粒이면 Crawling이 커진다. 釉藥두께를 增加해도 Crawling 傾向이 커진다.

• 한국세라믹학회지
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• 제52권3호
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• pp.197-203
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• 2015

The colorization of $Zn_2SiO_4$ crystal glazes was investigated by adding nucleating seeds with various coloring agents. The addition of color fixing agents such as $Fe_2O_3$, $MnO_2$, and NiO with seeds caused changes in the colors of glazes. The crystallinity and crystal size were dependent on glaze composition and firing schedules. By controlling coloring agents and firing schedules, it was possible to create various colors and sizes of crystals in a zinc-based crystalline glaze.

• 한국세라믹학회지
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• 제52권3호
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• pp.186-191
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• 2015

Tribological properties of whiteware with various transparent glazes, which have different composition and microstructure, were investigated. The wear resistance and friction behavior of the glazed whiteware are a very important aspect if the whiteware is used as tableware and for sanitation purposes. Generally, the wear property is influenced by the microstructure and surface morphology of the material. The whiteware specimens with two kinds of transparent glazes were fabricated by using the commercially available porcelain body. Furthermore, the commercial tableware, such as bone china, and traditional tableware were also examined as reference materials. All of the specimens showed that different pore structures might affect the mechanical and tribological properties. It seems that the wear resistance of whiteware is substantially related to the pore size and distribution of glaze rather than the hardness value of the specimen.

• 보존과학회지
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• 제35권2호
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• pp.117-129
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• 2019

신안선에서 발견된 흑유자 중 자주요계, 차양요, 홍당요 등 3곳으로 분류된 6점의 유약에 대해 과학적 분석을 실시하였다. 홍당요는 유약 두께가 얇고 자화가 거의 이루어지지 않았다는 점에서 큰 차이를 보였다. 차양요와 자주요계 흑유자의 경우 단면상으로는 서로 공통점이 확인되었으나 라만 매핑 이미지를 통해 자철석의 분포 범위에서 차이가 있는 것으로 확인되었다. 이러한 차이가 나타나는 원인과 흑유자의 유약 형성 조건을 알아보고자 실시한 소성 실험 결과, 발색제로 사용된 적철석($Fe_2O_3$)은 $1250^{\circ}C$ 보다 높게 소성될 때 자철석($Fe_3O_4$)으로 변하여 흑색을 띠는 것으로 나타났다. 따라서 홍당요 흑유자는 약 $1200^{\circ}C$, 자주요계와 차양요 흑유자는 $1250{\sim}1300^{\circ}C$에서 소성하였을 것으로 추정하였다. 다만 고대 가마의 소성 특성을 고려할 때 자철석의 영역이 유약 표면까지 확장될 수 있을 정도로 오래 소성되었을 가능성도 배제할 수 없다. 향후 흑유자 유약에 대한 라만 스펙트럼 및 매핑 이미지의 데이터베이스 구축과 더불어 추가적인 실험이 이루어진다면 흑유자의 제작 조건을 규명하는 데 도움이 될 것으로 기대된다.

• 한국세라믹학회지
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• 제17권4호
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• pp.213-216
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• 1980

A glass-ceramics material of composition %SiO_2$: 38.50, $Al_2O_3$: 26.00, $Na_2O$: 18.00, CaO: 6.00, MgO: 4.00, $TiO_2$: 7.50 was strengthened by coating a series of glazes$(SiO_2-B_2O_3-Al_2O_3-CaO-PbO-Na_2O-)$, which has lower thermal expansion coefficient than that of the glass-ceramics. The thermal expansion coefficient of the glazes ranges $80~90{\times}10^{-7}$cm/cm/$^{\circ}C$, whereas that of the glass-ceramics is $115{\times}10^{-7}$cm/cm/$^{\circ}C$. The glass-ceramics was identified to be composed of nepheline, carnegieite low form, and meta sodium silicate crystal by X-ray diffraction phase analysis. The glaze, having lower melting point and appropriate thermal expansion coefficient, was tried to be stable and good at secondary heat treatment.

• Conservation and Restoration of Cultural Heritage
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• 제1권1호
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• pp.39-48
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• 2012

The first twenty-five years of scientific study within Korea on Korean traditional ceramics has been characterized as a bridging effort to understand the rich field of artistic ceramic masterpieces on one hand with analytic results gained from mounds of broken shards and kiln wastes on the other. First shard pieces were collected directly from the waste mounds, but most of the analyzed shards were provided by art historians and museum staffs directly involved in systematic excavations. The scientific study is viewed as one of many complimentary ways in learning about the multi-faceted ceramics culture, ultimately connecting human spirits and endeavors from the past to the present to the future. About 1350 pieces of analyzed shards have been so far collected and organized according to the production location and time period. From the experimental results of the analysis, the compositional and microstructural characteristics of bodies and glazes have been deduced for many kiln sites of Goryeo and Joseon dynasties. Except for a few local kilns, porcelain stone was used as body material in both dynasties. The principle of mixing a clay component with a flux material was used in Korean glazes as was in China. The clay component different from body clay was often used early on. In Gangjin a porcelain material appropriate for whiteware body was mixed for celadon glaze, and in Joseon Gwangju kilns glaze stone was chief clay material. The use of wood ash persisted in Korea even in making buncheong glazes, but in Joseon whitewares burnt lime and eventually crushed lime were used as flux material.