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동화자기는 12세기 고려시대에 산화구리 안료를 1200℃ 이상의 높은 온도에서 발색시켜 제조한 도자기로서 기법과 시기 면에서 중국보다 앞서 있는 우수한 전통과학기술이다. 본 연구에서는 동화의 발색에 영향을 미치는 요인들을 분석하고 안정적인 동화 색상 구현을 위한 조성과 공정기술을 개발하고자 하였다. 동화유약의 기본유약 조성을 고정하고 발색산화물을 CuO, Cu2O로 달리하였다. 또한 CuO의 환원과정에 영향을 미치는 것으로 알려진 산화주석(SnO2)의 첨가량을 변화시켜 색상 변화를 관찰하였다. 또한 소결공정 중 Air와 LPG의 혼합비 (Air 5ℓ/min, LPG 0-0.7ℓ/min)를 변화시켜 환원분위기에 따른 동화유약의 발색을 관찰하였다. 그 결과 산화구리(Ⅱ)(CuO) 0.5wt%에서 환원분위기 LPG:0.5ℓ/min의 Munsell color 6R 4.7/2로 채도는 낮았지만, 광택도(glossiness) 39.4GU와 표면조도(roughness) 3.97㎛를 고려할 때, 안정적인 동화유약이라고 판단되었다. LPG:0.7ℓ/min에서도 산화구리(Ⅱ) 0.5wt%의 광택도 58.1GU와 표면조도 2.15㎛를 고려할 때, 매끄러운 유약표면으로 판단되었다. 산화구리(Ⅱ)과 산화주석의 혼합에 따른 동화유약의 발색은 환원분위기에서 유약의 발색이 Gray 톤으로 변하는 산화주석의 특성에 의해 dull 톤의 YR계열로 동화유약으로의 활용이 적합하지 않은 것으로 판단되었다. 산화구리(Ⅰ) 첨가량에 따른 동화유약의 발색은 환원분위기LPG:0.5ℓ/min과 LPG:0.7ℓ/min에서 가장 R계열의 발색을 나타냈지만, 구리(Cu) 이온의 휘발성에 의해 기포와 끊음 현상이 발색하였고, 그 결과 낮은 광택도와 매우 거친 유약 표면을 나타냈다.


Copper-red porcelain was a type of porcelain, whose color was developed by baking oxidised copper on 1200℃ or a higher temperature, produced in 12th Century, during the Goryeo dynasty. It showed the outstanding traditional porcelain technology of the Goryeo dynasty, which was faster and more advanced than Chinese in the respect of time and technology. This study aims to analysing factors influencing in color development of copper-red, and developing composition and process technology for materialising stable development of copper-red color. To do so, the coloring oxides were switched to CuO and Cu2O while the basic composition of copper-red glaze was fixed. In addition, the amount of SnO2, known to affect the deoxidisation process of CuO, was varied and the changes of color were observed. Furthermore, the mixture ratio of the air and LPG (Air 5ℓ/min, LPG 0-0.7ℓ/min) was changed to observe color development of copper-red glaze according to reducing atmosphere. As a result, in 0.5wt% of CuO, Munsell color of the reducing atmosphere LPG:0.5ℓ/min was low in Chroma by 6R 4.7/2, however considering the glossiness of 39.4(GU) and the roughness of 3.97㎛, it was found to be a stable copper-red glaze. In LPG:0.7ℓ/min, considering the glossiness of 58.1GU and the roughness of 2.15㎛ in 0.5wt% of CuO, it was found that the surface of glaze was slick. Regarding the color development of copper-red glaze according to the mixture of CuO and SnO2, due to the trait of SnO2 which developed the color of glaze into the grayish tone in the reducing atmosphere, it turned into YR group of dull tone. It indicated that it was not suitable to be utilised for copper-red glaze. Regarding the color development of copper-red glaze according to the amount of Cu2O, it showed the brightest R group at LPG: 0.5ℓ/min and LPG: 0.7ℓ/min, however due to the volatility of copper ion, bubbling and boiling occurred, so that the glossiness was low and the surface of glaze was substantially rough.