논문 상세보기
pp.233-239
We collected Seokganju minerals (regions in Gyeryong Mountain, Sangsin-ri, Banpo-myeon, GongjuChungcheongnam-province), which were used as natural color pigments for grayish-blue during the 15th~16th centuries of theJoseon era, and investigated their crystallographic features to develop a black pigment having a spinel structure. By a Ramananalysis, the color of Seokganju under transparent glaze as a pigment for painting was black because hematite (Fe2O3) inSeokganju was converted to magnetite (Fe3O4) However, Seokganju into the transparent glaze as a pigment was brown becauseof hematite (Fe2O3) and small amounts of maghemite (γ-Fe2O3) in Seokganju minerals. Only Seokganju mineral is used, it isnot suitable for black pigment into the transparent glaze. This study tried to develop a spinel crystal black pigment stabilizedby Seokganju with CoO, Cr2O3, NiO, and MnO2 at 1280oC. A Raman spectroscopy analysis was performed to verify thepresence of Mn The results showed that it existed as spinel, and two crystal phases CoFe2O4 and MnFe2O4 were mixed.CoFe2O4 spinel has a dark grayish black color and Mn2O4 spinel has a greenish black color, and these two appeared as black.The color of a specimen calcined by adding 6wt% of pigment mixed with 5wt% of MnO2 added to lime glaze was analyzedwith a UV spectrophotometer. When applying the color pigment, it appeared black stabilized with L*24.23, a* 0.12, b* −2.29at 1260oC oxidative calcination, With 1240oC reduction firing, it is appeared black stabilized with low brightness of L* 23.13,a* −1.12, b* 0.54.
