Mössbauer Spectroscopic and Chromaticity Analysis on the Colourative Mechanism of Ancient Goryeo Celadon from GangJin and Buan

Abstract

In ancient Goryeo celadon excavated from the kiln sites in the GangJin and Buan areas, the effect of the chemical composition and ionic state of Fe on the colour was evaluated by Mössbauer spectroscopy and chromaticity analysis. According to chromaticity analysis, the L* value (brightness) of the glaze was shown to be affected more by TiO2 and MnO than by Fe2O3, and the body was affected more by Fe2O3 than by TiO2. The a* value was found to be affected by Fe2O3 and TiO2 in the glaze, whereas there was hardly any change in the body according to the composition. As for the b* value, changes due to the composition were shown to be smaller than those for the L* and a* values. According to the Mössbauer spectroscopy results, as the quantities of TiO2 and Fe2O3 are increased, Fe2+/Fe3+ decreases; while the changes in Fe2+/Fe3+ with MnO and P2O5 are negligible. As the quantity of Fe2+/Fe3+ increases, the a* and b* values decrease, which results in the change of colour from red–yellow to blue–green. The characteristic green colour can be attributed to increased L* (brightness) and decreased a* and b* values (blue–green shift) due to the reduced Fe ion, which is mainly determined by the TiO2 and Fe2O3 contents.

Historical copper and iron coloured glazes and glasses

“…This thin layer under the glaze acts as a dark background over which the scattering and absorption of light in the glazes is not affected by the stoneware. The brown colour is attributed to the incorporation of Ti 4+ from the stoneware with the consequent concomitant oxidation of Fe 2+ to Fe 3+ and reduction of Ti 4+ to Ti 3+ (Figure 4.4) (Kim 2001, Jeon 2014. Indeed, in good agreement with this, a recent investigation using Mössbauer spectroscopy has shown that the brown glaze is more oxidised than the blue glaze in Jun ware .…”

Identification of Historic Artists' Pigments Using Spectral Reflectance and X-Ray Diffraction Properties I. Iron Oxide and Oxy-Hydroxide-Rich Pigments

“…Therefore, RS can serve as a viable non-destructive alternative to Mössbauer spectroscopy (which is very slow and expensive) for determining the oxidation state and mineralogy of Fe-bearing phases. 48 Reflectance spectra of the pigments included in this study demonstrate that the spectral dominance of Fe oxyhydroxides generally decreases toward longer wavelengths. Thus, while even small amounts of Fe oxy-hydroxides can dominate the spectral properties below ~1200 nm, at longer wavelengths other phases, such as clays and gypsum can be detected.…”

Properties of Kaolinite as a Raw Material for Porcelain

“…In contrast, as the sintering temperature is increased in the reducing atmosphere, the whiteness is increased, because Fe 2 O 3 is reduced to FeO. [5][6][7] The whiteness is the lowest when the sintering is completed. When the temperature is continuously increased beyond the sintering point, the whiteness is increased by the appearance of the glass phase.…”