Characterization of hematite red pigment for porcelain surface coating

초록

In this study, an α-Fe<inf>2</inf>O<inf>3</inf> (hematite) coated porcelain plate was sintered in a temperature range from 1100 °C to 1250 °C using ferrous sulfate. The specimens were investigated by X-ray diffractometer (XRD), scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), and UV-visible spectrophotometer. It was confirmed that α-Fe<inf>2</inf>O<inf>3</inf> (hematite) was densely fused to the surface at several tens of μm, the α-Fe<inf>2</inf>O<inf>3</inf> (hematite) was in the form of thin platelet and polyhedra, and no other compounds appeared in the sintering process. In the specimen coated with α-Fe<inf>2</inf>O<inf>3</inf> (hematite), the reflectance spectra show a red absorption band of 560-650 nm. The L* value decreased from 53.18 to 46.94 with the firing temperature. The values of a* and b* were at 19.03 and 15.25 at 1100 °C and gradually decreased with increasing temperature; these values decreased rapidly at 1250 °C to 11.54 and 7.98, respectively. It is considered that the new phases are formed by the phase transition of the porcelain plate (clay), and thus the a* and b* values are greatly influenced. © Materials Research Society of Korea.

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