Korean Journal of Materials Research ISSN:1225-0562(Print) 2287-7258(Online) 한국재료학회지

In this study, an α-Fe₂O₃ (hematite) coated porcelain plate was sintered in a temperature range from 1100 oC 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-Fe₂O₃ (hematite) was densely fused to the surface at several tens of μm, the α-Fe₂O₃ (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-Fe₂O₃ (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.