Correlation between the green-like coloration and the structural and electronic properties of celadon glazes (I)

Abstract

Celadon glazes have been investigated by means of ordinary X-ray fluorescence analysis, and X-ray diffraction and X-ray absorption spectra using synchrotron radiation. The tentative glazes are prepared by mixing raw celadon materials of Masuda feldspar, limestone, quartz, and extra-added Fe2O3 of about 1wt% at thermal treatment till about 1300 °C. It is found that the glaze-colors strongly depend on the Fe2O3 amount and the high-temperature treatment under oxidizing and deoxidizing in the used kiln. Especially, the characteristic color of blue-green, white-green-brown, and white-blue-green result from complex hybridized 3d5L and 3d6L bands. The 3d6L hybridization is induced by an electronic exchange interaction between an empty 3d6 orbital of Fe ions and an occupied 2p orbital of surrounding O ions in the (SiO2 - Al2O3 - CaO) basic complex ceramics of glass-state under the deoxidizing thermal treatment.

Propriedades estruturais e eletrônicas de óxidos de ferro em esmaltes celadon (II)

“…Thus, the smoothly small oscillating amplitude of the EXAFS spectra suggests that Fe ions are in glassy state of short-range order. We already confirmed that Seiji A, B, C, and D show the hallo-like X-ray diffraction pattern [6]. Thus, we are interested whether Fe ions in the celadon glaze are still in the micro-crystal state of Fe 2 O 3 or FeO structure or in non-crystal state to be perfectly complex free ions, because the EXAFS spectrum gives the structural information of the local circumstance around the X-ray absorbing ions in a material.…”

“…The incident X-ray photons (I o ) were detected with an ionic chamber set before the specimens, which were already shown in Fig. 1 of our first paper [6], while the X-ray fluorescence photons (I) emitted from the surface of the specimens were simultaneously detected with an X-ray fluorescence detector. The flat surface of specimen was always set with about 45.0° to the incident X-ray beam.…”

“…In the present investigations, the tentative celadon glazes were made by mixing raw celadon materials of Masuda feldspar, limestone, Hadong kaolin, quartz, and extra-added Fe 2 O 3 of about 1wt.%. The material properties of the used celadon glazes (Seiji A, B, C, and D) were already shown [6]. For comparison, Table I also lists a red-color overglaze of the Kakiemon-style porcelain, produced at Arita in 1670-80's [7 ].…”

“…It was also found that the celadon glaze includes microscopically the fine iron oxides of Fe 2 O 3 , but not FeO, under the deoxidizing thermal treatment of high-temperature, even if the celadon glaze is macroscopically in glass-state of short-range order. More recently, in order to reduce the intrinsic parameters related to the appearance of the glaze color, we tentatively made some celadon glazes under the oxidizing and deoxidizing thermal treatment and studied the structural and electronic properties of the glazes by means of the X-ray diffraction and the X-ray absorption spectra in our first paper [6]. The results suggested that the characteristic color of blue-green, white-green-brown, and white-blue-green result from the complex hybridized 3d 5 L and 3d 6 L bands of Fe ions.…”

Controlling the Color of Lead-Free Red Overglaze Enamels and a Process for Preparing High-Quality Red Paints

“…Although Takada’s report constitutes a pioneering study that tried to scientifically elucidate the essence of akae , the effect of particle dispersibility of hematite and its microstructure on the color of akae remains insufficiently understood. Recently, although some detailed investigations have been done into akae of the old Imari and Chinese porcelain from the historical viewpoint by using a state-of-the-art analytical method, the essential coloring mechanism of akae is still not clear. ,,− …”