红绿彩瓷之釉上彩的XAFS研究

X AFS analysis of ancient Chinese porcelain of Honglvcai

红绿彩瓷是一种低温釉上彩瓷,从结构层次探讨其釉上红彩、绿彩、黄彩的呈色机理一直是古陶瓷研究的空白。采用X射线吸收精细结构(X-rayabsorption fine structure,XAFS)方法,测试分析红绿彩瓷中的红彩、绿彩和黄彩。结果表明,红彩中致色元素Fe主要为+3价,其局域结构与Fe2O3相近,最近邻配位为扭曲的八面体结构。透射电子显微分析证实其物相为氧化铁晶体。黄彩中致色元素Fe主要存在+2价和+3价,绿彩中致色元素Cu主要为+2价,两者均处于无序度较高的局域环境中,最近邻配位为O原子。

Structure analysis of Honglvcai, an overglaze ploychrome porcelain produced in China from the Song Dynasty to Ming Dynasty, has been a blank in studies on ancient Chinese ceramics. This work was focused on the oxidation state and local environment of colorants in red, yellow and green decorations on Honglvcai by X-ray absorption fine structure （XAFS）. The analysis of Fe K-edge XANES and EXAFS spectra of the red-colored samples indicated that Fe^3＋ was mainly located at a distorted octahedral site in a hematite phase, while that if the yellow-colored samples showed that iron was present as both trivalent and divalent cations coordinated with oxygen atoms in an amorphous phase. And Cu K-edge XAFS analysis of the green-colored samples revealed that Cu^2＋ was the main constituent coordinated with oxygen atoms in an amorphous phase.