清代红绿彩瓷器无损分析研究

红绿彩瓷器是我国陶瓷史上一种重要的釉上彩瓷器，分析其彩料的化学组成和物相结构对其烧制工艺的研究有很重要的意义。但由于瓷器表面的不平整和彩料分布的不均匀性，导致其不满足传统的1 mm×10 mm线光源的X射线衍射仪对样品的测试要求。而毛细管聚焦的X射线衍射仪采用点光源的方式照射样品，毛细管X光透镜对Cu-K_α的能量有高达3个数量级的放大倍数，同时具有低的发散度，能实现样品直径100 μm的微区和直径3 mm的常规X射线衍射分析，非常适合古陶瓷类样品矿物结构的无损分析的研究。因此，应用毛细管聚焦的微束X射线荧光谱仪和毛细管聚焦的X射线衍射谱仪对江西景德镇出土的清代红绿彩瓷的白釉和釉上彩料的化学成分和物相结构进行分析，并对红绿彩瓷彩料中2 mm×2 mm感兴趣区域内多元素分布和矿物相的分布进行了二维扫描分析。结果表明，Cu为绿彩的主要着色元素，在绿彩中的含量为0.02%，部分以Pb₈Cu(Si₂O₇)₃（PDF 31-0464）晶相形式存在；Fe为红彩的主要着色元素，Fe含量为1.63%，部分Fe元素以Fe₂O₃（PDF 47-1409）的晶相形式存在；其中Pb在绿彩和红彩中的含量分别为41.49％和6.29%，其主要作用是使彩料的熔点降低，部分Pb在700～800 ℃的烧制过程中与Cu元素和Si元素相结合以Pb₈Cu(Si₂O₇)₃（PDF 31-0464）晶相形式存在。从扫描区域内的元素分布图和晶相分布图可以看出，彩料原料中着色元素Cu和Fe的矿物晶相与Cu和Fe的元素分布不一致，表明原料中原有的Cu和Fe的矿物晶相在烧制过程中基本上都消失了，仅剩余或生成部分Fe₂O₃晶相；白釉中存在莫来石晶相，说明白釉是在高温下烧制而成；其中Pb₈Cu(Si₂O₇)₃晶相的形成温度在750 ℃左右，因此可以进一步说明清代红绿彩的绿彩料是在低温下烧制而成。以上结果说明，毛细管聚焦的微束X射线荧光和毛细管聚焦的微束X射线衍射谱仪在文物的科技研究中有着重要的应用前景。

Non-Destructive Analysis of Red and Green Porcelain in Qing Dynasty

The red and green colored porcelain is an important overglaze colored porcelain in the history of Chinese ceramics. It is significant to analyze the chemical composition and phase structure of the colored pigments to study the process of fired technologies. However, the traditional X-ray diffractometer with a 1 mm×10 mm line source is not easy to measure the porcelain sample of uneven surface and unevenly distributed color material. The capillary-focused X-ray diffractometer has a point X-ray beam to irradiate the sample. The capillary X-ray lens has a magnification of up to 3 orders of magnitude to the energy of Cu-Kα and has a low divergence of the X-ray beam. Therefore, it can measure the sample with a diameter of 100 micrometers and the conventional X-ray diffraction analysis of a sample with diameter of 3 mm, which is very suitable for the non-destructive analysis of the mineral structure of ancient ceramic samples. This article reports the results of the chemical composition and phase structure of the white glaze and red and green-colored pigments in the Qing Dynasty unearthed in Jingdezhen, Jiangxi province by the capillary focused microbeam X-ray fluorescence spectrometer, and the capillary focused X-ray diffraction spectrometer developed by our laboratory. It carried out the two-dimensional scanning analysis of the distribution of multi-element and mineral phases in the interest region (2 mm×2 mm) of the red and green colored porcelain. The results show that at first, Cu is the main coloring element of green colored pigments and the concentration of Cu in green colored pigments is 0.02%. Moreover, parts of Cu exist in the form of the Pb₈Cu(Si₂O₇)₃ crystal phase. Secondly, Fe is the main coloring element of red-colored pigments, and the contractions of Fe in red-colored pigments is 1.63%, and parts of Fe exist in the form of the Fe₂O₃ crystal phase; Thirdly, the concentrations of Pb in green and red-colored pigments is 41.49% and 6.29%, respectively. The main function of Pb is to lower the melting point of the colored pigments, and parts of the Pb combined with Cu and Si during the firing process at 700～800 ℃ to exist in the form of Pb₈Cu(Si₂O₇)₃ crystal phase. From the element 2D mapping and crystal phase mapping, it is obvious that the crystal phase of the coloring elements Cu and Fe in the colored pigments is inconsistent with the element distribution of Cu and Fe. It indicates that the Cu and Fe mineral crystal phases in the raw materials may disappear during the firing process, and the Fe₂O₃ crystal phases have been left or generated during the process of firing or cooling. The mullite crystal phase in the white glaze indicates that the white glaze fired at a high temperature. However, the formation temperature of the Pb₈Cu(Si₂O₇)₃ crystal phase is only about 750 ℃, which can further explain that the red and green colored pigments were fired at low temperatures. In general, the capillary-focused microbeam X-ray fluorescence spectrometer and the capillary-focused microbeam X-ray diffraction specrometer could have important application prospects in cultural relics’ scientific and technological research.