元代都城琉璃瓦釉层的EDXRF和SEM-EDS分析

X-Ray Fluorescence Spectroscopy Combined With SEM-EDS Analysis to Glaze Composition of Glazed Tiles in Yuan Dynasty

元代的琉璃瓦制作技术承自宋辽,对明清产生重要影响,是中国琉璃瓦制作技术发展的过渡时期。元上都与元中都所使用的琉璃瓦,代表了元代早期和中期琉璃瓦制作技术的最高水平。为探索元代不同时期琉璃瓦的制作技术和工艺特点,结合考古资料与相关文献,以X射线荧光光谱法(EDXRF)为基础,结合扫描电镜与能谱仪(SEM-EDS),对元上都遗址、元中都遗址出土琉璃瓦样品釉层组成进行了测定。分析结果显示,元上都与元中都釉层包括釉与化妆土,化妆土厚度在122~260μm之间。元上都孔雀蓝釉琉璃瓦釉料属于PbO-K_(2)O-SiO_(2)体系,和元大都孔雀蓝釉组成相似,原料组成为石英、硝、铅末、铜末;蓝釉琉璃瓦化妆土结构致密,CaO与SiO_(2)含量大于20%,原料可能是钙长石与黏土,应是釉料的一部分。元上都绿釉与元中都绿釉黄釉琉璃瓦釉同为PbO-SiO_(2)体系,基本原料组成都为石英,铅末,着色剂分别为铜与铁。元上都绿釉配方与北宋时期的接近,釉料配方也符合《营造法式》记载,但逐渐减少铅的比例为获得更浅的釉色,在元中期逐渐稳定;元中都黄釉琉璃瓦釉料铅硅比与元大都相近,配方在元中期探索中逐渐固定,沿用至明代早期,是提升明中期釉料的基础;两处遗址绿釉琉璃瓦与元中都黄釉琉璃瓦化妆土与胎釉结合紧密,Ca含量很高,厚度较薄,很可能是石灰浆[Ca(OH)_(2)],工匠在施加化妆土时既节约成本又能提高产品质量。三种釉色分别属于PbO-K_(2)O-SiO_(2)与PbO-SiO_(2)两种体系,组成原料差异明显,都用于建筑装饰,极大丰富了琉璃釉色,化妆土的应用在琉璃技术中也是一项创新。能量色散X射线荧光光谱具有分析快速、状态稳定的特点,已在琉璃瓦测试研究中得到普及,而元上都元中都琉璃瓦釉层的研究结果,补充了元代琉璃瓦的研究资料,并对探索中国琉璃瓦工艺发展历程提供一定科学依据。

The glazed tile production technology of the Yuan Dynasty was inherited from the Song and Liao dynasties,which had an important impact on Ming and Qing Dynasties.It was a transitional period for the development of glazed tile production technology in China.The glazed tiles used in Shangdu and Zhongdu of the Yuan Dynasty represent the highest glazed tile production technology in the early and middle Yuan Dynasty.In order to explore the manufacturing technology and process characteristics of glazed tiles in different periods of Yuan Dynasty,this paper analyzes the composition of glaze layer of glazed tiles unearthed from the Yuanshangdu and the Yuanzhongdu by EDXRF and SEM-EDS,combined with archaeological data and related literature.The results show that the glaze layer of the Yuanshangdu and the Yuanzhongdu includes glaze and clay,and the thickness of clay is between 122 and 260μm.The glaze of Shangdu Malachite blue glazed tile belongs to the PbO-K_(2)O-SiO_(2) system,which is similar to that of Yuandu Malachite a blue glaze.The raw materials are composed of quartz,nitrate,lead powder and copper powder.The structure of blue glazed tile is compact,and the content of Cao and SiO_(2) is more than 20%.The raw materials may be anorthite and clay,which should be a part of the glaze.Shangdu green glaze and Zhongdu green glaze yellow glaze tile glaze are both Pbo-SiO_(2) systems.The basic raw materials are quartz,lead powder,and colorants are copper and iron respectively.The formula of green glaze in the Yuanshangdu is close to that of the Northern Song Dynasty,and the formula of glaze is also in line with the records of“Yingzao Fashi”,but the proportion of lead is gradually reduced to obtain lighter glaze color which is stable in the middle of Yuan Dynasty.The Pb/Si of yellow glazed tile in the Yuanzhongdu is similar to that of the Yuandadu,and the formula is gradually fixed in the exploration during middle period of Yuan Dynasty which is the basis of improving glaze during middle period of Ming Dynasty.All the glazed tiles’glaze is closely combined with body and slip.The clay has a high content of Ca and a thin thickness.It is likely to be Ca(OH)2.The craftsman can not only save the cost but also improve the product quality when applying the clay.The three kinds of glaze colors belong to PbO-K_(2)O-SiO_(2) and PbO-SiO_(2) systems respectively,with obvious differences in composition materials.They are all used in architectural decoration,which greatly enriches the glaze color of the glass.The application of make-up clay in glass technology is also an innovation.Energy-dispersive X-ray fluorescence spectroscopy has the characteristics of fast analysis and stable state,which has been widely used in the research of glazed tile.The research results of glazed tile in Shangdu and Zhongdu of Yuan Dynasty supplement the research data of glazed tile in the Yuan Dynasty,and provide some scientific basis for exploring the development history of glazed tile technology in China.