铜镜表面“黑漆古”中“痕像”的研究

STUDY OF MINERALIZED GHOST PSEUDOMORPHIC MICROSTRUCTURE IN THE SURFACE OF A "HEI-QI-GU" MIRROR

采用矿相薄片制备方法暴露出“黑漆古”矿化层。矿相显微镜下偏光现察，此矿化层透光、且具有原金属的α与δ痕像及较多圆形颗粒，说明此矿化层是铜镜自身的组成部分而不是附加在镜面上的沉积物或镀锡层腐蚀产物。此矿化层的ＳＥＭ能谱分析显示，ａ与ａ痕像以及圆形颗粒在成分上是十分相近的，是高Ｓｎ、低Ｃｕ并含有一定量的Ｐｂ、Ｓｉ、Ｆｅ。ＸＰＳ及ＸＲＤ分析结果显示铜镜“黑漆古”表面以ＳｎＯ２。细晶为主要组成。以上研究结果对探讨“黑漆古”形成机理提供直接证据。进一步表明矿化层的形成是在铜镜埋葬环境下腐蚀作用的结果，发生了氧化－络合－凝胶析出及脱水等一系列化学变化。

A mineralized layer in the top surface of a 'Hei-Qi-Gu' mirror was exposed by introducing the method for preparing mineralographic thin slides. It is transparent and has ghost pseudomorphic a and δ phases and many globules under the polarized light of a mineralographic microscope. This indicates that the mineralized layer is a constituent of the mirror itself and that it is neither an extra deposit on the mirror surface nor a corroded film of tin on the surface rubbed with Xuanxi (Tin amalgam).SEM analysis shows that both the ghost pseudomorphic α andδ and the globules aresimilar in composition: Sn content is quite high,Cu content is very low, and some Pb, Si andFe are.also contained in them. XPS and XRD reveal that SnO2 is the main constituent andSnO2 crystals are very fine.The results provide a direct evidence for studying the mechanism of formation of 'Hei-Qi-Gu',and further indicates that the mineralized layer was formed naturally in corrosionprocesses during burial.A series of chemical reactions including oxidation, complexing, hydration, hydrolysis,gelatination and geldecomposition took place.