重庆大足大佛湾彩绘绿色和蓝绿色颜料的分析研究

Study of copper and arsenic-containing green and blue-green pigments of rock carvings at Big Buddha Bay in Dazu

为了确定重庆大足大佛湾彩绘含铜、砷元素的绿色及蓝绿色颜料显色成分,应用便携式X射线荧光光谱仪(XRF)、便携式显微镜等无损调查方法,结合X射线衍射分析仪(XRD)、扫描电镜-能谱仪(SEM-EDX)、X射线光电子能谱分析仪(XPS)、显微拉曼光谱仪(RM)等分析方法,对取自大佛湾塑像的绿色及蓝绿色颜料进行调查和分析。结果表明绿色颜料显色成分为为巴黎绿[Cu(CH3COO)2·3Cu(AsO2)2],蓝绿色颜料显色成分为氯砷钠铜石[NaCaCu5(AsO4)4Cl·5H2O]。根据研究结论推断,氯砷钠铜石可能为巴黎绿的变色产物。该结果为探讨近代人工合成颜料变色机理提供了新的线索和方法。

The chromogenic copper and arsenic-containing green and blue-green pigments of rock carvings at Big Buddha Bay in Dazu,Chongqing,were investigated and analyzed using portable X-ray fluorescence spectrometry(XRF),portable microscopy and other non-destructive analysis methods in combination with X-ray diffraction(XRD),scanning electron microscopy-energy dispersive X-ray spectrometry(SEM-EDX),X-ray photoelectron spectrometry(XPS)and micro Raman spectrometry(RM).The results show that the chromogenic component of the green pigment is emerald green[Cu(CH3COO)2·3Cu(AsO2)2],and that of blue-green pigment is lavendulan[NaCaCu5(AsO4)4Cl·5H2O].Also,it is inferred that lavendulan is a discoloration product of emerald green,based on this research.This work provides new clues to and methods for research on the chromogenic changes in modern synthetic pigments.