高麗遊児書像鏡の金属組織と不純物

抄録

  The microstructure and impurities in a Korai (10~14c) Bronze Mirror illustrated with four boys with musical instruments has been investigated. Transmission electron microscope, X-ray diffractometer, scanning electron microscope, and electron dispersive X-ray analyses are used to determine the structure of the specimen. The composition of the specimen is Cu-9.7 mass%Pb-10 mass%Sn-0.6 mass%S, and Ag and Si are detected as trace elements. The microstructure of the Korai bronze mirror consists of αCu, αCu₄₁Sn₁₁, Pb, and a phase containing S. It is clarified that the phase containing S is Cu₂S (JSPDS 33-0490) by electron diffraction pattern analysis. It is thought that Cu₂S is a residue of the intermediate product, Cu₂S, in the refining of the copper ore, chalcopyrite (CuFeS₂). Therefore, the copper ore has not been completely refined. Fine Pb particles are observed in the Cu₂S grains, and fine PbS crystals also exist between Pb and Cu₂S.