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XPS METHOD FOR ANALYSIS OF ANCIENT «LACQUERISH PATINA» (57)

i •»•!•••• •! •••••• ••!•! ••••• ••••• ••!•! •!•!• !•!•• II|| IIII Zhou, Z. MX0000193 Institute of History of Sun, S. and Materials Han, R. University of and , Ko,T.

Among ancient bronze mirrors, the «lacquerish patina» (Qi Gu) mirrors attracts much attention, owing to their jade-like gloss and anti- property. The mechanism of the formation of «lacquerish patina» surface on the bronze mirrors attracting many archaeometallurgical scholars but until recently without convincing result. A new modern analysis method, X- Photoelectron was used to analyze the «lacquerish patina» surface on ancient bronze mirrors. From examinations by XPS, it can be suggested that the outer surface layer of «lacquerish patina» mirrors is mainly composed of Sn, Cu and O, and few trace elements of Pb, Al, Si, Ca. There are not distinct difference among the element compositions of outer surface layer of different colour «lacquerish patina» mirrors; The composed elements of outer surface layer of metallic shiny mirrors are same as «lacquerish patina» mirrors, and the content of are higher than «lacquerish patina» mirrors. It is suggested that the «lacquerish patina» layers are the result of natural corrosion. KEYWORDS: Bronze , Lacquerish patina, XPS.

A STUDY OF AND CADMIUM FOR THE DATING AND AUTHENTICATING OF REMAINS IN ANCIENT CHINA (58)

Zhou, W. China Numismatic Museum, China

With the development of application of modern experimental techniques in the field of , some efficient scientific methods for the dating and authenticating of earthenware, porcelain, flint, and organic relics are found. But, for the dating and authenticating of metal remains, current experimental techniques seem useless. After analyzing thousands of ancient Chinese copper-based metal remains (coins and artifacts) by wet method and AAS, we found several rules as follow. In articles dated from the Shang Dynasty to the Han Dynasty (17th century BC - 220 AD), zinc content is very low, usually lower than 0.5% and never reaching 1%. Chinese coins issued before the middle Ming Dynasty (the middle period of 16th century) are all made of bronze and noticeable zinc is only found in the coins from the mid-16th century onwards. In coins issued before 1621 cadmium content is very low, usually below 0.0010% (10 ppm), and after this date the cadmium concentration is often much higher although it never exceeds trace amounts. It is a very division between cementation brass and speltering brass. Putting those into the history of Chinese metallurgy, we can find that they are very useful for the dating, authenticating and provenance of metal relics in ancient China. KEYWORDS: , Ming dynasty, China.