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M. Griesser, W. Kockelmann, K. Hradil, R. Traum:
"New insights into the manufacturing technique and corrosion of high leaded antique bronze coins";
Microchemical Journal, 126 (2016), S. 181 - 193.

Selected ancient Greek bronze coins held in the Coin Collection of the KunsthistorischesMuseumVienna (KHM)
were studied concerning their preservation and conservation. The coins had been minted during the Roman Imperial
time (50 to 280 AD) using alloyswith high lead and/or tin contents. Today a number of these highly leaded
bronze coins, altogether different singular pieces, show progressive whitish corrosion in spots or well-defined
areas on their surfaces. Different analytical techniques were used for the documentation and study of the different
states of corrosion, the corrosion phases developing in the whitish parts as well as the cause of the specific
corrosion phenomena.
Further studies focused on the analysis of the corrosion phases - combining results fromμ-XRD and neutron diffraction
investigations - as well as on the manufacturing techniques of the antique Greek coins. The μ-XRD analysis
applied a beam spot of 300 μm allowing for a localised determination of corrosion phases on the surfaces of
the objects. The main corrosion products consist ofmetal (Cu, Pb, Cu/Sn) oxide phases. As minor components also
metal sulphide and chloride phases could be assigned. To enable the distinction between different manufacturing
techniques 35 coins and eight self-made `replicas´ were analysed in a non-destructive way by bulk neutron texture
analysis which reveals changes in the microcrystalline structure of the alloys related to the mechanical
minting processes.

Bronze coins, corrosion, manufacturing techniques, micro-X-ray diffraction, neutron diffraction, texture analysis

http://dx.doi.org/10.1016/j.microc.2015.12.002