|Institution:||Delft University of Technology|
|Keywords:||Bronze; Geistingen; Axe; Late Bronze Age; Production; Archaeometallurgy|
|Full text PDF:||http://resolver.tudelft.nl/uuid:68dd2bd5-97ef-42ab-be75-f13da4bb5f11|
Samples from two bronze Geistingen axes, one from Nijmegen and one from Tongeren, are examined and analysed in order to answer the question ‘How are they produced?’. It is concluded that both axes do not have the same composition: the Nijmegen axe is identified as a binary copper-tin bronze, while the Tongeren axe is regarded as a ternary copper-antimony-nickel alloy. Both axes possess a porous dendritic microstructure with an interdendritic phase, which is typical for a cast material. In between these phases, Cu2S- and lead-antimony particles are present. The axe from Nijmegen also contains silver particles in addition to the previously mentioned ones. It is assumed that these particles all originate from the raw material, namely the ores used, and that they are formed in the melt. The melt of both axes has been at least at a temperature of 1150 °C, based on the presence of Cu2S-particles. Probably, both objects are water-cooled after pouring the liquid in the mould, according to the secondary dendrite arm spacing. This spacing indicates that the two axes are formed with different cooling rates. No subsequent working of the axes has taken place on the sampling locations. In conclusion, the two Geistingen axes are produced by co-smelting the same types of ore in different ratios. The bronze is consequently cast into a bi-valve mould. This is then water-cooled to let the object solidify. No subsequent hot- or cold-working has taken place.