Metallurgical analysis of a bronze powder chamber retrieved from an underwater excavation in Akko (Israel): an application of novel minimally destructive field multi-focal metallography

The Production of Marine Iron Objects in Europe Following the First Industrial Revolution: The Akko Tower Shipwreck Test Case

“…A minimally destructive FMM method was applied here for the first time on ancient ferrous objects (Figures 3, 10 and 15 and Supplementary Material Figures S3 and S7). This method was previously applied on a bronze powder chamber retrieved from an underwater excavation and demonstrated that the FMM method agrees well with conventional metallography [42]. The FMM method is an improvement in field metallurgical replication (FMR) metallography.…”

“…The minimally destructive testing (MDT) FMR metallography does not always produce the high-quality micrographs attained by conventional destructive metallography. The FMM is a powerful MDT method that involves the preparation of a curved or irregular surface in a similar way as the FMR method, and then observing the surface by a multi-focal light microscope instead of a standard optical light microscope, omitting the plastic film replication step used in the FMR method and directly observing the microstructure of the surface, as well as identifying microscopic defects related to the manufacturing process on-site after proper preparation, producing a high-quality image without having to cut samples and destroy unique archaeological objects [42]. The current observation of the objects by using the novel FMM method produced metallographic images comparable in quality to the images obtained by conventional metallography of destructively obtained samples set in Bakelite.…”

What You Clean Is What You Get: A Novel Chemical Cleaning Technique and the Interpretation of Corrosion Products Found in Late Roman Copper Alloy Coins Retrieved from the Sea

“…However, the above cannot be said for copper alloy objects deriving from marine environments. Very few studies focus on the cleaning process of ancient copper alloy objects retrieved from marine environments, and those that do are usually preoccupied with mechanical procedures [18,19]. For example, Iddan et al cleaned a bronze powder chamber from an underwater excavation in Akko with abrasive brushing [19].…”

“…Very few studies focus on the cleaning process of ancient copper alloy objects retrieved from marine environments, and those that do are usually preoccupied with mechanical procedures [18,19]. For example, Iddan et al cleaned a bronze powder chamber from an underwater excavation in Akko with abrasive brushing [19]. Consequently, copper objects retrieved from underwater settings do not enjoy the same broad knowledge base and even-headed treatment as those from terrestrial environments.…”

“…Coins recovered from the MMB shipwreck are covered with black, bluish, or green concretions, about 1 mm thick. These concretions obscure historically significant features and call for cleaning, which is usually conducted by sandblasting [5,18,19]. However, the results are often partial, especially when the concretion is hard, dense, and heterogeneous [5,18].…”