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A Synchrotron-based study of the Mary Rose iron cannonballs

DOI: 10.1002/anie.201713120 DOI Help

Authors: Hayley Simon (University College London (UCL); Diamond Light Source) , Giannantonio Cibin (Diamond Light Source) , Phil Robbins (Diamond Light Source) , Sarah Day (Diamond Light Source) , Chiu Tang (Diamond Light Source) , Ian Freestone (University College London (UCL)) , Eleanor Schofield (Mary Rose Trust)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Angewandte Chemie International Edition , VOL 30

State: Published (Approved)
Published: March 2018
Diamond Proposal Number(s): 16328

Open Access Open Access

Abstract: Post-excavation iron corrosion may be accelerated by the presence of Cl−, leading to conservation methods designed to remove Cl. This study exploits a unique opportunity to assess 35 years of conservation applied to cast-iron cannon shot excavated from the Mary Rose. A combination of synchrotron X-ray powder diffraction (SXPD), absorption spectroscopy (XAS), and fluorescence (XRF) mapping have been used to characterise the impact of conservation on the crystalline corrosion products, chlorine distribution, and speciation. The chlorinated phase akaganeite, β-FeO(OH,Cl), was found on shot washed in corrosion inhibitor Hostacor IT with or without an additional reduction stage. No chlorinated phases were observed on the surface of shot stored in sodium sesquicarbonate (Na2CO3/NaHCO3); however, hibbingite, β-Fe2(OH)3Cl, was present in metal pores. It is proposed that surface β-FeO(OH,Cl) formed in the early stages of active conservation owing to oxidation of β-Fe2(OH)3Cl at near-neutral pH.

Journal Keywords: archaeology; chlorine; corrosion; iron; X-ray absorption spectroscopy

Subject Areas: Archaeological and Cultural Heritage, Chemistry


Instruments: B18-Core EXAFS , I11-High Resolution Powder Diffraction

Documents:
Simon_et_al-2018-Angewandte_Chemie_International_Edition.pdf