Chemistry versus phase constitution of yellow ancient tile glazes: A non-destructive insight through XAS

Maria-Ondina Figueiredo, João Pedro Botelho Veiga, T. P. Silva, José Mirão, S. Pascarelli

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16 Citations (Scopus)

Abstract

Using synchrotron radiation-based analytical (SRXRF) and spectroscopic (XAS) non-destructive techniques, a study was carried out on lead-rich, tin-opacified yellow glazes (silica-lime-alkali type glasses) decorating ancient tiles (17-19th century). These glasses have a rather complex chemistry, being currently assumed that the yellow pigment used for centuries - a pyrochlore-type double oxide of lead and antimony - prevails within the glaze, despite Sb(3+) being recognized as a network-forming cation in glasses. Minerals and synthetics with known crystal structure were used as model compounds to interpret X-ray absorption spectroscopy data at Sb K-edge and Pb L-3-edge collected from ancient glazes. Theoretical modelling of Sb 1s XANES spectra was applied to demonstrate that antimony alone may be responsible for the yellow colour through a finely dispersed pyrochlore-type Sb-oxide, while lead remains hosted in the glassy matrix. (c) 2005 Elsevier B.V. All rights reserved.
Original languageUnknown
Pages (from-to)134-137
JournalNuclear Instruments & Methods In Physics Research Section B-Beam Interactio
Volume238
Issue number1-4
Publication statusPublished - Aug 2005

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