Raman and X-ray fluorescence glaze characterisation of Maria Keil's decorative tile panels

A set of decorative contemporary tile panels, created by the Portuguese artist Maria Keil (1914-2012) for the Lisbon metro stations, was studied under a noninvasive analytical methodology. This methodology combines X-ray fluorescence spectrometry (mu-XRF) and Raman spectroscopy in microscopic (mu-Raman) mode for an elemental and structural composition characterisation of the glaze (glass matrix and network modifiers such as fluxes, opacifiers and colouring agents). mu-XRF quantitative evaluation of the glassy matrix shows that all glazes have a lead silicate glass base. Results obtained by the combined use of mu-XRF and mu-Raman show that a zirconium-based opacifier was used. Naples yellow (Pb2Sb2O7), lead-tin yellow type II (Pb(Sn,Si)O-3), Pb-Sn-Sb triple oxide, cobalt blue (CoAl2O4), chromium oxide (Cr2O3) and malayite sphene (CaO center dot SnO2 center dot SiO2) have been identified by mu-Raman as some of the colouring agents, either used by themselves or in mixtures for obtaining the desirable colours intended by the artist.

Automated summary

A study was conducted on a set of decorative contemporary tile panels created by Portuguese artist Maria Keil for Lisbon metro stations, revealing the use of lead silicate glass base, zirconium-based opacifier, and various coloring agents such as Naples yellow, lead-tin yellow type II, Pb-Sn-Sb triple oxide, cobalt blue, chromium oxide, and malayite sphene.