Laser-induced breakdown spectroscopy study of silversmith pieces: the case of a Spanish canopy of the nineteenth century

Abstract

Canopies of needlework velvet or silversmith pieces placed on twelve or more battens are widely employed in Spanish catholic ceremonies to cover the image of the virgin. In this paper, we focus our interest on those pieces made of silver. These silver crafts suffered a revolution in the nineteenth century with the development of an electrolyte system that can be applied over carved metal pieces, in order to obtain a silver layer by electrodeposition similar in appearance to the original sterling silver and cheaper. The aim of this research was the application of laser-induced breakdown spectroscopy (LIBS) to the study of a canopy of the nineteenth century in order to assess the techniques used for its manufacturing and the identification of replacement and restoration of original pieces. The LIBS depth profiles show the presence of a micron silver layer over an alloy of copper and zinc in most of the surfaces. Corrosion products, alloy missing, and the restoration with copper layers were detected. These results are consistent with those obtained by scanning electron microscopy with energy-dispersive of X-ray with the advantage that LIBS is a methodology that allows analysing metal pieces without sampling or preparation. In summary, LIBS is a technique that allows the study of silversmith pieces with electrochemical preparation according to the Ruolz technique, and it is also possible to detect subsequent restoration or corrosion zones.

Application of Laser-Induced Breakdown Spectroscopy for Quantitative Analysis of the Chemical Composition of Historical Lead Silicate Glasses

“…Currently, there are many articles describing the use of LIBS in cultural heritage [17][18][19][20]. This method has been successfully applied to the in-depth analysis of chemical compositions of samples, as well as for multilayer objects [21][22][23]. This is because part of the material evaporates when a laser pulse is applied to the surface of the sample.…”