SEM-EDS ANALYSIS OF CONSOLIDANTS APPLIED OP LIMESTONE AND PROCONNESIAN MARBLE

摘要

Synthetic polymers and inorganic products were widely used, from the '60s of the past century, for the protection and the consolidation of stone surfaces of Venetian monuments. In general, the application slowed down the decay, although over time, different types of deterioration may be observed. They include chemical alterations of the treatment materials, involving the formation of oxidized species (chromatic variations of the surfaces) and physical modifications such as the formation of a "craquele" and pulverisation of aged products leading to the de-cohesion of the stone substrate. A chemical investigation of the alteration of consolidants and protectives applied on Venetian stone artefacts is particularly interesting since it allows verifying the behaviour after several decades of exposure in a very aggressive environment. μ-FTIR analysis (Fourier-transform infrared spectroscopy) is used to identify employed products (whose exact nature is not always known) and their chemical-physical characteristics. In addition, SEM analysis is proposed as a useful methodology to investigate the morphology of applied products, their distribution inside the pores and to identify the possible presence of other products previously applied. Furthermore by SEM-EDS analysis, we intend to verify the elementary composition of the treatments based on inorganic products and the possible presence of secondary decay products. In the poster we present the preliminary results obtained from the investigation of samples treated in the '70s and '80s of the past century of white Vicenza limestone and Proconnesian marble. The applied methodology proved adequate to the aim of the research and will be extended to other stone material of Venetian buildings.