The aim of this work is the characterization, with different diagnostic tests, of three fragments of bronze artefacts recovered from the Villa of the Quintilii (located in the south of Rome). In particular, the sample alloys were investigated by different chemical and morphological analysis. Firstly, an analysis of the alloy, implemented through the electronic spectroscopy, was taken to discriminate the bronze morphology and its elemental composition. Subsequently, a surface analysis was realized by molecular spectroscopy to identify the alteration patinas on surfaces (such as bronze disease). Two diagnostic techniques are used for the alloy analysis: scanning electron microscopy (SEM) connected to the EDX spectroscopy (to study the morphology and alloy composition) and Auger electron spectroscopy (AES) (to identify the oxidation state of each element). Moreover, for the study of surface patinas, IR and Raman spectroscopies were implemented. All studies were performed on the “as received” samples, covered by a thin layer of excavated soil and on samples processed in an aqueous solution of sulphuric acid (10%), to remove patinas and alterations. 1. Introduction The diagnostics of cultural heritage are based on physical methods and chemical-physical properties to obtain information on artefact chemical composition and their physical characteristics. The aim of diagnostic tests is the study of artefact construction technique and execution, providing information about the original materials, their preservation state and on alteration products present on the artefact. Usually, the study of material surface is performed by different electron and/or photonic spectroscopies. The analysed object is “bombarded” with particles or electromagnetic radiation to obtain chemical and morphological information on the first monolayer or on the first surface layers (depth of few microns). The analysis of artefacts surface is important because it is the interface with the external environment and then it represents the border layer for the object (e.g., oxide film on a metallic material). Moreover, the surface may affect the aesthetic appearance and can reveal the products of degradation (e.g., bronze disease). So, the surface characterization becomes crucial where the interaction phenomena with the external environment modify the artefacts. Moreover, the characterization of corroded layers is important to explain the causes of the degradation process. Bronze patinas, in fact, are generally associated with the thin layer of products observed on ancient metals and alloys.
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