Application of XRF, XRD, thermal analysis, and voltammetric techniques to the study of ancient ceramics

Abstract

An in-depth chemical-analytical study has been performed on biscuit and mortar from 17th-18th century tiles from a mediaeval hermitage in the province of Valencia (Spain). Representative samples were chosen from the tile fragments available, using appearance, essentially color and consistency, as the criterion. The chemical composition was analyzed by X-ray fluorescence of the samples in the form of glass disks after a previous qualitative study to choose the standard materials for calibration and the experimental conditions used in the analysis. X-ray diffraction of the samples provided information about the mineralogical composition which was consistent with the firing of the original materials; it also gave information about the range of temperatures used in the firing. From thermal gravimetric analysis of the limestone, and from historical considerations, it was possible to deduce the raw materials used and their approximate composition in the tiles. In the same way it was possible to determine the nature of the mortars used to fix the tiles. Cyclic voltammetric study of the iron(II) and iron(III) system in the biscuit showed the simultaneous presence of both oxidation states, corroborating the results.

Discrimination and Provenances of Phoenician Red Slip Ware Using both the Solid State Electrochemistry and Petrographic Analyses

“…As judged upon comparison with the voltammogram of hematite in Figure c and literature data on HCl electrolytes , the signals C1–C4 correspond to the reduction of hematite and other Fe(III) minerals following different pathways. It is pertinent to note that the reduction of Fe(III) species is sensitive to the chemical composition but also to the crystallinity and degree of hydration of the electroactive components so that the prominent signal C1 can be attributed to the reduction preceded by proton‐assisted surface dissolution (roughly, CE mechanism) forming surface, solution‐like Fe(III) species reduced to Fe(II) in solution phase.…”

“…The signals A1, A2 can be attributed to the anodic counterparts of the reduction of Fe(III) minerals (square wave voltammograms display simultaneously cathodic and anodic processes) and/or the oxidation of Fe(II) minerals (such as falayite, gehlenite, etc.) . As judged by blank experiments using different iron minerals, the anodic signal A3 can be mainly assigned to the oxygen evolution catalyzed by crystalline hematite.…”

“…Due to its inherently high sensitivity an essentially non‐invasive sampling the VIMP has been applied for studying different types of cultural heritage . In particular, this technique was previously used for characterizing different iron, lead and manganese species in ceramic materials , composition of raw materials , characterization of and discriminating the production centers of archaeological glasses and Roman and Inka pottery.…”

Untitled

“…X-ray powder diffraction (XRD) and X-ray fluorescence (XRF) are non-destructive methods for the composition analysis of the crystalline materials. Both of the methods are different but complementary to each other whereby XRD is used to analyze the phases or compounds meanwhile XRF is utilized for the analysis of the elemental composition of the crystalline material [95,96]. The analysis of explosive using XRD begun in 1947 with 18 organic explosives were chosen to study their X-ray diffraction pattern [97].…”

Electrochemical methods to discriminate technology and provenance of Apulian red‐figured pottery. II: EIS

“…These are mainly based on the voltammetry of immobilized particles (VIMP), a methodology permitting to extract information from few nanograms of solid sample (Doménech‐Carbó et al, 2013; Scholz & Meyer, 1998; Scholz et al, 2014). This technique has been applied, among other archaeological materials, to ceramic clay bodies (Di Turo et al, 2018; Doménech‐Carbó et al, 2002, 2019; Fabrizzi et al, 2020; Ramaciotti et al, 2020; Sánchez‐Ramos et al, 2002).…”