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- Contribution to the Understanding of the Colour Change in Bluish-Grey LimestonesPublication . Silva, Teresa; De Oliveira, Daniel Pipa Soares; Veiga, JP; Lisboa, Jose; Carvalho, Jorge; Barreiros, M. Alexandra; Coutinho, ML; Salas-Colera, Eduardo; Vigário, RogérioABSTRACT: Bluish-grey limestones have been extensively used as ornamental stones for decoration purposes in buildings, as well as in works of art, and accordingly, have been the target of intense exploration. In Portugal, the Jurassic limestone massif known as the Macico Calcario Estremenho (MCE), has been the source of grey-coloured ornamental stones, namely the Azul Valverde (one of the most well-known bluish-grey limestones) and Atlantic Blue varieties, both of which may undergo colour changes in outdoor environments. In this sense, it is important to understand the sudden colour change from bluish-grey to yellow/beige in the same limestone block in a quarry, or even, what happens to the colour when polished limestone is placed outdoors. This study was undertaken using various techniques, namely XRF (X-ray fluorescence spectrometry), XRD (X-ray diffraction), SEM (scanning electron microscopy), DTA-TG (differential thermal analysis/thermogravimetry) and colourimetry. Synchrotron radiation was also used at the European Synchrotron Radiation Facility (ESRF, Grenoble, France) where XANES (X-ray Absorption Near Edge Structure) spectra at Fe K-edge were collected to ascertain the speciation state of Fe in different coloured zones of the limestone, previously checked by EDXRF (energy dispersive X-ray fluorescence). The presence of Fe2+ and Fe3+ are responsible for the greyish and yellow/brown colour, respectively. On the other hand, the UV radiation from the sun causes a quickened and severe bleaching/fading on the dark blue/grey polished limestone.
- Cultural Heritage analysis using Synchrotron Radiation: case studies in Ceramics, Glasses, and Lithologic MaterialsPublication . Veiga, JP; Coutinho, ML; Figueiredo, Elin; Silva, TeresaABSTRACT: Synchrotron radiaton is a powerful tool for non‐destructve analysis of materials in cultural heritage research. It has revolutonized our ability to understand the compositon, structure, and history of cultural heritage objects, leading to significant advances in fields such as archaeology, art conservation, and materials science. Dedicated beamlines for cultural heritage research are available at synchrotron facilites around the world, such as the European Synchrotron Radiation Facility (ESRF), SOLEIL synchrotron, and ALBA synchrotron, providing specialized support and instrumentation for high‐resolution analysis of cultural heritage objects using various techniques, such as X‐ray absorption spectroscopy, X‐ray fluorescence, X‐ray diffraction, and X‐ray imaging.
- Co and Cu K-edge XANES study of the glazed tiles from the Fronteira Palace (Lisbon, Portugal) [Poster]Publication . Coutinho, ML; Silva, Teresa; Figueiredo, Elin; Rolim, M.; Salas-Colera, Eduardo; Veiga, JPABSTRACT: The Fronteira Palace located in Lisbon was built during the second half of the seventeenth century. The Palace is known for its unique azulejos (Portuguese glazed tiles) dated from the 17th and 18th century which were profusely used both in the interior of the palace and on its magnificent formal gardens. The gardens have a unique cladding of high relief lustre tiles combined with blue-and-white tiles adorning the Gallery of the Kings (Figure 1). Samples of azulejos from Gallery of the Kings, were characterized in a previous work by PIXE. They display a silica alkali-lead glass or silica alkali glass and chromophores based on Co for the blue colouring and Cu for the red-lustre effect . In fact, the analyses showed that the colourless glaze has a lead-alkali silicate composition and a copper-rich lustre overlay, in agreement with the Manise lustreware production (Spain) after the XVII century. To achieve a comparison between manufacturing techniques and pigments used samples were characterized using X-Ray Absorption Spectroscopy. XANES techniques can provide information on the structural behaviour of transition metals in the vitreous matrix - namely, their bonding state and coordination environment, providing relevant information regarding the Co and Cu as chromophores.
- A XANES approach to the blue pigments in ceramic heritage [Resumo]Publication . Coutinho, ML; Veiga, JP; Ruivo, Andreia; Silva, Teresa; Salas-Colera, Eduardo; Bottura Scardina, Silvia; Lima, Augusta; Figueiredo, Elin; Cotte, Marine; Lima, M.M.R.A.
- Decoding Portuguese Azulejos: the intersection of art, history, and science [Resumo]Publication . Veiga, JP; Coutinho, ML; Coentro, S.; Silva, TeresaABSTRACT: In recent decades, the production techniques of azulejos (Portuguese glazed tiles with predominantly blue color) remain a subject of ongoing research. Combining historical research with advanced analytical techniques, this communication aims to show that pigments and materials that define the azulejo colour palette, along with their production recipes and the chemical and structural composition of the glazed tiles. This communication highlights the application of synchrotron radiation to the analysis of Portuguese azulejos. Some examples will be presented, namely the Co and Cu K-edge Xray absorption near-edge spectroscopy (XANES) results performed on glazed tiles from the Fronteira Palace, in Lisbon and the speciation of pigments from Pena National Palace, Sintra. The speciation state of certain chemical elements provides an understanding of their role as chromophores, glass network formers or modifiers, contributing to a deeper knowledge of the production techniques, provenance, and the tiles’ history of use. The non-destructiveness nature allied to the high-resolution capabilities of synchrotron radiation chemical imaging offer a unique tool for investigating cultural heritage materials, enhancing our understanding of their composition, structure, and degradation processes, and contributing to their long-term preservation and interpretation for future conservation efforts.
- Cultural Heritage, Materials Science and Synchrotron Radiation: a perspective from a group of Portuguese usersPublication . Veiga, JP; Coutinho, ML; Silva, Teresa; Figueiredo, Elin; Lima, M.M.R.A.; Saraiva, A.S.; Carvalho, FernandaABSTRACT: In this communication, examples to be presented are related to ancient ceramics, glasses, archaeological slags, inorganic pigments and lithologic materials where we were able to gain new insights into composition, structure and degradation processes, contributing to their preservation and interpretation for future generation.
- An insight into the firing conditions of Chinese blue-and-white porcelain through XANESPublication . Coutinho, ML; Veiga, JP; Ruivo, Andreia; Silva, Teresa; Salas-Colera, Eduardo; Bottura Scardina, Silvia; Lima, Augusta; Figueiredo, Elin; Cotte, Marine; Lima, M.M.R.A.ABSTRACT: Chinese blue-and-white porcelain is found in archaeological excavations worldwide, being significant evidence of global trade routes and cultural exchange. Synchrotron radiation-based techniques have been applied for studying cobalt speciation to establish a correlation between the cobalt and iron oxidation state and local coordination environment in the rich blue shades of Chinese blue-and-white porcelain. However, the relationship between the firing atmosphere conditions and the speciation of cobalt has not been established yet. In this study, underglaze blue models were produced and fired in air or under reducing atmospheres to ascertain the effect of the firing atmosphere in cobalt and iron speciation. The experimental results were compared with data obtained on historical samples of ancient porcelain shards. The microstructure and colour of the produced underglaze blue models were investigated by variable pressure scanning electron microscopy (VP-SEM-EDS), using a hyperspectral imaging camera (Vis-SWIR reflectance spectroscopy) and colorimetry. The formal valence and coordination of cobalt and iron ions of the glaze were determined by X-ray absorption spectroscopy (XAS), particularly X-ray absorption near edge structure (XANES), using synchrotron radiation. Spectral features demonstrated that both cobalt and iron speciation were affected by the firing atmosphere and therefore could be used to ascertain the firing atmosphere.
- A XANES study of the Sn K-edge in slag by-products from tin smelting experiments [Poster]Publication . Figueiredo, Elin; Coutinho, ML; Silva, Teresa; Salas-Colera, Eduardo; Veiga, JPABSTRACT: Tin was a very important alloying element in Western Europe in the production of bronze (Cu-Sn alloy) since the second millennium BC (Bronze Age), when most metallic artefacts were made of this alloy. Smelting experiments using cassiterite collected in the NW Iberian territory were made to produce tin in a very simple and small scale manner, using a small open pit structure to reproduce what could have been the manufacturing process of tin in prehistoric times. Chemical and structural analysis of the products by XRF, SEM-EDS and XRD were made to achieve a detailed knowledge of the characteristics of the materials. Additionally, an X-ray absorption near-edge structure region (XANES) study was performed on three types of slags previously identified (Type 1, Type 2 and Type 3) to obtain information on the oxidation state of Sn. The analyses were made at the European Synchrotron Radiation Facility (ESRF) at the beamline SpLine BM 25A (5-45 keV).
- Characterization of Tableware from Fábrica de Loiça de Sacavém : Linking Analytical and Documental ResearchPublication . Coutinho, ML; Veiga, JP; Ruivo, Andreia; Silva, Teresa; Bottura Scardina, Silvia; Lima, M.M.R.A.; Pereira, Carlos; Dias, Ana Carvalho; Dias, Luis; Vandenabeele, Peter; Roseiro, J. CarlosABSTRACT: Fabrica de Loica de Sacavem (ca. 1858-1994) was among the first to produce white earthenware in Portugal, becoming one of the country's leading ceramic manufacturers during the late 19th to early 20th centuries. Research on white earthenware has accompanied the growing interest in post-industrial archaeology but is still poorly explored compared to more ancient ceramic productions. This study focused on the ceramic body, glazes, and colourants of tableware produced by Fabrica de Loica de Sacavem during the first 50 years of its activity (1859-1910). A multi-analytical approach was selected to investigate the chemical and mineralogical composition of the ceramic body, glaze, and pigments using optical microscopy, variable-pressure scanning electron microscope energy-dispersive X-ray spectroscopy (VP-SEM-EDS), mu-Raman spectroscopy, mu-X-ray Diffraction (mu-XRD), and reflectance spectroscopy (hyperspectral image analysis). The studied tableware was produced with a Ca-poor siliceous-aluminous white earthenware ceramic body covered with transparent alkali lead or lead borosilicate glaze, and most colourants were complex Cr-based pigments. These results are in agreement with the little documental evidence from this period found in the manufacturer's archives.
- From ceramics and glasses to mortars and stones: using synchrotron radiation to study cultural heritage [Poster]Publication . Veiga, JP; Silva, Teresa; Coutinho, MLABSTRACT: The use of Synchrotron Radiation to study cultural heritage, either through objects with museum interest or materials from historical monuments is no longer a novelty. Advanced nondestructive characterization techniques to understand degradation phenomena, ageing mechanisms and ancient manufacturing techniques is now a well-established trend. Profiting from the properties of synchrotron radiation and using large scale facilities such as ESRF (European Synchrotron Radiation Facility, Grenoble, France), BESSY (Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung, Berlin, Germany) and former LURE (Laboratoire pour l’Utilization du Rayonement Synchrotron, Orsay, France), it was possible to study a great diversity of materials and objects of cultural value from different ages and provenances through X-rays. Synchrotron radiation sources available at these large-scale facilities provide powerful chemical and structural characterization tools such as micro X-ray fluorescence and X-ray absorption spectroscopies (XANES and EXAFS). Different case studies will be presented regarding the variety of materials studied by a group of Portuguese researchers from the past two decades (ceramics, glasses, inorganic pigments and lithologic materials).