149 research outputs found
Ateliers métallurgiques dans l'habitat protohistorique du Fort-Harrouard
No full textMohen Jean-Pierre, Aufaure Cécile, Bouet Béatrice, Collin Véronique, Courty Marie-Agnès, Eluère Christiane, Maillard Catherine, Marguerie Dominique, Menu Michel, Queixalos I., Robbiola Luc, Verney Antoine, Walter Philippe. Ateliers métallurgiques dans l'habitat protohistorique du Fort-Harrouard. In: Bulletin de la Société préhistorique française, tome 86, n°10-12, 1989. Du terrain au laboratoire : Pour un meilleur dialogue en archéologie. pp. 404-408
General understanding of outdoor bronze corrosion
No full textThis article aims to enhance the understanding of outdoor bronze alteration in light of a general model, take into account recent developments and according to exposure conditions (sheltered and unsheltered areas). The behaviour of the other alloying elements such as Sn, Zn and Pb is also mentioned. The importance of run-off effects inducing decuprification, the selective copper dissolution of bronze, is underlined on the basis of multi-scale investigation conducted both on natural patinas of outdoor monuments and on corrosion simulation performed in laboratory. A bronze disease affects
outdoor bronze: in sheltered areas, bronze corrosion proceeds from a cyclic phenomenon linked to the repeated action of combined runoff and rainfall events
Inhibiting effects of some Schiff bases on the corrosion of bronze exposed to artificial acidic rain
No full textConservation of artistic heritage is of great importance for the future of the historical and
cultural identity of a society. Both ancient and modern bronze artworks are an important part of this cultural heritage and the production of effective and environmentally satisfactory protective treatments is a central and still unresolved issue. The M-ERA.NET project named B-IMPACT (Bronze-IMproved non-hazardous PAtina CoaTings) operates in this context and aims at developing innovative, eco-friendly and non-hazardous protective coatings for bronze surfaces exposed to the outdoor environment.
This research has the objective to identify new effective bronze corrosion inhibitors for the
future entrapment in surface coatings so giving a contribution to the development of alternative efficient surface treatments.
A number of organic compounds proved to be good corrosion inhibitors for copper [1-5], but mainly azoles, such as triazoles [6-8], tetrazoles [6,9], imidazoles [10] and thiadiazoles [6,9,11], were tested for bronze protection. Mostly benzotriazole (BTA) and triazole derivatives were used and applied in the conservation field [6,8], although there are toxicity and perhaps human carcinogenicity concerns due to their handling and leaching in the environment [12,13]. Some Schiff bases derivatives are claimed to be efficient [1,3,14,15] and environment friendly [1] inhibitors of copper corrosion in acid and neutral chloride solution. For these reasons, some specifically synthesized Schiff bases were tested by electrochemical methods, as BTA alternative inhibitors of bronze corrosion, during exposures to concentrated acidic rain. The inhibition mechanism of the most efficient substance was also studied by surface analyses methods (Scanning Electron Microscope (SEM) observations, Raman and X-Ray Photoelectron Spectroscopy (XPS)
Lingots de plomb et barres de fer des épaves romaines des Saintes-Maries-de-la-Mer (Bouches-du-Rhône, France) : Questions de traçabilité comparée
No full textFerrous and non-ferrous metal provenance studies are always handled in disconnected ways. In spite of two clearly different metallurgies, there are nevertheless some methodological and analytical similarities. It is precisely through the study of two types of metallic materials, lead and iron produced and commercialized during Antiquity, that certain aspects of the tracing will be discussed and compared between ferrous and non-ferrous metals. Through the research of the origin of lead ingots and iron bars of the Roman wrecks of Les Saintes-Maries-de-la-Mer, we shall deal with the importance of the geologic knowledge of ores sources, the notions of heritage, partition and pollution of chemical elements through the metallurgical chaîne opératoire, but also with possible convergences of some analytical developments.Les études de traçabilité des métaux ferreux et non ferreux sont toujours traitées de manière parallèle et imperméable. Malgré deux métallurgies clairement différentes, il existe pourtant des similitudes dans les approches méthodologiques et analytiques. C’est à travers l’étude, justement, de deux types de matériaux métalliques, le plomb et le fer produits et commercialisés dans l’Antiquité, que seront discutés certains aspects de la traçabilité entre ferreux et non ferreux. À travers la recherche de provenance des lingots de plomb et des barres de fer des épaves romaines des Saintes-Maries-de-la-Mer, il sera question de l’importance de la connaissance géologique des minerais sources, des notions d’héritage, de partage et de pollution d’éléments chimiques tout au long de la chaîne opératoire des métaux, mais aussi de possibles convergences de développements analytiques.Baron Sandrine, Coustures Marie-Pierre, Béziat Didier, Guérin Mathilde, Huez Juliette, Robbiola Luc. Lingots de plomb et barres de fer des épaves romaines des Saintes-Maries-de-la-Mer (Bouches-du-Rhône, France) : Questions de traçabilité comparée. In: Revue archéologique de Narbonnaise, tome 44, 2011. pp. 71-97
HISTOIRE D'UNE HACHE A DOUILLE DE L'AGE DU BRONZE OU UNE AUTRE VISION DE LA CORROSION DES BRONZES ARCHEOLOGIQUES
No full textAutorisation ARAAFU (Editeur) en date du 24 juin 2010 (Conseil d'Administration de l'Association) - ref. Mail de MA LInternational audienceThis article describes the main phenomena of alteration of archaeological bronzes. The approach is unconventional, the author has decided to resort to an object in bronze: an ax socket dated from Bronze Age. Several key issues are well addressed through this example. The steps of the archaeological object - from conception to current state - the main surface transformation, the corrosion mechanisms and diagnosis of surface states are in turn described and illustrated.Cet article décrit les principaux phénomènes d'altération des bronzes archéologiques. La démarche suivie est peu conventionnelle, l'auteur ayant décidé de faire parler un objet en bronze : une hache à douille de l'âge du bronze. Plusieurs points essentiels sont ainsi abordés à travers cet exemple. Les étapes de l'objet archéologique - de la conception à l'état actuel -, les principales altérations, les mécanismes de corrosion puis le diagnostic des états de surface sont tour à tour décrits et illustrés
Galvanic corrosion over World War II aircraft wrecks
No full textAluminium usually exhibits a better corrosion resistance than other common metals when exposed to outdoor environments. However, wrecks components made of aluminium alloys, particularly Al-Cu alloys, can be strongly affected by corrosion. The observation of different objects from WWII wrecks indicates more significant degradation in the presence of ferrous parts because of galvanic corrosion.
The study focused on two WWII aircraft objects recovered from French coasts: a Supermarine Spitfire aircraft wing, found in 1988 at sea less than 3 miles from the coast of Plérin, and an aircraft propeller found offshore near the beach of Fécamp. We investigated the galvanic corrosion effect over these
objects and the influence of their Fe/Al areas ratio between the more noble material (usually ferrous
alloy) and the less noble material (usually aluminium alloy). This deterioration was severe due to their exposure to the marine environment and the relatively high amount of Cu (3.4 ‐ 4.5 wt. %) in the Al alloys, provoking pitting, intergranular, and exfoliation corrosion. This study aims to help understanding active corrosion on aircraft wrecks, with the final aim to improve their conservation
Apport de l'analyse statistique des produits de corrosion à la compréhension des processus de dégradation des bronzes archéologiques
No full textThe analysis of the corrosion products of three single phase bronzes, representative of a corpus of Bronze Age objects, was conducted by X-ray microanalysis on a scanning electron microscope. The variations of the main chemical species found in the corrosion products have been characterized. A growth model is suggested to explain the two main corrosion structures observed on archaeological bronzes. The selective dissolution ofthe copper from the alloy can occur via two mechanisms controlled by mass transfer one in relation with the copper cations, and the other one which is dependent on the diffusion of anionic species. A stationnary state is probably reached few decades after the burial. Then, the corrosion process can evoluate locally.L'analyse élémentaire des composés de corrosion de trois bronzes monophasés, représentatifs d'un corpus d'objets de l'Age du Bronze, a été effectuée par microanalyse X sur microscope électronique à balayage. Les variations des teneurs des principaux éléments chimiques dans les couches de corrosion ont été caractérisées. Un modèle de formation des deux principales structures de corrosion des bronzes archéologiques enfouis est proposé. La dissolution sélective du cuivre de Palliagc peut être contrôlée par deux types de processus de transport : l'un, par les cations du cuivre issus de l'oxydation de l'alliage, l'autre par les espèces anioniques de l'électrolyte du sol. Un état stationnaire est probablement atteint après des durées d'enfouissement de quelques dizaines d'années. La corrosion n'évolue alors que localement sur l'objet.Robbiola Luc, Fiaud Christian. Apport de l'analyse statistique des produits de corrosion à la compréhension des processus de dégradation des bronzes archéologiques. In: Revue d'Archéométrie, n°16, 1992. pp. 109-119
Bijoux de l´élite du haut Moyen âge en Grande-Moravie et Bohême : technique de fabrication, montage, matériaux et état de conservation
No full textAu début du IXème siècle, en Europe centrale, des parures somptueuses sans précédents apparaissent dans les tombes de l´élite de la Grande Moravie, le premier pré-état slave du IXème siècle, en quantité et variété considérables. Ces ornements connaissent un essor spectaculaire et seront adoptés par les élites de Bohême jusqu´au Xème siècle. L´étude technologique détaillée de ces bijoux a permis une meilleure compréhension technologique de ces pièces. Elle a montré que ces objets étaient des artefacts très complexes, composés de multiples éléments assemblés et dont la production mettait en œuvre plusieurs techniques de mise en forme et de décoration très sophistiquées telles que la granulation, le travail en filigrane, la ciselure et la dorure. Elle a apporté des éléments de comparaison complémentaires à l'approche typologique et thématique classique. Le choix du matériau, les étapes de fabrication, les techniques de décoration, les modèles de montage, la taille des différents éléments constitutifs et décoratifs assemblés ou les marques d'outillage se sont révélés être des marqueurs précieux de la qualité de réalisation, permettant d’aborder la production d'ateliers spécifiques, le transfert de technologie, l'identification d´importations éventuelles, et enfin, d´éventuelles influences. Cette étude a montré en outre que différents matériaux précieux (or, argent et cuivre dorés) de pureté variable ont été utilisés pour fabriquer ces bijoux et que des alliages de différentes compositions avaient été utilisés selon les régions concernées et au fil du temps. Ce travail a également mis en évidence la présence, en Moravie et en Bohême, de bijoux d´une très grande finesse réalisés par des orfèvres hautement qualifiés et la présence d´imitations de moindre qualité, produites par des artisans locaux moins expérimentés révélant ce faisant un processus de transfert de technologie qui s´est sans doute opéré suite à l´arrivée d´orfèvres spécialisés en Moravie et en Bohême.At the beginning of the 9th century, in central Europe, unparalleled lavish pieces of jewellery appear in elite graves from Great Moravia, the first Slavic pre-dominion, in incredible amount and variety. The detailed technological investigation of these jewels performed in this thesis, permitted a better understanding of these objects. This investigation showed that these jewels are very complex, multi-component artefacts, which demanded the fabrication and joining of numerous components as well as very sophisticated techniques of decoration, such as granulation, filigree work, chasing, and gilding. It brought useful additional elements in comparison to the classical typological and thematical approaches. Thus, the choice of material, the different steps of fabrication, the decorative techniques, construction pattern, the size of different constitutive and decorative components assembled, tool marks, and the quality of realization are all very valuable archaeological markers, which were used to identify production from specific workshops, the transfer of technology, probable imports, and influences. In addition, the study revealed that different precious materials (gold, silver, and gilded copper) of variable purity were used in the production of the jewellery and that the compositions of the alloys varied between the different regions and over the course of time. It also evidenced that fine jewels produced by highly skilled and knowledgeable jewellers coexisted with more coarsely manufactured imitations produced by less experienced craftsmen, which reveals a process of new technology acquisition likely initiated by the arrival of specialized jewellers to both Moravia and Bohemia
Corrosion protection of outdoor bronze: historical quaternary alloy and modern alloy with artificial patination
No full textOutdoor bronzes suffer corrosion phenomena that generate partially protecting layers called patina. In urban atmosphere, the action of the environment makes these patinas partially leached away by rainwater. Moreover, the geometry of exposure influences the corrosion behaviour: in particular, different kinds of patinas are formed in “sheltered” or “unsheltered” areas due to the action of acid rain. These two kinds of patina were simulated through dropping (runoff) and wet&dry (stagnant rain) testing devices in order to obtain representative substrates for the application of protective coatings. However, when considering representative substrates for the application of protective coatings, also artificial patinas such as “liver of sulphur” (based on the use of sulphide solutions), frequently applied by artistic foundries, should be taken into account. The present work reports on chemical and morphological characterisation of (i) historical quaternary bronze (Cu-Sn-Zn-Pb), pre-patinated by artificial ageing (both by dropping and wet&dry tests) and (ii) K2S artificially pre-patinated modern bronze (Cu-Si-Mn), with and without silane-based coatings formulated during the EU-project B-IMPACT
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