Philippe Dillmann | Centre National de la Recherche Scientifique / French National Centre for Scientific Research (original) (raw)

Papers by Philippe Dillmann

International Journal of Architectural Heritage, 2019

This article presents an overview of the metallographic structures observed on the iron reinforce... more This article presents an overview of the metallographic structures observed on the iron reinforcements of more than 20 buildings from the medieval and modern period in France, which are representative of the evolution of ironmaking techniques at that time (330 samples). Metallographic examinations show a great diversity of structures, even in the same sample: pure ferritic iron to low pearlitic steel, presence of phosphorus in solid solution (locally up to 0.5%wt), numerous slag inclusions of various sizes, porosities. Tensile tests were performed on a representative set of samples from 4 buildings (46 samples). The results are in accordance with the metallographic observations: mechanical behaviors are very heterogeneous, even in samples taken on the same artefact. Failure happened at values as low as the yield stress up to 25% of the plastic strain. These reinforcements probably worked in the elastic domain at low stress (<150 Mpa). These mechanical properties are significantly beyond those of modern carbon steels and question the exact role of iron in the stability of monuments. ARTICLE HISTORY

Iron was included in the initial design of most gothic churches. Many tons of iron bars were used... more Iron was included in the initial design of most gothic churches. Many tons of iron bars were used in stained glass windows; iron structural rods and chains were used in masonry and frameworks, and smaller pieces such as cramps and pins were used to attach numerous sculpted ornaments. Many questions arise regarding the use of iron in medieval construction: the quantities used by the master builders, the location, supply and cost, the nature and quality of the ferrous alloys employed and the influence of changes in medieval iron production, notably the introduction of water-powered hammers and blast furnaces. In this research, important medieval churches in Rouen and Troyes were investigated. Medieval account books were studied, and metallographic analyses were carried out on 74 iron pieces sampled in the buildings. This paper presents the methods and the results of this interdisciplinary work.

La construction du beffroi de la ville de Metz (Moselle, France), entre 1478 et 1483, a nécessité... more La construction du beffroi de la ville de Metz (Moselle, France), entre 1478 et 1483, a nécessité l'utilisation de plusieurs centaines de renforts ferreux afin de contribuer à la cohésion de la maçonnerie. Ce chantier se déroule à un moment particulier de l'histoire de la sidérurgie européenne, marqué par la diffusion du procédé indirect. Cette filière technique est adoptée graduellement par les producteurs de métal, définissant un panorama sidérurgique particulièrement riche et varié, dont l'étude enrichit notre perception de l'histoire de l'économie et des techniques métallurgiques. Une étude archéométrique extensive a été réalisée sur les renforts et leurs scellements en plomb afin de déterminer les origines technique et géographique du fer utilisé. L'exploitation des données chimiques obtenues a nécessité l'utilisation de plusieurs analyses statistiques multivariées afin de mieux comprendre l'histoire de l'édifice, d'évaluer l'importance du fer produit par procédé indirect sur les marchés du fer lorrains de la fin du Moyen Âge, et d'identifier les acteurs sidérurgiques engagés dans l'approvisionnement des réseaux d'échange. Cet article présente les étapes successives de l'étude réalisée, en détaillant pour chacune les facteurs qui ont motivé le recours à différentes analyses statistiques multivariées (analyse en composantes principales, classification ascendante hiérarchique, régression logistique), ainsi que les principaux résultats obtenus. Abstract: The building of the belfry of Metz (Lorraine, France), which took place between 1478 and 1483, necessitated the implementation of hundreds of ferrous reinforcements to contribute to the cohesion of the masonry. This building yard took place at a particular time in the history of the European siderurgy, marked by the diffusion of the finery process. This technical innovation has been gradually adopted par iron producers, drawing up a particularly rich and diverse panorama, whose study enrichises our knowledge of the history of metallurgical techniques and economy. An extensive archaeometrical study was carried out on the reinforcements and their lead sealings in order to determine the technical and geographical origins of the iron. The processing of the chemical data that was obtained required the use of several multivariate statistical analyses to better understand the chronology of the monument, to evaluate the importance of the finery process in the supply of the iron markets set up in late medieval Lorraine, and to identify the iron producers involved in providing the exchange networks. This paper presents the successive stages of the study, by detailing for each step the factors that have required the use of different multivariate statistical analyses (principal component analysis, hierarchical clustering, logistic regression), as well as the major results obtained.

Os isotopic ratios and trace element approaches were used to compare the signatures of ore and sl... more Os isotopic ratios and trace element approaches were used to compare the signatures of ore and slag from different potential production sites located in eastern France and SouthWest Germany with the signature of artefacts from the end of the first Iron Age. A set of 31 artefacts was tested, consisting of bipyramidal semi-products, chariot tires, blooms and other commodities. The complementarity of the two approaches is demonstrated. Bipartite bipyramidal semi-products made by assembling two crude masses of distinct origins are evidenced suggesting the existence of intermediate producing centres assembling products from different origins. Only the provenance of blooms and wheel-tires could be established as local. Two spheres of metal circulation were evidenced: prestige and local. Bipyramidal semi-products and chariot tires belong to different long distance distribution networks.

Corrosion Engineering, Science and Technology, 2017

A carbon steel container including nuclear glass has been altered for 2 years in Andra?s Undergro... more A carbon steel container including nuclear glass has been altered for 2 years in Andra?s Underground Research Laboratory to simulate the behaviour of waste package. Post-mortem analyses at different scales (macro?micro?nano) have been performed to identify neoformed phases on iron corrosion products (ICP) and in the glass alteration layer (GAL). It has been shown at nanometric scale that important quantities of iron and silicon were found in the GAL and in the ICP respectively. Using a comparative approach with phyllosilicate references, STXM, at Si-K edge, suggests presence of trioctahedral species in the GAL and in ICP. Relevant fits of the STXM spectra are obtained with a Fe-rich chlorite for the nanostructured GAL, which could be formed according to chloritisation mechanism.This paper is part of a supplement on the 6th International Workshop on Long-Term Prediction of Corrosion Damage in Nuclear Waste Systems.

Introduction Les sciences archéologiques 1 , telles que nous les considérons dans cet ouvrage, s'... more Introduction Les sciences archéologiques 1 , telles que nous les considérons dans cet ouvrage, s'in-téressent aux informations enregistrées par les objets archéologiques ou du patri-moine, artefacts ou archives environnementales, à différentes échelles (du nanomètre à l'échelle macroscopique), le plus souvent observables à travers la mesure instrumen-tée de paramètres inaccessibles à l'observation visuelle. Par essence, elles constituent un domaine de recherche fortement interdisciplinaire. Elles emploient des méthodes relevant des sciences chimiques et physiques, sciences de la Terre et de la vie et des sciences environnementales. Le but des recherches est principalement à finalité histo-rique. La démarche est pleinement intégrée aux problématiques archéologiques qui ont pour objet principal de comprendre les modes de vie des populations anciennes, les pratiques sociales, culturelles, économiques et techniques ainsi que leur relation à l'en-vironnement. Nous englobons également, dans une acception large, les thématiques liées à la conservation des objets et des monuments du patrimoine et qui nécessitent de comprendre finement les processus d'altération, afin de les maîtriser voire de les stopper mais également de collecter des informations sur l'état initial de l'objet lors de son abandon, avant la mise en route de ces processus d'altération. À ce titre ces problématiques rejoignent celles de la taphonomie qui s'intéresse, elle, aux proces-sus de dégradation des organismes vivants après leur mort et leur enfouissement. En France, la communauté de chercheurs liée à ce domaine est représentée notamment par le réseau CAI-RN « Compétences Archéométriques Interdisciplinaires – Réseau National » de la Mission pour l'Interdisciplinarité du CNRS 2 .

Archaeometry, 2017

In the early days of iron metallurgy in Western Europe, the most widespread type of 'trade iron' ... more In the early days of iron metallurgy in Western Europe, the most widespread type of 'trade iron' (semi-product) was bipyramidal in shape. Although they are frequently found, little is known about how they were manufactured and circulated, or even about their age. An interdisciplinary approach was applied to the Durrenentzen deposit (Haut-Rhin, France), the third-largest in Europe in terms of artefact quantities, in an attempt to reconstruct the technological, social and economic context that caused them to be abandoned. A morphometric study of the 51 iron bars revealed a high degree of homogeneity, despite variations in detail. Four objects were selected for archaeometric studies. Metallographic analyses show internal differences (quality of the material, nature of the alloys and manufacturing techniques). Chemical analyses also showed different provenances. Finally, radiocarbon analyses of the carbon in steel (iron/carbon alloy) linked this deposit to the early Iron Age. This study provided the first benchmark for more general research, significantly changing perceptions of the economics of iron at the beginning of the Iron Age.

Cet article présente l'apport des méthodes archéométriques à la réflexion en histoire des techniq... more Cet article présente l'apport des méthodes archéométriques à la réflexion en histoire des techniques. Il prend pour sujet la métallurgie des métaux ferreux pour laquelle une mutation importante des filières techniques apparaît et se répand dans le nord de l'Europe entre la fin du Moyen Âge et le début de l'époque moderne. L'analyse des fers de renfort employés dans les grands monuments religieux et civils construits à cette période a permis de pister l'apparition et la diffusion du procédé indirect pour la fabrication de ces produits métalliques. Elle montre pour ce marché un rythme de diffusion du nouveau procédé différent de celui que révèlent les sources écrites pour la production du métal. Ces résultats interrogent la nature spécifique de ce marché mais également celle de la diffusion de l'innovation liée à l'apparition du nouveau procédé. Abstract. Archaeometry and history of technonogy : direct and indirect processes in iron metallurgy (14th-17th centuries) This paper aims to present the contribution of archaeometric approaches to the reflexion in history of technology. This will be illustrated by the case of ferrous metals. Between the end of the Middle Ages and the beginning of the modern period, a new ironmaking process appeared and spread in the north of Europe. The analysis of reinforcing ferrous elements employed for the building of religious and civil monuments at this period allowed us to follow the diffusion of

Reinforcing clamps made of low alloy steel from the Metz cathedral and corroded outdoors during 5... more Reinforcing clamps made of low alloy steel from the Metz cathedral and corroded outdoors during 500 years were studied by OM, FESEM/EDS, and micro-Raman spectroscopy. The corrosion product layer is constituted of a dual structure. The outer layer is mainly constituted of goethite and lepidocrocite embedding exogenous elements such as Ca and P. The inner layer is mainly constituted of ferrihydrite. The behaviour of the inner layer under conditions simulating the wetting stage of the RH wet/dry atmospheric corrosion cycle was observed by in situ micro-Raman spectroscopy. The disappearance of ferrihydrite near the metal/oxide interface strongly suggests a mechanism of reductive dissolution caused by the oxidation of the metallic substrate and was observed for the first time in situ on an archaeological system.

Dans plusieurs domaines appliqués, on désire comprendre et modéliser la corrosion des aciers doux... more Dans plusieurs domaines appliqués, on désire comprendre et modéliser la corrosion des aciers doux sur de très longues durées, dépassant largement le siècle. Pour ce faire, la compréhension des mécanismes à différentes échelles – de l'échelle fonctionnelle au nanomètre – est nécessaire. Cet article montre comment la mise en oeuvre de techniques de caractérisation à l'échelle submicrométrique permet la compréhension de ces mécanismes, notamment à l'issue d'expériences de remise en corrosion de systèmes analogues en milieux marqués. Les techniques évoquées sont en particulier la microscopie électronique (FESEM, MET), la spectroscopie d'absorption des rayons X sous rayonnement synchrotron (STXM) et les spectrométries de masse (nanoSIMS). Abstract Analysis at micro and nanometric scales of long-term corroded low alloy steels and glasses In several domains of applied research, it is necessary to understand and model the corrosion of low alloy steels during very long periods, sometimes more than several centuries. To that purpose, the understanding of mechanisms at different scales is crucial. This paper shows how the implementation of characterisation techniques at sub-micrometric scales allows to understand these mechanisms. The techniques evocated here are: electronic microscopy (FESEM, TEM), X-ray absorption spectrometry under synchrotron radiation (STXM) and mass spectrometry (nanoSIMS) applied after isotopic labelling.

Two tests of iron corrosion in compacted clay and clay slurry were performed for several years. T... more Two tests of iron corrosion in compacted clay and clay slurry were performed for several years. The corrosion systems, and especially the interfacial layer between the metal and the corrosion products, were investigated post mortem by SEM-FEG, mRaman, MET and STXM. An Fe(III) oxide layer systematically developed at a nanometer scale between the metal and an outer layer of carbonates. Its presence could explain the slowing down of the corrosion rate usually observed for these systems. Depending of the compactness of the environment the nature of the interfacial layer is not the same.

Large quantities of iron reinforcements, found in most Gothic monuments, are a data source for th... more Large quantities of iron reinforcements, found in most Gothic monuments, are a data source for the interpretation of medieval architecture however their role both in contemporary engineering theory and the technical reality of construction yards has not yet been specified due to the difficulty of directly dating them. We present here an original radiocarbon dating methodology to date metal itself. Radio-carbon dates were measured for iron reinforcements used in specific parts of Bourges and Beauvais cathedrals, two iconic buildings in the development of French gothic architecture. Coupled with archaeometric and archaeological data, the new chronological results illuminate the major and active roles played by iron in the strategy of the building yards. At Bourges, iron was assimilated into the ca-thedral's construction strategy, whereas at Beauvais iron was integrated from the initial design, added to the monument following the vicissitudes of the building yard, and still used during the modern period. Thus, through decisive advances in radiocarbon dating of iron artefacts, the evolution of medieval architectural and engineering thought and action has been more reliably reconstructed.

Architecture represents key evidence of dynastic practice and change in the archaeological world.... more Architecture represents key evidence of dynastic practice and change in the archaeological world. Chronologies for many important buildings and sequences, including the iconic temples of medieval Angkor in Cambodia, are based solely on indirect associations from inscriptions and architectural styles. The Baphuon temple, one of the last major buildings in Angkor without textual or scientifically-derived chronological evidence, is crucial both for the context and date of its construction and the period when its western façade was modified into a unique, gigantic Reclining Buddha. Its construction was part of a major dynastic change and florescence of the Hindu-Mahayana Buddhist state and the modification is the key evidence of Theravada Buddhist power after Angkor's decline in the 15 th century. Using a newly-developed approach based on AMS radiocarbon dating to directly date four iron crampons integrated into the structure we present the first direct evidence for the history of the Baphuon. Comprehensive study of ferrous elements shows that both construction and modification were critically earlier than expected. The Baphuon can now be considered as the major temple associated with the imperial reformations and territorial consolidation of Suryavarman I (1010–1050 AD) for whom no previous building to legitimize his reign could be identified. The Theravada Buddhist modification is a hundred years prior to the conventional 16 th century estimation and is not associated with renewed use of Angkor. Instead it relates to the enigmatic Ayutthayan occupation of Angkor in the 1430s and 40s during a major period of climatic instability. Accurately dating iron with relatively low carbon content is a decisive step to test long-standing assumptions about architectural histories and political processes for states that incorporated iron into buildings (e.g., Ancient Greece, medieval India). Furthermore, this new approach has the potential to revise chronologies related to iron consumption practices since the origins of ferrous metallurgy three millennia ago.

This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/authorsrights a b s t r a c t A specific statistical approach was tested to determine the ironmaking processes (bloomery or indirect) used to manufacture iron reinforcements found in two French gothic medieval monuments: Metz and Beauvais Cathedrals. Slag inclusions embedded in the metallic matrix were analysed and the major element compositions were quantified, using a Si Drift EDS detector permitting the study of several hundred inclusions per artefact. First, pre-processing was applied to the raw data to discriminate inclusions from the smelting stage (or refining stage for the indirect process) from those formed during post-reduction operations (forging etc.). PCA and hierarchical clustering on the major element compositions were then performed. Secondly, a specific multivariate statistical method, logistic regression, was applied to a learning set of data from a reference set of samples. This allowed the development of a model capable of distinguishing artefacts from the two smelting processes and to link unknown samples to one or the other. This model was then used to study artefacts from the Mutte Tower of Metz Cathedral and Beauvais Cathedral. This allowed us to confirm the extensive use of iron reinforcements since the construction of Beauvais cathedral. In the Mutte Tower of Metz Cathedral clamps from Lorraine reinforced some parts of the monument from its construction between the 13th and the 15th centuries.

This paper develops new reflections regarding the provenance of iron artefacts, by defining the t... more This paper develops new reflections regarding the provenance of iron artefacts, by defining the trade networks that might have supplied the building yard of the Metz city belfry at the end of the 15th century. Regional field surveys were carried out in Lorraine in order to constitute a chemical repository, including ironmaking zones considered as the most probable metal providers. The chemical characterization—both major and trace elements—of slag inclusions entrapped in the metallic matrix of iron reinforcements was performed in order to compare their chemical signature to the reference set. A statistical approach based on the combined use of descriptive multivariate analyses was developed to infer the origin of the metal supplied to the building yard. As the multiplicity of potential metal providers was assessed from former studies, the results obtained underline the place taken by local workshops in the supply strategy developed by the builders. This study thus provides crucial information supporting a discussion about the scale and the organization of such networks at the end of the Middle Ages.

Iron sulphides are observed on long term anoxic corrosion profiles of iron artefacts. The archaeo... more Iron sulphides are observed on long term anoxic corrosion profiles of iron artefacts. The archaeological nails studied came from two terrestrial sites (Glinet and Raadhuspladsen) and a subaquatic one (Arles-Rhône 3). Greigite (Fe 3 S 4) and/or mackinawite (FeS 1−x) are observed at the outer border of the corrosion product layer. The presence of mackinawite is discussed relatively to the establishment of stable anoxic burial conditions. The nails from the subaquatic site present pyrite globules in the transformed medium. The formation of pyrite (FeS 2) is attributed to the proximity of wood. The iron sulphides formation may also be explained by the presence of sulphate-reducing bacteria in the burial environment.

Glass long term alteration in the context of high-level radioactive waste (HLW) storage is influe... more Glass long term alteration in the context of high-level radioactive waste (HLW) storage is influenced by near-field materials and environmental context. As previous studies have shown, the extent of glass alteration is strongly related to the presence of iron in the system, mainly provided by the steel overpack around surrounding the HLW glass package. A key to understanding what will happen to the glass-borne elements in the geological disposal lies in the relationship between the iron-bearing phases and the glass alteration products formed. In this study, we focus on the influence of the formation conditions (synthetized or in-situ) and the age of different iron corrosion products on SON68 glass alteration. Corrosion products obtained from archaeological iron artifacts are considered here to be true analogues of the corrosion products in a waste disposal system due to the similarities in formation conditions and physical properties. These representative corrosion products (RCP) are used in the experiment along with synthetized iron anoxic corrosion products and pristine metallic iron. The model-cracks of SON68 glass were altered in cell reactors, with one of the different iron-sources inserted in the crack each time. The study was successful in reproducing most of the processes observed in the long term archaeological system. Between the different systems, alteration variations were noted both in nature and intensity, confirming the influence of the iron-source on glass alteration. Results seem to point to a lesser effect of long term iron corrosion products (RCP) on the glass alteration than that of the more recent products (SCP), both in terms of general glass alteration and of iron transport.

In the context of conservation of ferrous cultural heritage, dechlorination processes of archaeol... more In the context of conservation of ferrous cultural heritage, dechlorination processes of archaeological iron artefacts are studied in subcritical conditions which consist of immerging an artefact inside an alkaline bath under pressure (30 bar) and temperature (160 8C). Submarine archaeological environments lead to the presence of chlorides inside the corrosion layers. After exposure to the atmosphere following excavation, initial corrosion phases evolve. Chlorides remain trapped inside the structure of corrosion products particularly during the crystallisation of akaganeite. Stabilisation treatment objectives are to remove chlorides from the corrosion layers and to obtain more stable phases. A Roman archaeological bar has been studied on cross-section before and after treatment in sub-critical conditions. Less stable phases, such as ferrihydrite and akaganeite, transformed into hematite. That was confirmed by the use of synthetic and pure phases treated in the same conditions. The presence of goethite before and after the treatment in the corrosion profile raises the question of its reactivity during dechlorination process. Akaganeite has been synthesised and compared to archaeological powder sampled on an artefact. The results highlight reactivity differences indicating that sub-critical transformation processes are not only dependent on the nature of phases but also on intrinsic physical characteristics.

International Journal of Architectural Heritage, 2019

This article presents an overview of the metallographic structures observed on the iron reinforce... more This article presents an overview of the metallographic structures observed on the iron reinforcements of more than 20 buildings from the medieval and modern period in France, which are representative of the evolution of ironmaking techniques at that time (330 samples). Metallographic examinations show a great diversity of structures, even in the same sample: pure ferritic iron to low pearlitic steel, presence of phosphorus in solid solution (locally up to 0.5%wt), numerous slag inclusions of various sizes, porosities. Tensile tests were performed on a representative set of samples from 4 buildings (46 samples). The results are in accordance with the metallographic observations: mechanical behaviors are very heterogeneous, even in samples taken on the same artefact. Failure happened at values as low as the yield stress up to 25% of the plastic strain. These reinforcements probably worked in the elastic domain at low stress (<150 Mpa). These mechanical properties are significantly beyond those of modern carbon steels and question the exact role of iron in the stability of monuments. ARTICLE HISTORY

Iron was included in the initial design of most gothic churches. Many tons of iron bars were used... more Iron was included in the initial design of most gothic churches. Many tons of iron bars were used in stained glass windows; iron structural rods and chains were used in masonry and frameworks, and smaller pieces such as cramps and pins were used to attach numerous sculpted ornaments. Many questions arise regarding the use of iron in medieval construction: the quantities used by the master builders, the location, supply and cost, the nature and quality of the ferrous alloys employed and the influence of changes in medieval iron production, notably the introduction of water-powered hammers and blast furnaces. In this research, important medieval churches in Rouen and Troyes were investigated. Medieval account books were studied, and metallographic analyses were carried out on 74 iron pieces sampled in the buildings. This paper presents the methods and the results of this interdisciplinary work.

La construction du beffroi de la ville de Metz (Moselle, France), entre 1478 et 1483, a nécessité... more La construction du beffroi de la ville de Metz (Moselle, France), entre 1478 et 1483, a nécessité l'utilisation de plusieurs centaines de renforts ferreux afin de contribuer à la cohésion de la maçonnerie. Ce chantier se déroule à un moment particulier de l'histoire de la sidérurgie européenne, marqué par la diffusion du procédé indirect. Cette filière technique est adoptée graduellement par les producteurs de métal, définissant un panorama sidérurgique particulièrement riche et varié, dont l'étude enrichit notre perception de l'histoire de l'économie et des techniques métallurgiques. Une étude archéométrique extensive a été réalisée sur les renforts et leurs scellements en plomb afin de déterminer les origines technique et géographique du fer utilisé. L'exploitation des données chimiques obtenues a nécessité l'utilisation de plusieurs analyses statistiques multivariées afin de mieux comprendre l'histoire de l'édifice, d'évaluer l'importance du fer produit par procédé indirect sur les marchés du fer lorrains de la fin du Moyen Âge, et d'identifier les acteurs sidérurgiques engagés dans l'approvisionnement des réseaux d'échange. Cet article présente les étapes successives de l'étude réalisée, en détaillant pour chacune les facteurs qui ont motivé le recours à différentes analyses statistiques multivariées (analyse en composantes principales, classification ascendante hiérarchique, régression logistique), ainsi que les principaux résultats obtenus. Abstract: The building of the belfry of Metz (Lorraine, France), which took place between 1478 and 1483, necessitated the implementation of hundreds of ferrous reinforcements to contribute to the cohesion of the masonry. This building yard took place at a particular time in the history of the European siderurgy, marked by the diffusion of the finery process. This technical innovation has been gradually adopted par iron producers, drawing up a particularly rich and diverse panorama, whose study enrichises our knowledge of the history of metallurgical techniques and economy. An extensive archaeometrical study was carried out on the reinforcements and their lead sealings in order to determine the technical and geographical origins of the iron. The processing of the chemical data that was obtained required the use of several multivariate statistical analyses to better understand the chronology of the monument, to evaluate the importance of the finery process in the supply of the iron markets set up in late medieval Lorraine, and to identify the iron producers involved in providing the exchange networks. This paper presents the successive stages of the study, by detailing for each step the factors that have required the use of different multivariate statistical analyses (principal component analysis, hierarchical clustering, logistic regression), as well as the major results obtained.

Os isotopic ratios and trace element approaches were used to compare the signatures of ore and sl... more Os isotopic ratios and trace element approaches were used to compare the signatures of ore and slag from different potential production sites located in eastern France and SouthWest Germany with the signature of artefacts from the end of the first Iron Age. A set of 31 artefacts was tested, consisting of bipyramidal semi-products, chariot tires, blooms and other commodities. The complementarity of the two approaches is demonstrated. Bipartite bipyramidal semi-products made by assembling two crude masses of distinct origins are evidenced suggesting the existence of intermediate producing centres assembling products from different origins. Only the provenance of blooms and wheel-tires could be established as local. Two spheres of metal circulation were evidenced: prestige and local. Bipyramidal semi-products and chariot tires belong to different long distance distribution networks.

Corrosion Engineering, Science and Technology, 2017

A carbon steel container including nuclear glass has been altered for 2 years in Andra?s Undergro... more A carbon steel container including nuclear glass has been altered for 2 years in Andra?s Underground Research Laboratory to simulate the behaviour of waste package. Post-mortem analyses at different scales (macro?micro?nano) have been performed to identify neoformed phases on iron corrosion products (ICP) and in the glass alteration layer (GAL). It has been shown at nanometric scale that important quantities of iron and silicon were found in the GAL and in the ICP respectively. Using a comparative approach with phyllosilicate references, STXM, at Si-K edge, suggests presence of trioctahedral species in the GAL and in ICP. Relevant fits of the STXM spectra are obtained with a Fe-rich chlorite for the nanostructured GAL, which could be formed according to chloritisation mechanism.This paper is part of a supplement on the 6th International Workshop on Long-Term Prediction of Corrosion Damage in Nuclear Waste Systems.

Introduction Les sciences archéologiques 1 , telles que nous les considérons dans cet ouvrage, s'... more Introduction Les sciences archéologiques 1 , telles que nous les considérons dans cet ouvrage, s'in-téressent aux informations enregistrées par les objets archéologiques ou du patri-moine, artefacts ou archives environnementales, à différentes échelles (du nanomètre à l'échelle macroscopique), le plus souvent observables à travers la mesure instrumen-tée de paramètres inaccessibles à l'observation visuelle. Par essence, elles constituent un domaine de recherche fortement interdisciplinaire. Elles emploient des méthodes relevant des sciences chimiques et physiques, sciences de la Terre et de la vie et des sciences environnementales. Le but des recherches est principalement à finalité histo-rique. La démarche est pleinement intégrée aux problématiques archéologiques qui ont pour objet principal de comprendre les modes de vie des populations anciennes, les pratiques sociales, culturelles, économiques et techniques ainsi que leur relation à l'en-vironnement. Nous englobons également, dans une acception large, les thématiques liées à la conservation des objets et des monuments du patrimoine et qui nécessitent de comprendre finement les processus d'altération, afin de les maîtriser voire de les stopper mais également de collecter des informations sur l'état initial de l'objet lors de son abandon, avant la mise en route de ces processus d'altération. À ce titre ces problématiques rejoignent celles de la taphonomie qui s'intéresse, elle, aux proces-sus de dégradation des organismes vivants après leur mort et leur enfouissement. En France, la communauté de chercheurs liée à ce domaine est représentée notamment par le réseau CAI-RN « Compétences Archéométriques Interdisciplinaires – Réseau National » de la Mission pour l'Interdisciplinarité du CNRS 2 .

Archaeometry, 2017

In the early days of iron metallurgy in Western Europe, the most widespread type of 'trade iron' ... more In the early days of iron metallurgy in Western Europe, the most widespread type of 'trade iron' (semi-product) was bipyramidal in shape. Although they are frequently found, little is known about how they were manufactured and circulated, or even about their age. An interdisciplinary approach was applied to the Durrenentzen deposit (Haut-Rhin, France), the third-largest in Europe in terms of artefact quantities, in an attempt to reconstruct the technological, social and economic context that caused them to be abandoned. A morphometric study of the 51 iron bars revealed a high degree of homogeneity, despite variations in detail. Four objects were selected for archaeometric studies. Metallographic analyses show internal differences (quality of the material, nature of the alloys and manufacturing techniques). Chemical analyses also showed different provenances. Finally, radiocarbon analyses of the carbon in steel (iron/carbon alloy) linked this deposit to the early Iron Age. This study provided the first benchmark for more general research, significantly changing perceptions of the economics of iron at the beginning of the Iron Age.

Cet article présente l'apport des méthodes archéométriques à la réflexion en histoire des techniq... more Cet article présente l'apport des méthodes archéométriques à la réflexion en histoire des techniques. Il prend pour sujet la métallurgie des métaux ferreux pour laquelle une mutation importante des filières techniques apparaît et se répand dans le nord de l'Europe entre la fin du Moyen Âge et le début de l'époque moderne. L'analyse des fers de renfort employés dans les grands monuments religieux et civils construits à cette période a permis de pister l'apparition et la diffusion du procédé indirect pour la fabrication de ces produits métalliques. Elle montre pour ce marché un rythme de diffusion du nouveau procédé différent de celui que révèlent les sources écrites pour la production du métal. Ces résultats interrogent la nature spécifique de ce marché mais également celle de la diffusion de l'innovation liée à l'apparition du nouveau procédé. Abstract. Archaeometry and history of technonogy : direct and indirect processes in iron metallurgy (14th-17th centuries) This paper aims to present the contribution of archaeometric approaches to the reflexion in history of technology. This will be illustrated by the case of ferrous metals. Between the end of the Middle Ages and the beginning of the modern period, a new ironmaking process appeared and spread in the north of Europe. The analysis of reinforcing ferrous elements employed for the building of religious and civil monuments at this period allowed us to follow the diffusion of

Reinforcing clamps made of low alloy steel from the Metz cathedral and corroded outdoors during 5... more Reinforcing clamps made of low alloy steel from the Metz cathedral and corroded outdoors during 500 years were studied by OM, FESEM/EDS, and micro-Raman spectroscopy. The corrosion product layer is constituted of a dual structure. The outer layer is mainly constituted of goethite and lepidocrocite embedding exogenous elements such as Ca and P. The inner layer is mainly constituted of ferrihydrite. The behaviour of the inner layer under conditions simulating the wetting stage of the RH wet/dry atmospheric corrosion cycle was observed by in situ micro-Raman spectroscopy. The disappearance of ferrihydrite near the metal/oxide interface strongly suggests a mechanism of reductive dissolution caused by the oxidation of the metallic substrate and was observed for the first time in situ on an archaeological system.

Dans plusieurs domaines appliqués, on désire comprendre et modéliser la corrosion des aciers doux... more Dans plusieurs domaines appliqués, on désire comprendre et modéliser la corrosion des aciers doux sur de très longues durées, dépassant largement le siècle. Pour ce faire, la compréhension des mécanismes à différentes échelles – de l'échelle fonctionnelle au nanomètre – est nécessaire. Cet article montre comment la mise en oeuvre de techniques de caractérisation à l'échelle submicrométrique permet la compréhension de ces mécanismes, notamment à l'issue d'expériences de remise en corrosion de systèmes analogues en milieux marqués. Les techniques évoquées sont en particulier la microscopie électronique (FESEM, MET), la spectroscopie d'absorption des rayons X sous rayonnement synchrotron (STXM) et les spectrométries de masse (nanoSIMS). Abstract Analysis at micro and nanometric scales of long-term corroded low alloy steels and glasses In several domains of applied research, it is necessary to understand and model the corrosion of low alloy steels during very long periods, sometimes more than several centuries. To that purpose, the understanding of mechanisms at different scales is crucial. This paper shows how the implementation of characterisation techniques at sub-micrometric scales allows to understand these mechanisms. The techniques evocated here are: electronic microscopy (FESEM, TEM), X-ray absorption spectrometry under synchrotron radiation (STXM) and mass spectrometry (nanoSIMS) applied after isotopic labelling.

Two tests of iron corrosion in compacted clay and clay slurry were performed for several years. T... more Two tests of iron corrosion in compacted clay and clay slurry were performed for several years. The corrosion systems, and especially the interfacial layer between the metal and the corrosion products, were investigated post mortem by SEM-FEG, mRaman, MET and STXM. An Fe(III) oxide layer systematically developed at a nanometer scale between the metal and an outer layer of carbonates. Its presence could explain the slowing down of the corrosion rate usually observed for these systems. Depending of the compactness of the environment the nature of the interfacial layer is not the same.

Large quantities of iron reinforcements, found in most Gothic monuments, are a data source for th... more Large quantities of iron reinforcements, found in most Gothic monuments, are a data source for the interpretation of medieval architecture however their role both in contemporary engineering theory and the technical reality of construction yards has not yet been specified due to the difficulty of directly dating them. We present here an original radiocarbon dating methodology to date metal itself. Radio-carbon dates were measured for iron reinforcements used in specific parts of Bourges and Beauvais cathedrals, two iconic buildings in the development of French gothic architecture. Coupled with archaeometric and archaeological data, the new chronological results illuminate the major and active roles played by iron in the strategy of the building yards. At Bourges, iron was assimilated into the ca-thedral's construction strategy, whereas at Beauvais iron was integrated from the initial design, added to the monument following the vicissitudes of the building yard, and still used during the modern period. Thus, through decisive advances in radiocarbon dating of iron artefacts, the evolution of medieval architectural and engineering thought and action has been more reliably reconstructed.

Architecture represents key evidence of dynastic practice and change in the archaeological world.... more Architecture represents key evidence of dynastic practice and change in the archaeological world. Chronologies for many important buildings and sequences, including the iconic temples of medieval Angkor in Cambodia, are based solely on indirect associations from inscriptions and architectural styles. The Baphuon temple, one of the last major buildings in Angkor without textual or scientifically-derived chronological evidence, is crucial both for the context and date of its construction and the period when its western façade was modified into a unique, gigantic Reclining Buddha. Its construction was part of a major dynastic change and florescence of the Hindu-Mahayana Buddhist state and the modification is the key evidence of Theravada Buddhist power after Angkor's decline in the 15 th century. Using a newly-developed approach based on AMS radiocarbon dating to directly date four iron crampons integrated into the structure we present the first direct evidence for the history of the Baphuon. Comprehensive study of ferrous elements shows that both construction and modification were critically earlier than expected. The Baphuon can now be considered as the major temple associated with the imperial reformations and territorial consolidation of Suryavarman I (1010–1050 AD) for whom no previous building to legitimize his reign could be identified. The Theravada Buddhist modification is a hundred years prior to the conventional 16 th century estimation and is not associated with renewed use of Angkor. Instead it relates to the enigmatic Ayutthayan occupation of Angkor in the 1430s and 40s during a major period of climatic instability. Accurately dating iron with relatively low carbon content is a decisive step to test long-standing assumptions about architectural histories and political processes for states that incorporated iron into buildings (e.g., Ancient Greece, medieval India). Furthermore, this new approach has the potential to revise chronologies related to iron consumption practices since the origins of ferrous metallurgy three millennia ago.

This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/authorsrights a b s t r a c t A specific statistical approach was tested to determine the ironmaking processes (bloomery or indirect) used to manufacture iron reinforcements found in two French gothic medieval monuments: Metz and Beauvais Cathedrals. Slag inclusions embedded in the metallic matrix were analysed and the major element compositions were quantified, using a Si Drift EDS detector permitting the study of several hundred inclusions per artefact. First, pre-processing was applied to the raw data to discriminate inclusions from the smelting stage (or refining stage for the indirect process) from those formed during post-reduction operations (forging etc.). PCA and hierarchical clustering on the major element compositions were then performed. Secondly, a specific multivariate statistical method, logistic regression, was applied to a learning set of data from a reference set of samples. This allowed the development of a model capable of distinguishing artefacts from the two smelting processes and to link unknown samples to one or the other. This model was then used to study artefacts from the Mutte Tower of Metz Cathedral and Beauvais Cathedral. This allowed us to confirm the extensive use of iron reinforcements since the construction of Beauvais cathedral. In the Mutte Tower of Metz Cathedral clamps from Lorraine reinforced some parts of the monument from its construction between the 13th and the 15th centuries.

This paper develops new reflections regarding the provenance of iron artefacts, by defining the t... more This paper develops new reflections regarding the provenance of iron artefacts, by defining the trade networks that might have supplied the building yard of the Metz city belfry at the end of the 15th century. Regional field surveys were carried out in Lorraine in order to constitute a chemical repository, including ironmaking zones considered as the most probable metal providers. The chemical characterization—both major and trace elements—of slag inclusions entrapped in the metallic matrix of iron reinforcements was performed in order to compare their chemical signature to the reference set. A statistical approach based on the combined use of descriptive multivariate analyses was developed to infer the origin of the metal supplied to the building yard. As the multiplicity of potential metal providers was assessed from former studies, the results obtained underline the place taken by local workshops in the supply strategy developed by the builders. This study thus provides crucial information supporting a discussion about the scale and the organization of such networks at the end of the Middle Ages.

Iron sulphides are observed on long term anoxic corrosion profiles of iron artefacts. The archaeo... more Iron sulphides are observed on long term anoxic corrosion profiles of iron artefacts. The archaeological nails studied came from two terrestrial sites (Glinet and Raadhuspladsen) and a subaquatic one (Arles-Rhône 3). Greigite (Fe 3 S 4) and/or mackinawite (FeS 1−x) are observed at the outer border of the corrosion product layer. The presence of mackinawite is discussed relatively to the establishment of stable anoxic burial conditions. The nails from the subaquatic site present pyrite globules in the transformed medium. The formation of pyrite (FeS 2) is attributed to the proximity of wood. The iron sulphides formation may also be explained by the presence of sulphate-reducing bacteria in the burial environment.

Glass long term alteration in the context of high-level radioactive waste (HLW) storage is influe... more Glass long term alteration in the context of high-level radioactive waste (HLW) storage is influenced by near-field materials and environmental context. As previous studies have shown, the extent of glass alteration is strongly related to the presence of iron in the system, mainly provided by the steel overpack around surrounding the HLW glass package. A key to understanding what will happen to the glass-borne elements in the geological disposal lies in the relationship between the iron-bearing phases and the glass alteration products formed. In this study, we focus on the influence of the formation conditions (synthetized or in-situ) and the age of different iron corrosion products on SON68 glass alteration. Corrosion products obtained from archaeological iron artifacts are considered here to be true analogues of the corrosion products in a waste disposal system due to the similarities in formation conditions and physical properties. These representative corrosion products (RCP) are used in the experiment along with synthetized iron anoxic corrosion products and pristine metallic iron. The model-cracks of SON68 glass were altered in cell reactors, with one of the different iron-sources inserted in the crack each time. The study was successful in reproducing most of the processes observed in the long term archaeological system. Between the different systems, alteration variations were noted both in nature and intensity, confirming the influence of the iron-source on glass alteration. Results seem to point to a lesser effect of long term iron corrosion products (RCP) on the glass alteration than that of the more recent products (SCP), both in terms of general glass alteration and of iron transport.

In the context of conservation of ferrous cultural heritage, dechlorination processes of archaeol... more In the context of conservation of ferrous cultural heritage, dechlorination processes of archaeological iron artefacts are studied in subcritical conditions which consist of immerging an artefact inside an alkaline bath under pressure (30 bar) and temperature (160 8C). Submarine archaeological environments lead to the presence of chlorides inside the corrosion layers. After exposure to the atmosphere following excavation, initial corrosion phases evolve. Chlorides remain trapped inside the structure of corrosion products particularly during the crystallisation of akaganeite. Stabilisation treatment objectives are to remove chlorides from the corrosion layers and to obtain more stable phases. A Roman archaeological bar has been studied on cross-section before and after treatment in sub-critical conditions. Less stable phases, such as ferrihydrite and akaganeite, transformed into hematite. That was confirmed by the use of synthetic and pure phases treated in the same conditions. The presence of goethite before and after the treatment in the corrosion profile raises the question of its reactivity during dechlorination process. Akaganeite has been synthesised and compared to archaeological powder sampled on an artefact. The results highlight reactivity differences indicating that sub-critical transformation processes are not only dependent on the nature of phases but also on intrinsic physical characteristics.

Le regard porté sur les sociétés du passé et leurs systèmes techno-économiques permet une mise en... more Le regard porté sur les sociétés du passé et leurs systèmes techno-économiques permet une mise en perspective sur le temps long de problématiques éminemment actuelles. Cet ouvrage rassemble sept contributions illustrant le dialogue à l’œuvre entre les sciences archéologiques et ces problématiques, en lien avec l’innovation: intolérance au lactose et histoire de l’exploitation laitière, maîtrise des cycles de reproduction en élevage, amendement des sols et développement durable en agriculture, prévision du comportement de matériaux dans les siècles futurs, nano-structuration et synthèse de nano-particules, imagerie tridimensionnelle en paléoanthropologie appliquée à la chirurgie reconstructrice. Ces exemples montrent comment les recherches sur les sociétés du passé, si elles ont leur intérêt propre, permettent également de ranimer les grandes problématiques de nos sociétés contemporaines, et peuvent parfois même être source d’innovation technique.

La problématique de la détermination de provenance des matériaux et des objets archéologiques est... more La problématique de la détermination de provenance des matériaux et des objets archéologiques est un des questionnements clés en archéologie pour restituer les réseaux d’échanges, les niveaux techniques, les contacts culturels, économiques et sociaux au sein des sociétés anciennes. L’analyse physico-chimique des matériaux anciens est un outil puissant pour répondre à ces questions. Elle a vu, ces dernières années, d’importants progrès méthodologiques, en particulier pour des matériaux dont il était difficile jusqu’alors de déterminer les origines. Par ailleurs, les approches méthodologiques, pour qu’elles soient efficaces, doivent être adaptées et peuvent être très complexes. Elles se doivent également d’être menées en symbiose avec les approches archéologiques et historiques.

Le présent ouvrage a pour objectif de faire un bilan sur l’ensemble de ces points, et ceci à destination des différentes communautés concernées : archéologues, conservateurs, historiens et archéomètres… Il offre un large panorama et les bases nécessaires pour aborder les problématiques « provenance » à la lumière des dernières avancées dans le domaine. Il se divise en 2 parties. La première traite, pour chacun des matériaux considérés, des problématiques archéologiques et archéométriques liées aux études de provenance. La seconde vise à exposer, de manière pratique et accessible, quelques techniques analytiques majeures pour les études de provenance et de circulation.

This book aims to give state of the art in several domains of cultural heritage in which Nanosc... more This book aims to give state of the art in several domains of cultural heritage in which Nanosciences allow fundamental breakthrough. The first part of the book concerns nanostructured materials in ancient artifacts. Understanding their nature and formation processes bring new insight in the apprehension of technical level of ancient societies but can also inspire the design of new materials. The second part is dedicated to the understanding of materials. This crucial issue in material science today, for cultural heritage, needs to perform specific characterization techniques and technologies, but also to create tailored analytical strategies. Part three presents new methods, processes and materials at nano levels that can bring innovative solutions to conservation and restoration issues, linked with the understanding of the alteration processes involved at different scales.