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When attempting to sufficiently protect outdoor bronze monuments from corrosion, searches for an effective solution are usually based on coating applications which have a high anticorrosive efficiency. In order to correctly assess the level of protection provided by such coatings, adherence (practical adhesion) measurements need to be performed for the proper evaluation of the deterioration of coating systems with aging. Although a coupled study of adherence with aging would be of great interest, very few such studies are available. In this work, a methodological approach is proposed for the evaluation of coatings applied to metallic cultural heritage monuments of, based on the use of a three-point bending test. Adherence characterization of different protective coatings has been performed both on bare and on traditionally black-patinated bronze coupons (Cu–Sn alloy with 5.9 wt% Sn), which were used as basic model substrates. The investigated coatings were Incralac®, silane, sol–gel oxysilane, and a silane-modified polymethacrylate (an adhesion promoter for fluoropolymer). The results of measurements which were obtained before and after accelerated aging in concentrated acid rain made it possible to more easily differentiate between the various adherence levels of different coating systems. Coupled with adherence measurements, the results of systematic optical and SEM observation of the different failure morphologies are also presented. In the case of the coated bare alloy, adhesive failures were mainly observed. The silane (PropS-SH) coating showed the best adherence. In the case of the patinated bronze test specimens, only cohesive failures occurred. Adherence is directly related to the cohesion of the black patina rather than that of the applied coating. It was observed that aging reduces the level of the adherence. [ABSTRACT FROM AUTHOR]

Abstract From the moment of purchase, pristine objects are subjected to an array of stimuli including wear, impact, heat, light, water and air which alter their tactile and aesthetic properties. Material change is often regarded as 'damage' or 'degradation' and contributes to premature obsolescence but has potential to be used as a tool to engender emotional engagement with an object and extend product lifetimes. However, materials resources for designers rarely provide information about how materials will change in use. In this paper we draw on a combination of literature and user studies to elucidate the complex web of factors which contribute to changes in material surfaces, which we present in a 'framework for understanding material change'. We go on to explore the role that changes to product material surfaces, and the design of objects to change in particular ways with use, could have on the transition to circular modes of consumption. A range of resources which aim to increase designers' understanding of material change are presented, and the challenges of creating, utilising and developing these resources are discussed. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

This article examines how notions of patina are conveyed by experts in the antiques trade. How do antiques experts convey perceptions of patina to their clients and audience? How do they explain, persuade, and put forward their standards of condition? Three examples are analysed, a conversation about a sundial from the Swedish Antiques Roadshow, a conversation about a toy car from the British Antiques Roadshow and a vintage watches collecting guide from Christie's auction house. Different persuasive strategies and styles used by the experts to convey their norms are identified. A change towards higher appreciation of patina can be discerned. Furthermore, the article analyses patina in regard to the relationship between surface and core of an object and in regard to use and usefulness. It is suggested that objects with patina are popular because we as humans feel an affinity with them. If things have a life trajectory, it will also involve ageing, and by surrounding ourselves with old, imperfect things we can come to terms with our own ageing process. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Long-term atmospheric corrosion and metal release studies of Sn-bronze and Cu metal at urban and marine environments. • The presence of Sn oxides in the native Cu 2 O rich surface oxide of Sn-bronze improves its barrier properties. • Sn alloying reduces the corrosion rate of Sn bronze at urban conditions. • No beneficial corrosion effects of Sn alloying at chloride-rich marine conditions. • Metal release marginally influenced by Sn alloying. Abstract The role of Sn on the atmospheric corrosion performance of binary Cu-Sn bronze alloys (4–6 wt.% Sn) compared with Cu metal used in outdoor architecture is elucidated in terms of microstructure, native surface oxide composition, patina evolution, corrosion rates, appearance and metal release. Results are presented for non-exposed surfaces and surfaces exposed at different urban and marine sites in Europe up to 5 years and based on multi-analytical findings from microscopic, spectroscopic, electrochemical and chemical investigations. Alloying influenced the corrosion, aesthetic appearance and patina evolution, differently for urban and marine sites, whereas no effects were observed on the release pattern. [ABSTRACT FROM AUTHOR]

In our paper, we report a workflow, which combines cleaning procedures and Gas Chromatography Mass Spectrometry (GC-MS) for the removal and the identification of a patina from a byzantine 15th century icon representing the Virgin and Child. Our strategy suggest a convenient interaction between restoration procedures and analytical methodologies aimed at the cleaning of the surface of the artwork and the identification of unknown compounds responsible for its alteration. These informations can be very useful not only to return the colors to their original brightness but to reconstruct the story of the icon too. [ABSTRACT FROM AUTHOR]

The paper reports the results of the analyses performed on a Roman quadrans dating back to the first century ad, belonging to a group of more than 8.000 coins found in the bed of river Tiber during an archaeological research in 1987–1988. The quadrans was examined by means of X‐ray diffraction, scanning electron microscopy, energy dispersion spectroscopy, and X‐ray photoelectron spectroscopy. Energy dispersion spectroscopy analytical results confirmed that the coin is made of pure copper. The compounds present in the patina have been identified through X‐ray diffraction. The spectrum is the overlapping of several peaks, and the results show that the patina substantially consists of malachite Cu2CO3(OH)2, cupric chloride CuCl2, and nantokite CuCl. X‐ray photoelectron spectroscopy only evidences nantokite because of the different analysis depths of the two techniques. This means that nantokite forms a thin outer layer in the concretion covering the quadrans. [ABSTRACT FROM AUTHOR]

The antimicrobial function of Cu surfaces can be linked to soluble Cu release from corrosion. However, direct replacement of high-touch surfaces with Cu-based alloys is limited by knowledge gaps regarding how alloying directly relates to corrosion. A systematic approach to determine the role of Sn as a solute element and the minimum alloy content for passivation has been lacking. High-purity arc-melted binary alloys of Cu-Sn with specific additions of 0.1, 1, 5, and 10 wt% Sn were compared to pure Cu and Sn. The role and amount of Sn in corrosion products (patina) formed on the alloy surface as a function of alloying was interrogated in artificial perspiration. The fate and identity of the solute (Sn) and solvent (Cu) elements following corrosion, as soluble ions or insoluble corrosion products, was investigated. Alloy patinas became increasingly enriched in Sn corrosion products identified as SnO 2 with increasing Sn content in the alloy. The critical alloy content for complete SnO 2 layer coverage were theoretically quantified through a model based on interfacial surface energy. The predicted minimum solute content for a complete conformal inner layer of SnO 2 was 1 wt% Sn whereas experimentally complete coverage was achieved only at 10 wt% Sn. Differences between theory and experiment are discussed. [ABSTRACT FROM AUTHOR]

Supercritical carbon dioxide (scCO 2 ) treatment was employed for rapid formation of a zinc patina layer on hot dip galvanized (HDG) steel. In the presence of H 2 O and a Cu precursor, an artificial patina consisting of two distinctive phases was formed: a dense ~ 1 μm layer of anhydrous ZnCO 3 adjacent to native zinc coating, and a needle-like porous structure showing resemblance to hydrozincite (Zn 5 (CO 3 ) 2 (OH) 6 ). The artificial patina layer significantly decreased the surface free energy of HDG, which was evidenced also by good wettability by a polyester melamine coating. Furthermore, the needle-like patina surface structure stayed intact through the coating process, indicating improved coating adhesion. ScCO 2 treatment facilitates rapid and impurity-free surface treatment of hot dip galvanized steel, and could be used to tailor novel adhesion and corrosion promoting surface morphologies. [ABSTRACT FROM AUTHOR]

This paper presents an in-depth characterisation study of the patina formed on a copper tile taken from the roof of Queen Anne's Summer Palace in Prague after > 300 years of exposure to the action of the atmosphere. A wide variety of techniques have been used, including metallographic and chemical analysis (electrogravimetry, AAS, XRF) of the copper matrix, and spectroscopic and microscopic investigations (GIXRD, FTIR, TEM/EDS and SEM/EDS) to determine the composition and structure of the patina. The major conclusions of the study are: (a) the base copper contains abundant inclusions mainly of rosiaite (PbSb 2 O 6 ); (b) the patina is formed by an inner sublayer of cuprite (Cu 2 O) and an outer sublayer of brochantite [Cu 4 SO 4 (OH) 6 ] and antlerite [Cu 3 SO 4 (OH) 4 ] and traces of azurite [Cu 3 (CO 3 ) 2 (OH) 2 ]; and (c) the brochantite/antlerite crystals are randomly doped with Fe and C. [ABSTRACT FROM AUTHOR]

Copyright of Stratum Plus Journal is the property of P.P. Stratum plus and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article discusses the conservation issues of Roman coins on the example of a specific find, gives an overview of the conservation process and material studies. It analyses corrosion products and the historic patina survived on the coin surface. The author endeavors to establish connections between the composition of the coin metal and corrosion. [ABSTRACT FROM AUTHOR]

Bronze has been positioned as the medium par excellence for sculptural production bearing the aesthetic, symbolic and poetic values that have propitiated the construction of a metallurgical archetype, which has its genesis in its physicochemical, metallurgical and mechanical properties. Of these properties, the formation of the patina is the one that contributes most to the construction of its poetic image, since it is the one that, along with the form, suddenly appears before the spectators, directly affecting their perception of the work. To exemplify this, we analyze the patina of the sculpture La Piedad by Bernardo Vieco using SEM-EDX and XRD. The results show a non-protective patina that, added to the other factors of deterioration of the work, contribute to the drama of the scene that is represented, taking it from pain and impotence before the death of a loved one, to a state of hopelessness and apathy embodied in a bronze that deteriorates over time with environmental factors and neglect in the protection and conservation of the work. [ABSTRACT FROM AUTHOR]

This article presents the development of corrosion products and results of experimental atmospheric corrosion test on bearing structures of weathering steel railway bridge in Prague-Motol. This bridge structure is a part of long-term research project focused on development of corrosion processes at different structural elements of supporting structures. Measurements of corrosion losses and average thicknesses of corrosion products are carried out on selected surfaces of weathering steel structures. The article presents results of corrosion tests after one and three years of exposure of corrosion specimens. The results indicate a high degree of correlation dependence between measured average thickness of corrosion products and corrosion losses. [ABSTRACT FROM AUTHOR]

What is ‘age value’? Or conceptualised slightly differently, what is the fundamental difference in the experience and affect of old and new places? In order to answer this question, this study compares historic Charleston, an authentically ‘old’ place and I’On, a ‘new’ place designed on new urbanist principles; both places share essentially the same design but differ in age by over 150 years. A sequential mixed-method approach, consisting of a phenomenology (interviews) followed by a measure of four dimensions of place attachment provided the data for this study; both methods employed photo elicitation techniques. Age value is only associated with patina and spontaneous fantasy in historic Charleston; both of these variables correlate with increased levels of general attachment or dependence. Residents of both neighbourhoods exhibit very high levels of general attachment, dependence and identity, but rootedness is higher in Charleston. Place attachment is correlated with more environmental variables in historic Charleston than it is in I’On. It is important to protect masonry patina because of its association with place attachment. This study lends evidence for why we need to understand the values, perceptions and experiences of civil experts in balance with the objective art/historical values of conventional experts.ABSTRACT FROM PUBLISHERCopyright of International Journal of Heritage Studies is the property of Routledge and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. [ABSTRACT FROM AUTHOR]

The presence or absence of use-wear marks on copper (Cu)-alloy weaponry has been used since the late 1990s to investigate the balance between functional (combat) and symbolic (value, status, religious) use of these objects, and thus explore their social and economic context. In this paper, we suggest that this work has not taken sufficient account of the material properties of Cu-alloys. We discuss mechanisms of plastic deformation, incremental repairs and corrosion in detail to show how these can obscure use-wear traces. In a survey of Cu-alloy weaponry from the Nordic Bronze Age (1800/1700–550 BCE) from Denmark, Sweden and Germany, we show that corrosion of Cu-alloy objects is strongly linked to depositional context, being greater in burials (both inhumations and cremations) than hoards or as single objects. A relative paucity of use-wear marks on burial weapons should therefore not be used to argue that these were purely symbolic objects, e.g. in contrast to the better preserved hoard material. We propose that use-wear traces on Cu-alloy weaponry, particularly on blade edges, is significantly more elusive than previously realised, and that undamaged objects have been over-identified. [ABSTRACT FROM AUTHOR]

The morphology and elemental composition of cross sections of eight historic copper materials have been explored. The materials were taken from copper roofs installed in different middle and northern European environments from the 16th to the 19th century. All copper substrates contain inclusions of varying size, number and composition, reflecting different copper ores and production methods. The largest inclusions have a size of up to 40 μm, with most inclusions in the size ranging between 2 and 10 μm. The most common element in the inclusions is O, followed by Pb, Sb and As. Minor elements include Ni, Sn and Fe. All historic patinas exhibit quite fragmentized bilayer structures, with a thin inner layer of cuprite (Cu2O) and a thicker outer one consisting mainly of brochantite (Cu4SO4(OH)6). The extent of patina fragmentation seems to depend on the size of the inclusions, rather than on their number and elemental composition. The larger inclusions are electrochemically nobler than the surrounding copper matrix. This creates micro-galvanic effects resulting both in a profound influence on the homogeneity and morphology of historic copper patinas and in a significantly increased ratio of the thicknesses of the brochantite and cuprite layers. The results suggest that copper patinas formed during different centuries exhibit variations in uniformity and corrosion protection ability. [ABSTRACT FROM AUTHOR]

When unearthed from soil, many plated bronzes were covered with a thick layer of patina that hid their original shiny lustre. A sandwich structure is observed in their cross-section including superficial patina, plated layer and inner patina. In this paper, a hydrogel cleaner, composed of polyvinyl alcohol (PVA) and Carbomer, and added by formic acid and cysteine, is introduced as de-rusting agent which can not only remove the patina from the surface of plated bronzes successfully, but also keep their original lustre. [ABSTRACT FROM AUTHOR]

Статья посвящена описанию коллекции Музея колокольного звона в Новосибирске, а именно колоколов, составляющих музейную экспозицию «Церковные колокола Сибири». По каждому колоколу приведены историческая справка, особенности изготовления и сохранности внешнего вида, декоративный орнамент и наличие надписей. Большая часть описываемых колоколов поступили в музей в 2011-2012 годах. Колокола условно разделены на несколько групп, с целью разработки экспозиционного плана на современном этапе

This paper presents the results of scientific examinations and analyses carried out on the archaeological coins discovered in Najran, Saudi Arabia. Optical microscopy (OM), scanning electron microscopy (SEM) coupled with energy dispersive spectrometry (EDS) and X-ray diffraction (XRD) were used to investigate morphological corrosion features, to clear the nature of the patina and to analyze the elementary composition. Morphologically, it was revealed that there are reniform, coral reef and dendritic shapes of corrosion products and heterogeneous multicolor patina on the studied coin surfaces. It was proven that those coins were made of a silver-copper alloy and were covered by three superficial corrosion layers. The main composition of the coin corrosion compounds was identified as copper carbonate, copper chloride, copper silicates, silver chlorides and silver sulphide. The proposed corrosion mechanism revealed that those coins were characterized by heavy degradation phenomena, induced by corrosive species and soil contaminants. The corrosion processes led to the depletion of the copper and silver enrichment near the surface, as compared to the core composition. This study provides useful information for the conservation and preservation of the Najran hoard coins.

This paper presents the results of scientific examinations carried out on an Egyptian bronze statue discovered buried in Sais. Optical Microscopy (OM), Scanning Electron Microscopy (SEM) coupled with Energy Dispersive Spectroscopy (EDS) and X-ray Diffraction (XRD) were used to understand the corrosive morphological characteristics of the patina, to investigate the corrosion products, analyze the elementary composition of the statue and to identify the corrosive factors with effects on the alteration processes. The results indicated that the statue was made of bronze alloy, with copper as the main element, besides lead and tin. Three layers of alteration products with various composition and morphology covered the substrate of the bronze alloy. XRD results indicated that the statue was subjected to many corrosive ions such as sulfur and chloride, and buried in wet soil, rich in oxygen and carbon. This study provides useful information for the restoration and protection of the statue.

In recent years, due to increased air pollution, bronze objects exposed in urban areas suffer continuous degradation. Therefore, it is important to find efficient methods to protect them against corrosion. The present work aims to investigate the corrosion resistance of various artificial patina currently used in bronze sculpture. Once formed, the patina is relative stable and acts as a protective coating of the bronze object under many exposure conditions. The protective effect of different artificial patinas was comparatively investigated by electrochemical and non-electrochemical methods.

The patterns of colour on stone buildings change with time. Buildings were blackened by coal soot, but now mostly diesel particles and in future, wind-driven rain may alter the patterns and oxidation of surface organics. Colouring patterns that outline or shadow architectural elements are publicly more acceptable than those that cut across them e.g. rain streaking. Thresholds of acceptability for blackening can be related to soot loading. When soot loading of the ambient air is high, e.g. near busy roads, buildings are dark and typically viewed as unacceptable. However at lower concentrations (2-3 μg m-3 elemental carbon), building appearance is typically seen as more acceptable. The future offers a potential for variation in building colour, arising through different biological growth under changing climates or the presence of different pollutants. In future urban atmospheres more dominated by organic pollutants a yellowing process may be more important. Diesel soot has many organic compounds that can oxidise to brownish-coloured humic-like (HULIS) materials. We illustrate the development of colour patterns on the Cathedral Church of St John the Baptist, Norwich UK from its opening (beginning of the 20th century) to the end of the 21st century derived from historic photographs, observations and predictions for the future appearance. The latter has to consider removal of deposits by changed rainwater flow and enhanced biological activity. Blackening from coal smoke may have reached a peak around 1960s and 1970s, but diesel soot predominates now.

In the archaeological Khmer complex (Cambodia), an unusual black patina covering both the exterior and interior walls of the Neang Khmau temple, has been observed during a recent conservative survey. In fact, it is present over all the four facades of the temple, covers a relevant part of the vertical surfaces protected from rainfall and is also homogeneously distributed on the interior of the monument. The upper and the lower areas show, on the contrary, a relevant lichen growth. The temple was built by using laterite bricks, a natural material common in tropical areas as a weathering product of pre-existing rocks. A preliminary investigation on the patina samples together with ecological considerations excluded a biological origin of the black alteration, thus prompting a more detailed study. In this work, we have investigated the physico-chemical origin of this unusual patina by identifying its mineralogical and chemical composition. Raman and FTIR spectroscopies, SEM-EDS, micro-XRF and XRPD have been applied to characterize the alteration products. Analyses have been performed both on single fragments and on polished cross sections collected from all four temple facades and from one area in the temple interior. Optical observations of the cross sections have evidenced irregularities in the thickness of the patina. Raman and FTIR spectra have revealed that the black layers are mainly composed of manganese minerals (hollandite, romanechite and manganite). This peculiar alteration pattern is interpreted as because of the tropical climatic conditions of Cambodia. Indeed the variation of wet and dry seasons favours the migration of iron and manganese ions and their successive immobilization in regions not directly subject to leaching. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

We report results of the patina study of underwater archeological finding of medieval copper objects performed by means of the Raman and complementary spectroscopic techniques. The objects were found submerged in the sea as cargo part of the ship which sunk in the Gulf of Gdańsk in 1408. The excavated collection consists of 230 oval ingots of the size and mass up to about 60 cm and 18 kg (total of 2 tons), respectively. In the Raman spectra of the strongly porous ingot encrustation, the bands corresponding to the main patina representatives such as cuprite (Cu2O), atacamite (Cu2(OH)3Cl) and chalcopyrite (CuFeS2), and also chalcocite (Cu2S) and covellite (CuS) are observed and confirmed by the elemental analysis. Raman bands located at 1473 cm−1 and also at 909 and 511 cm−1 are ascribed to the organic Ca-oxalate (whewellite, CaC2O4 · H2O) in agreement with the infrared spectra and surface morphology observed in microscope images. The presence of S, C, Ca, and Fe revealed by the energy dispersive X-ray spectroscopy indicate on patina components resulting from reactions in the microbial environment in seawater and on contributions coming from iron bars, tar, and burnt remains which were also found in the excavated cargo. The results are consistent with literature data on copper ingots from Hungary traded along the south-north route in medieval Europe. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this study, atmospheric corrosion of copper exposed for 4 years in 12 different cities of Iran with various climatic characteristics was determined by weight loss method. Also, the corrosivity index of each city was classified using environmental factors according to the ISO 9223 standard. The results indicated good agreement between two approaches recommended by ISO standards. Accordingly, the corrosion rate of copper in Iran can be predicted according to the empirical kinetic equation (). Morphology, chemical composition and crystalline phases of patinas in cities with different kinetic behaviours were compared via SEM, EDS and XRD, respectively. [ABSTRACT FROM AUTHOR]

Transportable energy dispersive X-ray fluorescence (XRF) spectrometers allow the elemental composition of coins to be measured at collections, enhancing security while maximizing access to historically important material. We assessed 10 silver coins, using five XRF spectrometers. We found no systematic differences between analyses using Mo- and Rh-anode tubes, and no substantial advantage using He flush over air for elements heavier than Ti. Higher voltage X-ray tubes enhanced analytical precision. Understanding patina composition made a numerical correction possible, allowing an approximation of the underlying coin metal with good results for metals including Cu, Ag, Au, Pb, and Bi. [ABSTRACT FROM AUTHOR]

Alabaster is a white and pure gypsum rock classically used in sculptures or for ornamental purposes, but its characteristic white colour is sometimes masked by the development of noticeable reddish stains over the surface of the rock. The main altarpiece of the Santa Maria de Poblet monastery (Tarragona, NE Spain; 16th century, Damià Forment) is the focus of this study. Red-to-ochre patinas with diameters of 2–20 cm are found on the alabaster surface of this altarpiece. The origin of such patinas are discussed, as they are the result of degradation processes of minerals present in alabaster rocks, contrary to what happens in the formation of most patinas. The patinas consist of two differentiated layers that may occur occasionally mixed. The Lower Layer contains iron compounds, which have precipitated around the gypsum crystals of the rocky support and have provided the characteristic red-to-ochre colour to the surface of the altarpiece. The formation of this layer was driven by the (bio)oxidation of the pyrite, which is disseminated over the alabaster surface. The formation of this film of iron-rich particles was conducted by a series of destructive and penetrative processes, promoting disaggregation and crystal reduction (mechanical and/or by dissolution) of the matrix minerals (gypsum, celestite, barite, calcite-dolomite…). The Upper Layer was grown by means of constructive (agglutination of particles by accretion) and destructive (destruction of the alabaster matrix and incorporation into the Lower Layer) mixed processes. Thus, the presence of small crystals (1–10 μm) of gypsum, quartz, calcite, celestite, barite, clay minerals and pyrite in this upper patina are mainly related to the residual products of the alabaster rocks. Moreover, some of the calcite, quartz and clay particles could also be considered atmospheric dust. Oxalates (weddellite and whewellite), portlandite and coal particles are not related to the formation of iron-rich patinas. Such studied patinas might date from the 19th century due to the partial destruction of the monastery after the approval of the Law of Confiscation of Religious Properties in Spain (1835) and no later than the end of the ninetieth century, when the monastery was abandoned. The entry of rainwater and presence of humidity inside the monastery would promote the pyrite oxidation processes. Currently the patinas seem to be stabilized, the pyrites are no longer in contact with water, which is needed for oxidation. [ABSTRACT FROM AUTHOR]

Program of experimental atmospheric corrosion tests carried out on weathering steel bridges in the Czech Republic is briefly introduced in this paper. Attention is paid to the evaluation of corrosion processes on load-bearing structures of girder bridges with the roadway above the supports. The article presents selected results of experimental atmospheric corrosion testing aimed at the measurement of corrosion products thicknesses. It results from the tests that corrosion processes on weathering steels bridges are significantly conditioned by position and location of exposed surface within the structure. [ABSTRACT FROM AUTHOR]

Building materials from the Monastery of Uclés façades, in Cuenca (16th-18 th centuries), have been characterised, as well as identified their deterioration forms. Characterization consisted of the determination o mineralogical and petrographical properties of building materials; petrophysical and petrochemical characterization of building stones were also carried out. Stony materials are basically of two types, dolostones and limestones. Ashlars joint mortars are of three classes, chronologically from the oldest to the newest: lime mortars with siliceous and dolomitic aggregates, gypsum/lime mortars with dolomitic aggregates, and gypsum/lime mortars with siliceous aggregates. The façades have been protected with artificial patinas of three kinds: lime, lime/gypsum and gypsum patinas, chronologically from the oldest to the newest, with a variable thickness from 500 µm. The dolomitic fades are better conserved than the calcareous ones, and the covering artificial patinas presence have preserved the materials on which they were applied.

In this article we expose the technics used to characterize the materials of the ceiling that covers the Mayor sacristy of Seville's Cathedral and the causes of the loosening of mortar and stone fragments, we also expose some ways to overcome this fact.

In November 1998 an international team, sponsored by the National Geographic Society and the Fund for Scientific Research-Flanders (Belgium), conducted a rock art survey in the vicinity of El-Hosh in Upper Egypt. A multitude of sites with thousands of petroglyphs was located. Attention was paid mainly to the oldest manifestations of rock art in the area representing intensively patinated, mushroom-shaped, curvilinear and geometric designs, as well as a number of seemingly associated anthropomorphic figures, footprints, and zoomorphs. Several of these drawings were sampled for possible AMS 14C dating. A number of complex rock art panels were recorded in their entirety. In addition, the distribution of the sites has been studied in relationship to the geomorphological particularities of the area.

Portoro is one of the most famous Italian black limestones due to its characteristic golden-yellow veins on a black background. It was used since Roman times, mainly in the city of Luni. Since the Middle Ages, its use is widespread in Genoa, and from the XVII century, it became one of the most common stones in religious buildings throughout Italy. At the end of the XIX century, its use has spread abroad, particularly in Europe and USA. It was extracted in several quarrying areas located near La Spezia, but at present, only five quarries are active. This stone, exposed to weathering, tends to bleach losing the appearance of its golden streaks that determine its aesthetic appeal. This research deals with the petrographic and chemical characterization of the Portoro macchia larga variety as well as the study of its chromatic alteration in order to define guidelines for the most suitable use of this stone and for restoration works. [ABSTRACT FROM AUTHOR]

The previously developed voltammetric method using a strongly alkaline electrolyte (6 M KOH + 1 M LiOH) as the supporting electrolyte was applied for simultaneous determination of copper corrosion products, including oxides and patinas. The reduction peaks of these chemical species could be separated in the electrolyte. When the method was applied to samples with patina, the fast exchange reaction presumably occurred between SO42- or CO32- ions in patinas and OH- ions in the electrolyte, so that the reduction peak of the patina could be observed at potentials close to that of Cu(OH)2. [ABSTRACT FROM AUTHOR]

This paper deals with experimental corrosion tests carried out on weathering steel bridges. The basic property of the weathering steel is its ability to create a protective layer on its surface in favorable environments. This protective layer called patina covers the surface of the whole structure, protects against external climatic influences and the construction resists completely without an anticorrosion coating. This paper presents the program of experimental atmospheric corrosion test carried out on road bridges made of weathering structural steel. The article presents results of corrosion tests after one year of exposure of corrosion specimens. This paper describes the influence of the position and location of an exposed surface, evaluates the different development on typical surfaces affected by leaking water and explains the high degree of correlation dependence between measured corrosion loss and average thickness of corrosion products. [ABSTRACT FROM AUTHOR]