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Copyright of Materials & Technologies / Materiali in Tehnologije is the property of Institute of Metals & Technology 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.)

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]

Artistic patination is a traditional colouring technique for metal sculpture, employed by artists in ancient and modern times for aesthetic purposes. Today, knowledge of the artistic value and the chemistry of this superficial chromatic layer, called 'artistic patina', can be successfully acquired through a close collaboration between living artists, foundry artisans, and scientists. Starting from several interviews with the Italian artist Nado Canuti and foundry artisans, specific information was gathered about patination methods and the artist's attitude towards materials restoration. Afterwards, the patinas most used by Canuti were reproduced to study their nature before any ageing or degradation. Their chromatic values, morphologies, and compositions were studied employing a range of techniques such as colour measurements, scanning electron microscopy with energy dispersive X-ray spectroscopy, and micro-Raman spectroscopy. The collected data revealed the formation of main compounds (cuprite, cassiterite, rouaite, chalcocite, isocubanite, and ferroxyhite) and additional compounds (atacamite and CN-containing compound). The scientific results, as well as the artist's statements concerning the patinas' significance, maintenance, and conservation, will contribute towards the future care and preservation of Canuti's sculptures. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Solvent- and water-borne fluoropolymer protective coatings for patina-free bronze discs. • Comparison of rheological, SEM, AFM, electrochemical and spectroscopic measurements. • Potentiodynamic polarisation revealed the improved performance of solvent-borne coatings. • Ex situ IR RA showed that hydration was greatest for the water-borne coatings. • In situ Raman suggested diffusion of lead from bronze alloy. Abstract Solvent- (SB) and water-borne (WB) fluoropolymer coatings were produced for the outdoor protection of bronze. The coatings were prepared from commercially available resins with alternating fluoroethylene/vinylether copolymers. Because any application of protective coatings on works of art requires that they be removable in accordance with conservation ethics, various approaches to achieve removability of coatings were tested. The influence of modifications was verified through comparisons of hydrophobic, compact and irremovable protective coatings. Consequently, we prepared four types of coatings: two SB coatings and two WB coatings. The first SB coating was designed to have a hydrophobic compact structure (SB-c coating), and the second SB coating was modified with the addition of agents that impart strippability (SB-h coating). The same approach was used for the preparation of the two WB coatings: a compact (WB-c) coating vs. a hydrophilic (WB-h) coating, the latter being prepared through the addition of hydrophilic polyisocyanate. The surface properties of the coatings were compared using scanning electron (SEM) and atomic force (AFM) microscopy. WB coatings were found to be more homogeneous in comparison with SB coatings and to have lower surface roughness. Contact angles confirmed the more hydrophobic nature of SB coatings. Potentiodynamic polarisation measurements and accelerated corrosion tests (exposure to acid vapours) revealed that protection efficiency not only increased with thickness but significantly depended on the coating structure. The structure of coatings depended on the rheological parameters of the formulations simulating their behaviour during storage, deposition, and formation of the dry coating. Combined electrochemical and vibrational spectroscopic experiments were used to simulate long-term outdoor exposure of the protective coatings. Ex situ IR RA spectroelectrochemical measurements showed that hydration was more prevalent with WB coatings, and oxidation of bronze at the interface eventually occurred (656 cm−1 band). WB coatings with more free C O groups were more prone to degradation. In situ Raman spectroelectrochemistry confirmed the better protection efficiency of SB over WB coatings. The optical properties of the coatings on glass showed higher transmittance for WB coatings compared to SB coatings. [ABSTRACT FROM AUTHOR]

In general, black patina is formed upon the surface of the ancient bronze mirrors. Recently, a kind of black patina is found on an ancient bronze sword, which was made 2500 years ago during the Warring States Period of China. In this paper, chemical compositions and microstructures of the black patina were characterized by using instruments including optical microscope (OM), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and Raman spectrometer (Raman). The results revealed that the formation of the black patina on the bronze sword is due to two reasons: (1) high tin (Sn) content reaches to 22.92 wt%; (2) damp, wet and acid burial environment. Therefore, it conforms to the natural corrosion formation mechanism, i.e., after selective dissolution of elements Cu and Pb from the matrix, element Sn was oxidized and then, the gel-like SnO 2 ·xH 2 O filled the vacancies left by the selective corrosion of Cu and Pb. This work will be helpful for better restoration and preservation of the bronze cultural relics. [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]

The corrosion products usually found on outdoor bronzes are generated by the interaction between the metal alloy and the atmospheric pollutants. To protect the external surface of bronzes, different organic materials (natural or synthetic) can be applied, creating over time a patina consisting of a complex mixture of inorganic and organic degraded components. The correct chemical characterization of patina constituents is fundamental to define the state of conservation of a metal artwork and address proper restoration actions. In this paper, we evaluated the potentialities of near-infrared (NIR) reflectance microscopy (4000-7500 cm−1) as complementary method to mid-infrared (MIR) analyses for the characterization of bronze patinas. Although NIR spectroscopy has been already used in the field of heritage science, its application for the characterization of bronze patinas is almost unexplored. In this paper, several corrosion products usually found on the surface of outdoor bronze sculptures were synthesized, characterized, and submitted to the NIR-MIR total reflection analysis to build up a reference spectral database. We devoted particular attention to the NIR features of copper hydroxychlorides, such as atacamite and paratacamite, which have not been studied in detail up to now. A selection of organic-based formulations, commonly used by restorers to protect the bronze surface against the outdoor aggressive environment, were also considered as references. Successively, NIR-MIR reflectance microscopy was successfully employed for the analysis of patina micro-samples collected from the bronze statues of the Neptune Fountain (sixteenth century) located in Bologna. The obtained results demonstrate the ability of NIR spectroscopy to identify organic and inorganic patina constituents, even in mixtures. In addition, the study can be considered as a proof of concept for the possible future application of the technique for in situ diagnostic campaigns on bronze sculptures. [ABSTRACT FROM AUTHOR]

Synthetic zinc patina was grown on galvanized steel sheets in supercritical carbon dioxide atmosphere. Different patina compounds were dissolved and quantified using a stepwise immersion and dissolution procedure. The distinct patina components, namely anhydrous zinc carbonate (a dense layer adjacent to metallic zinc) and zinc hydroxy carbonate (nanowires on the surface), were dissolved in glycine solutions, followed by quantification of Zn2+ in the solutes by X‐ray fluorescence. The zinc hydroxy carbonate nanowires were readily glycine soluble, and the anhydrous zinc carbonate showed scarce glycine solubility, which enabled their selective quantification. The amount of the remaining (anhydrous) zinc carbonate after glycine extraction was determined from the glycine‐soluble zinc oxide after calcination (heat treatment for 10 minutes at 350°C). The results were verified by scanning electron microscopy imaging and Fourier transform infrared spectroscopy measurements. [ABSTRACT FROM AUTHOR]

The article describes the petroglyphs in Surkhanddarya Province. Topics include the landscape consists of vast rocky outcrops and elongated low ridges up the dry riverbeds, comprising of stone soils with sparse vegetation; mentions that petroglyphs are not associated with any specific type of stone or the black patina deposits on various types of rocks; and also mentions the documentation of the petroglyphs was conducted in the same manner in both seasons of the research.

Naturally grown patinas are typically detected onto the surface of modern copper-based artefacts and strictly affect their surface reactivity and appearance. The production of representative patinas is a key issues in order to obtain model systems which can be used for the development and validation of appropriate conservation materials and methods. In this study, we have prepared different artificial representative patinas by using a quaternary Cu-Sn-Zn-Pb alloy with chemical composition and metallurgical features similar to those of valuable modern works of art. In order to produce degradation products usually observed onto their surface, chloride and sulphate species were used to induce corrosion processes. Different patinas were produced by changing the nature of corrosive species and the set-up for the accelerated degradation. The composition and structural properties of the patinas were investigated by attenuated total reflectance Fourier transform infrared spectroscopy, X-ray diffraction, optical microscopy and scanning electron microscopy combined with energy dispersive X-ray spectroscopy. The results allow to identify degradation products and to distinguish copper hydroxychloride polymorphs and copper hydroxysulphates with similar structure. Our findings show that patina composition can be tailored by modifying the degradation procedure and patinas representative of modern artefacts made of quaternary Cu-Sn-Zn-Pb alloy can be obtained. [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]

Heterocyclic organic molecules containing oxygen, nitrogen or sulfur are generally used as inhibitors for corrosion protection of copper. These compounds form protective films by adsorption onto the metal surface. Nevertheless, most such inhibitors are biologically toxic, hence there is a need for development of ecofriendly inhibitors. Chitin is a nontoxic biological polymer that is known to be enzymatically biodegradable. In the present study chitin was chemically modified to phosphorylated chitin (PCT) to make it soluble in aqueous medium and increase its complexing ability with metal ions. The ability of this modified polymer to inhibit corrosion of copper in aqueous NaCl and the nature of the inhibition process were investigated by gravimetric analysis, electrochemical impedance spectroscopy, and polarization measurements. X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX) analysis were used to examine the surface morphology and analyze the chemical composition of the film formed on the metal surface. Maximum efficiency of 92 % was achieved by addition of 200 ppm PCT as inhibitor to an aqueous corrosive environment containing 200 ppm chloride at 30 ± 0.1 °C. SEM studies revealed that the smoothness of sample surface was retained on PCT addition to the aggressive medium. EDX and XPS studies on the surface film revealed the presence of PCT. A plausible mechanism for the inhibition by PCT is suggested. [ABSTRACT FROM AUTHOR]

This work reports the first employment of a gel polymer-based electrochemical cell to perform electrochemical impedance analysis of archaeological remains. The patinas of three Roman coins are studied through of electrochemical techniques (especially Electrochemical Impedance Spectroscopy, EIS) along with Electron Scanning Microscopy (SEM-EDS) and X-ray diffraction (XRD), in order to validate the results obtained with jellified electrolyte. SEM-EDS and XRD analyses reveal the composition of the patinas suggesting that the original alloys were made of Cu and Cu–Sn–Pb. Furthermore, EIS results make one able to assess some characteristics of coins, as for instance, the presence of a noble patina . This outcome is corroborated by the SEM-EDS and XRD analysis, suggesting that the method based on the jellified electrolyte on archaeological samples can be employed. Moreover, supporting studies are carried out using Voltammetry of Microparticles (VMP), which is able to detect the presence of some specific corrosion products (cuprite). So far, EIS is not a common technique in the Cultural Heritage field despite it can provide useful information about the conditions of conservation, i.e., corrosion processes. Here we can show the advantages of developing a gel-based system for EIS measurement which allows carrying out a punctual and quick analysis on the ancient bronze roman coins. [ABSTRACT FROM AUTHOR]

Corrosion of copper pipes may release high amounts of copper into the water, exceeding the maximum concentration of copper for drinking water standards. Typically, the events with the highest release of copper into drinking water are related to the presence of biofilms. This article reviews this phenomenon, focusing on copper ingestion and its health impacts, the physicochemical mechanisms and the microbial involvement on copper release, the techniques used to describe and understand this phenomenon, and the hydrodynamic effects. A conceptual model is proposed and the mathematical models are reviewed. [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]

There is not only one methodology for the study of mineralogical phases in archaeological samples. In this paper, we discuss a strategy applied to ancient iron nail samples completely based on non-destructive analyses. The archaeological samples come from the archaeological site of Valle delle Forme (province of Brescia-Italy) and date back to the 1300-1400 ad. Neutron-based techniques, like time-of-flight neutron diffraction and neutron tomography, have been used to determine the mineralogical composition and the structure of nails. An independent check for the assessment of the presence of different mineralogical phases was given by Raman spectroscopy. The combination of different non-destructive techniques has provided very useful information on their chemical composition, nature of the patina and corrosion features of the nails (also in the bulk of the samples). [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]

We report here on the mechanisms underlying the corrosion of weathering steel in accelerated laboratory tests using artificially polluted SO-atmospheres. The role of corrosion parameters such as the SO concentration, the exposure time, the relative humidity and temperature of the environment are discussed in detail. Through the extensive use of Mössbauer spectroscopy in both its transmission and electron detection modes, as well as with the help of other analysis techniques, the characterization of the different corrosion products at the various stages of the corrosion process has been carried out. The results complement the data obtained in field studies and help to understand the mechanisms involved in this complex phenomenon. [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]

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]

The article focuses on a disc pipe, a multi-level pipe design that has on top a disc with a central hole that is placed above an elongated keel base in which the stem hole is drilled. It informs that the pipes are made from catlinite, which with use develops a deep dark patina. It cites the book "Tobacco Pipes and Smoking Customs of the American Indians" by George A. West that features several thousand exhaustively researched pipes.

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]

Copyright of Koroze a Ochrana Materiálu is the property of Sciendo 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.)

Lately there is a major concern about the preservation of artificial patina applied on the art objects made of bronze. These studies are important in the restoration and conservation of bronze monuments exposed outdoor. In this context the present work aims studying the efficiency of wax-based films (WF) on the protection of two artificial patina (brown and golden) in a solution containing Na2SO4 and NaHCO3 (pH 5) simulating an acid rain. The protective effect of the artificial patina with / without wax-based films was investigated by electrochemical and non-electrochemical methods. The chemical composition of the golden artificial patina/ Carnauba wax layer was determined by X - ray fluorescence analysis, and the morphology was determined by SEM - EDX cartographies. The results have shown that both artificial patinas exerted an anticorrosion protective effect on bronze and the wax improved even more the corrosion resistance. The protection conferred by the golden artificial patina was significantly improved by using Carnauba wax (Cw) and a corrosion inhibitor (2 - mercapto - 5 acetylamino - 1, 3, 4 - thiadiazole). [ABSTRACT FROM AUTHOR]

The 3.66 m tall and over nine-ton outdoor bronze sculpture of Alma Mater, created by Lorado Taft in 1929, is an iconic symbol of the University of Illinois at Urbana-Champaign. The conservation treatment of the sculpture came with some unexpected surprises, such as the discovery of failing internal ferrous nuts and bolts which needed to be replaced. The treatment involved removing the sculpture from its granite base, dismantling major elements of the sculpture and replacing the ferrous bolts with silicon bronze bolts, laser cleaning the surface with 1064 nm Q-switch scanning lasers, application of patina, applying a protective microcrystalline wax coating, and reinstallation of the sculpture. Analysis was performed with microscopy, X-radiography, and scanning electron microscopy. The conservation treatment involved cutting edge laser technology to remove corrosion from the surface, while structured light three-dimensional (3D) scanning and digital modeling techniques were used to create a new form of public interaction with the sculpture by 3D scanning the sculpture and creating a life like 3D digital model to create an augmented reality Alma Mater sculpture to temporarily take the place of the missing monument. Augmented reality is a technology which overlays a digital representation in registration with the real world giving the viewer an experience of interacting with the digital object as though it was actually present at that location in the real world. It is a longstanding tradition for students to have their picture taken with the sculpture during graduation, and thanks to this innovative use of technology, they were able to get their picture taken with a sculpture that was digitally, but not physically, present. In addition to receiving information and media related to the conservation treatment while it was taking place, the University of Illinois community and the class of 2013 was able to experience the augmented reality monument generated over the original base. This project demonstrates how augmented reality works of art can be used to replace the experience of actual objects that are removed from public view for conservation treatments. [ABSTRACT FROM AUTHOR]

CuCl patina was synthesized on bronze electrodes with electrochemical method. The inhibition effect and mechanism of l -cysteine (Cys) on bronze covered with CuCl patina have been studied with electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS) techniques. The EIS results show that Cys stabilized the CuCl patina to a great extent. The hydrolysis reaction of CuCl was inhibited effectively and an inhibition efficiency of over 90% was achieved. The XPS analyses indicate that the chemisorption of Cys molecules on CuCl surface occurred through sulfur atom in thiol and nitrogen atom in amino group. [ABSTRACT FROM AUTHOR]

This study is presents the results of systematic investigation of laser cleaning of corrosion or patina products on archaeological corroded objects. This aproach aiming to introduce a methodology for the optimal laser cleaning attitude in archaeological artefacts in Jordanian meuseums. It is study focused on the feasibility of YAG Laser in cleaning of Archaeological artefacts both organic and inorganic that covered with a corrosion or crust. The clustering of inclusion particles of the patina some are hard to remove by the procedure of conventional cleaning techniques, there is an apparent danger by use the traditional methods. These methods escalate the risk of the oxidised corrosion layer breaking away which will lead to loss of details about the the object and other important surface information. The advantage of using YAG pulsed lasers for cleaning of archaeological artefacts patina or corrosion. The lasr technique is well precised controlled and can be cleaned layer by layer or localizied. Thus, it is very significant to identify the chemical composition of the studied artifact surfaces before and after laser treatment. A series of laser cleaning studies has been done on test replica in the laboratory and artificially corroded. [ABSTRACT FROM AUTHOR]

'Dinheiros' are the first Portuguese coins, minted with a billon alloy (majority-based copper alloyed with silver). In this work, a set of 'dinheiros' from D. Fernando of Portugal was analyzed and the composition of the alloy was compared with other 'dinheiros' from previous reigns. Although the coins were in good state of conservation and no active corrosion was macroscopically observable, they still presented a corrosion layer of unknown thickness that would impair the XRF quantitative determinations. In order to overcome this hindrance, the silver K/L intensity ratios were determined and compared for the analyzed samples in order to choose 'clean' spots for quantitative analysis. The results show a clear decrease in the Ag content: from 7-9 % in the previous reigns to 0.2-0.3 % in the coins attributed to D. Fernando. The silver content determined is very comparable to the silver content determined in other copper or bronze artifacts analyzed, leading us to believe that this low amount of silver was not intentionally introduced to create a billon alloy but relates to impurities present in the original mineral specimen. [ABSTRACT FROM AUTHOR]

In this work we evaluate the composition of a bronze alloy using X-ray fluorescence spectrometry (XRF) and Monte Carlo (MC) simulations. For this purpose, a 7th Century BC archeological vase from the SW Iberian Peninsula, displaying a well formed corrosion patina was analyzed by means of a portable X-ray fluorescence spectrometer. Realistic MC simulations of the experimental setup were performed with the XRMC code package which is based on an intensive use of variance-reduction techniques and uses XRAYLIB a constantly updated X-ray library of atomic data. A single layer model was applied for simulating XRF of polished/pristine bronze whereas a two-or-three-layer model was developed for bronze covered respectively by a corrosion patina alone or coupled with a superficial soil derived crust. These simulations took into account corrosion (cerussite (PbCO 3 ), cuprite (Cu 2 O), malachite (Cu 2 CO 3 (OH) 2 ), litharge (PbO)) and soil derived products (goethite (FeO(OH)) and quartz (SiO 2 )) identified by means of X-ray diffraction and Raman micro analytical techniques. Results confirm previous research indicating that the XRF/Monte Carlo protocol is well suited when a two-layered model is considered, whereas in areas where the patina + soil derived products' crust is too thick, X-rays from the alloy substrate are not able to exit the sample. Quantitative results based on MC simulations indicate that the vase is made of a lead–bronze alloy: Mn (0.2%), Fe (1.0%), Cu (81.8%), As (0.5%), Ag (0.6%), Sn (8.0%) and Pb (8.0%). [ABSTRACT FROM AUTHOR]

This paper summarizes the experimental results concerning the Energy Dispersive X-ray Fluorescence (EDXRF) analysis of patinas on two Riace Bronzes, kept in the National Archaeological Museum of Reggio Calabria (Calabria, Southern Italy). The two large Greek sculptures, famous nude bearded warriors both dated in the fifth century BC, are without a doubt, two masterpieces of inestimable historic and artistic value. EDXRF survey had the aim to determinate the chemical composition of the surface of these two bronze statues and to discriminate their different patinas. In particular, the concentration of sulphur, chlorine, tin, manganese, iron, copper, zinc and lead was determined by using a portable apparatus. Multivariate statistical analysis was carried out in order to identify possible correlations and/or differences of elemental composition among the patinas of these two statues. The information obtained made it possible to improve knowledge about the patinas of the Riace Bronzes, and this may help further studies and subsequent methods of restoration and/or of preservation of the two celebrated Greek sculptures. [ABSTRACT FROM AUTHOR]

This essay reexamines the history of the preservation discourse that linked a monument's authenticity to the conservation of its patina. It puts this discourse in a broader intellectual context in order to show it to be related to changes in the Western cultural understanding of time, which were partially brought about by Henri Bergson's notion of duration. The idea that the nature of objects was to be in a state of perpetual change put into crisis the practice of restoring buildings to a past frozen moment in time and gave rise to the conservation of monuments in their "as found" condition. Important European preservation theorists such as Cesare Brandi, Paolo Torsello, Piero Sanpaolesi, and Paul Philippot debated how to express aesthetically the idea that monuments constantly change over time, despite being under a strict conservation regime. Their answers relied on the cleaning of surfaces and the limit of what was considered acceptable visual change. Their collective discourse theorized the patina as a discursive surface where preservationists were called on to express architecture's existence in time. [ABSTRACT FROM AUTHOR]

A quaternary (Cu-Zn-Sn-Pb) cast bronze was submitted to an electrochemical corrosion experiment using an anodic polarization sweep. The surface/interface chemical analysis of the patina removed after the anodic polarization and the metallographic observations on the corroded bulk alloy highlight the onset of a dezincification process followed by a decuprification process, aswell as the formation of a Sn-enriched layer located at the interface patina-bulk alloy. Different local corrosion patterns, as CuCl precipitation in pits, epitaxial growth of corrosion products on dendritic structures and of Cl-enriched oxyhydroxides, are observed too. The results are discussed in comparison with experimental findings obtained in previous ageing tests performed on the same alloy in different chloride-containing solutions. [ABSTRACT FROM AUTHOR]

A bronze bowl belonging to a private collection, stylistically consistent with the Achaemenid art was investigated to determine the cause of the artwork local fragmentation. The corrosion products were characterised by energy dispersive X-ray fluorescence spectrometry (EDXRF), Raman spectroscopy and scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS). The last technique was also used to determine the chemical composition of the alloy. The metallographic analysis showed that the bowl was obtained from a monophasic bronze alloy, containing about 11% tin and other elements in traces. The presence of an inhomogeneous microstructure with both thermal twin bands and slip lines was consistent with multiple hammering steps followed by partial annealing treatments. On the bowl a very limited chloride contamination was observed and chlorides were never detected in proximity to the metal. These findings and the morphological/compositional characteristics of the patinas permitted to classify that on the internal side of the bowl as a modified Type I morphology, while the patina on the external side of the bowl was less compact, so that it was judged borderline between a "noble" patina and a disfiguring one. On this side, a significant intergranular attack was found, reputed responsible for the fragmentation occurred. [ABSTRACT FROM AUTHOR]

The corrosion of bronzes was examined in the context of single-acid versus mixed-acid (as in urban acid rain) solutions. Two bi-component bronzes (copper with either 3% Sn or 7% Sn) that closely represent those of historic artifacts were immersed for five weeks in conditions designed to replicate those experienced by statues and ornaments in cities where rainfall and humidity constantly produce an electrolyte layer on the surfaces of bronzes. Ions, acids, and particles of pollutants can dissolve in this layer, resulting in a variety of harsh corrosion processes. The kinetics of corrosion and the properties of the resulting patinas were monitored weekly by electrochemical impedance spectroscopy and open-circuit potential measurements. The sizes and appearances of the corrosion products were monitored and used to estimate the progress of the corrosion, whose crystalline structures were visualized using scanning electron microscopy with energy dispersive spectroscopy, identified by X-ray diffraction, and characterized by spectrocolorimetry. The electrochemical measurements demonstrated that greater damage (in terms of color change and corrosion product formation) did not correspond to deficiencies in protection. The mixed-acid solution did not corrode the bronzes, as would be expected from the additive effects of the single acids. The postulated mechanisms of metal dissolution appear to be specific to a particular bronze alloy, with the tin component playing an important role. [ABSTRACT FROM AUTHOR]

The present work aims to investigate the corrosion behavior of bronze screws covered with natural patina used in assembling the statuary group of Mathias Rex, placed in the center of Cluj-Napoca, Romania, dating back to 1902. Corrosion tests were carried out in the absence and presence of inhibitors in a 0.2 g / L Na2SO4 + 0.2 g / L NaHCO3 (pH = 5) solution simulating an acid rain. The research put on evidence the inhibiting effect of 2 - mercapto - 5 acetylamino - 1, 3, 4 - thiadiazole on the naturally patinated artefacts in order to avoid their further degradation. The obtained results were compared with those recorded in the presence of benzotriazole, the most common corrosion inhibitor for Cu and bronze. [ABSTRACT FROM AUTHOR]