Artículos de revistas: "Corrosion patina"

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Crespo, Ana, Iván Díaz, Delphine Neff, Irene Llorente, Sagrario Martínez-Ramírez y Emilio Cano. "Effect of Sulfuric Acid Patination Treatment on Atmospheric Corrosion of Weathering Steel". Metals 10, n.º 5 (30 de abril de 2020): 591. http://dx.doi.org/10.3390/met10050591.

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The requirements for the formation of a protective patina on conventional weathering steels (WS) are well known in the scientific literature related to civil structures. However, these criteria are not always given due consideration when WS is used in cultural heritage, as in the case of sculptural work. An artificial patina was produced simulating artists’ working procedures using a direct patination technique, applying a solution of 10% H2SO4 on WS specimens. These were exposed for two years in the urban atmosphere of Madrid along with weathering steel specimens without artificial patina, called natural patina. The patinas generated have been analyzed using colorimetry, micro-Raman spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and thickness measurements.The artificial patina color formed hardly differs from the color that the natural patina acquires from practically the beginning of its formation in the atmosphere of Madrid. After two years, the atmospheric corrosion rate of patinated WS is lower than 6 µm/year. The sulfuric acid treatment accelerates the protective ability of the patina with respect to the natural patina according to the ratio goethite to lepidocrocite (α/γ). Chromium-rich goethite is located in the inner part of the artificial patina as well as chromium-rich ferrihydrite. Ferrihydrite may act as a precursor of nanophasic goethite.

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Li, Bingjie, Xudong Jiang, Yin Tu, Qiang Fu y Chunxu Pan. "“Inward Growth” Corrosion and Its Growth Mechanism in Ancient Chinese Bronzes". MRS Advances 5, n.º 27-28 (2020): 1457–66. http://dx.doi.org/10.1557/adv.2020.58.

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ABSTRACTWe divide the corrosion products on ancient bronzes into two categories, i.e., "inward growth" and “outward growth” corrosions. Several selected Chinese ancient bronzes with the "inward growth” corrosion are studied; and their chemical compositions, microstructures and morphologies are characterized systematically. According to the results, it is found that the “inward growth” corrosion can be further divided into three types, i.e., "noble patina", "noble-like patina" and "lamellar peeling patina". We propose that the growth mechanism of the “inward growth” corrosion is that the corrosion initiates at and develops along α-Cu phase. Furthermore, the effect of alloy Sn content on the “inward growth” corrosion is also studied.

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Myronyuk, I. F., I. M. Koval, V. I. Mandzyuk y I. P. Yaremiy. "Impurity Elements in a Lead Seals and Stamps of Middle Ages and Phase Composition of Their Patina". Фізика і хімія твердого тіла 17, n.º 3 (15 de septiembre de 2016): 430–34. http://dx.doi.org/10.15330/pcss.17.3.430-434.

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The paper studied the elemental composition of lead alloys of appendage stamps and seals of Middle Ages, and the influence of impurity elements in the alloy and conditions for long-term storage of monuments on the course of corrosion processes and the formation of patina phase composition. Due to the influence of salts of orthophosphoric, hydrochloric and carbonate acids dissolved in the water environment on the artifacts surface patina coating is produced formed mainly of pyromorphite or pyromorphite and lead carbonate mixture. It was found that the corrosion rate of monuments depends essentially on the total content of Zn, Cd, Sn and Fe in lead alloy, which provide the protect for the main metal due to the electrochemical oxidation. Pink and brown colour of patina of certain attractions is associated with the pink colour of pyromorphite, which it takes as a result of isomorphic substitution of a small number of Pb atoms on Fe (III) ones. A colour of patine coating also depends on the content FeO, FeOOH and PbCO3∙Pb(OH)2.

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Crespo, Ana, Gloria Pérez, José A. Jiménez, Irene Llorente, Sagrario Martínez-Ramírez, Emilio Cano y Iván Díaz. "Evolution and Evaluation of Aesthetic Properties in Weathering Steel Accelerated Patinas: The Role of Lepidocrocite". Metals 12, n.º 6 (7 de junio de 2022): 977. http://dx.doi.org/10.3390/met12060977.

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Weathering steels are widely used in civil engineering, architecture and contemporary art due to their mechanical properties, their enhanced resistance to atmospheric corrosion as well as their aesthetic properties. Artists and blacksmiths often apply chemical treatments to obtain the appealing colors of a patina in a shorter period of time. However, the development of an accelerated patina may have an effect on the final appearance and color of the surface. With the aim of evaluating differences in color and studying the evolution of the surface, eight accelerated patinas were made and exposed to the atmosphere for periods of time of up to 24 months and were compared to a natural patina. The characterization studies showed the presence of lepidocrocite on the surface. A close inspection of the X-ray diffraction patterns showed the displacement of the (020) lepidocrocite reflection and asymmetric broadening of selective lines of this phase that were associated to stacking and twins faults, respectively. These faults decrease with the exposure time and are related to a maximum at 630 nm in the reflectance spectrum and the stabilization of the b* coordinate (yellow color). The colors of the accelerated patinas differ from the natural patina at short exposure times. However, they tend to converge at longer exposure times.

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Papadopoulou, Olga y Panayota Vassiliou. "The Influence of Archaeometallurgical Copper Alloy Castings Microstructure towards Corrosion Evolution in Various Corrosive Media". Corrosion and Materials Degradation 2, n.º 2 (19 de mayo de 2021): 227–47. http://dx.doi.org/10.3390/cmd2020013.

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The local patterns at the interfaces of corrosion stratification, developed on two archaeometallurgical bronzes (a Cu-Sn-Pb and a Cu-Zn-Sn-Pb alloy), in the as-cast condition, were assessed by OM and SEM-EDS systematic elemental chemical analyses. Previously, the alloys—whose metallurgical features and electrochemical behaviour were already well studied—have been subjected to laboratory corrosion experiments. The corrosion procedures involved electrochemical anodic polarization experiments in various chloride media: 0.1 mol/L NaCl, 0.6 mol/L NaCl and two other synthetic chloride-containing solutions, representing electrolytes present in marine urban atmosphere and in the soil of coastal sites. The characterization of the Cu-Sn-Pb alloy electrochemical patinas after anodic sweep (OCP+ 0.6 V) revealed that the metal in all electrolytes undergoes extensive chloride attack and selective dissolution of copper which initiates from the dendritic areas acting as anodic sites. The most abundant corrosion products identified by FTIR in all electrochemical patinas were Cu2(OH)3Cl), Cu2(OH)2CO3 and amorphous Cu and Sn oxides. The characterization of the Cu-Sn-Pb alloy electrochemical patina after slow anodic sweep (OCP+ 1.5 V) in 0.1 mol/L NaCl reveals selective oxidation of dendrites and higher decuprification rate in these areas. Corrosion products of Sn-rich interdendritic areas are dominated by oxygen species (oxides, hydroxides, hydroxyoxides) and Cu-rich dendrites by chlorides. In the case of Cu-Zn-Sn-Pb, Zn in dendritic areas is preferentially attacked. The alloy undergoes simultaneous dezincification and decuprification, with the former progressing faster, especially in dendritic areas. The two processes at the alloy/patina interface leave behind a metal surface where α-dendrites are enriched in Sn compared to the alloy matrix. The results of this study highlight the dynamic profile of corrosion layer build-up in bronze and brass. Moreover, the perception of the dealloying mechanisms progression on casting features, at mid-term corrosion stages, is extended.

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Królikowska, Agnieszka, Leszek Komorowski, Izabela Kunce, Damian Wojda, Katarzyna Zacharuk, Urszula Paszek, Tomasz Wierzbicki y Katarzyna Bilewska. "Corrosion Assessment of a Weathering Steel Bridge Structure after 30 Years of Service". Materials 14, n.º 14 (6 de julio de 2021): 3788. http://dx.doi.org/10.3390/ma14143788.

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The first steel with improved resistance towards atmospheric corrosion, the so-called weathering steel, was patented in the USA in 1933 and was initially used for coal railway cars, and after that, in building and bridge engineering. Weathering steels show higher corrosion resistance than carbon steels in many types of atmosphere due to their ability to form a compact, stable, adherent and protective patina during the time of exposure. Morphological evaluation of the appearance of the corrosion product layer, together with phase analysis of its components, can enable determination of the type of patina and the degree of protection of the steel. To support the visual assessment of a patina, a check based on the qualitative and quantitative phase analysis of its components may be carried out, and the PAI (Protective Ability Index) can be calculated. The estimation of the corrosion processes on original Polish-made weathering steel (12HNNbA) was carried out on a 30-year-old bridge in Poland. There are some structural problems within the deck derived not only from corrosion but also steel cracking, both inside and outside the boxes, at different heights. Fourteen representative samples of patina were analysed and their phase structures were determined by the X-ray powder diffraction method. The PAIs were determined and analysed.

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Odnevall Wallinder, I. y C. Leygraf. "A Critical Review on Corrosion and Runoff from Zinc and Zinc-Based Alloys in Atmospheric Environments". Corrosion 73, n.º 9 (4 de mayo de 2017): 1060–77. http://dx.doi.org/10.5006/2458.

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This critical review aims at addressing important issues concerning zinc corrosion and zinc runoff processes of zinc or zinc alloyed with aluminum or magnesium exposed to atmospheric environments. The evolution of the corrosion product (patina) layer is very important for both processes. While corrosion largely is controlled by electrochemical reactions at the metal/patina interface, runoff is predominantly governed by chemical reactions at the patina/atmosphere interface. The gradual evolution of compounds in zinc patina follows one of two main routes: one in more sulfur-dominated and one in more chloride-dominated environments. Because of climatic changes and reduction of sulfur-containing atmospheric species in many parts of the world, the chloride-route is expected to dominate over the sulfur-route. Alloying with aluminum and magnesium results in substantial improvement in corrosion protection, whereby several mechanisms have been proposed. The released amount of zinc is highly dependent on the amount of rainfall, also on sulfur dioxide concentration or deposition, and to only a low extent on chloride deposition. Based on all runoff data, a model is presented which predicts 70% of all observed zinc runoff rates within 40% from their measured value.

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Kumaravel, D., V. K. Bupesh Raja, Kabasker Balthaser, A. Jayaganthan, S. Sahas, S. Muralidharan y Tariku Achamyeleh. "Investigation on Wear and Corrosion Behavior of Cu, Zn, and Ni Coated Corten Steel". Advances in Materials Science and Engineering 2022 (8 de octubre de 2022): 1–9. http://dx.doi.org/10.1155/2022/7341201.

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Corten steel is a low-carbon alloy steel. It is widely used in architecture, the transport sector, and industrial applications, where the steel is exposed to harsh environments. It is very much sought after due to its auto protection from corrosive environments through the formation of patina (rust). The specialty of patina formed on the corten steel is that it can self-heal itself and stop the spreading of corrosion. Generally, steels are given protective coatings to enhance resistance to corrosion, wear, abrasion, etc. One of the popular protective coating techniques is electroplating. In this study, the effect of electroplating of copper (Cu), zinc (Zn), and nickel (Ni) on the wear and corrosion behavior of Corten ASTM A242 grade steel is investigated. It was observed that the Cu coating yielded poor corrosion and wear protection performance. The Zn coating exhibited a moderate improvement. The Ni electroplating produced excellent results and, the wear and corrosion resistance was improved in the corten steel. Thus, when compared with Cu, Zn, and Ni coatings, the Ni-coated corten steel is an ideal candidate in applications where there is a need for good resistance to wear, abrasion, and corrosion.

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Es Sebar, Leila, Leonardo Iannucci, Yuval Goren, Peter Fabian, Emma Angelini y Sabrina Grassini. "Raman investigation of corrosion products on Roman copper-based artefacts". ACTA IMEKO 10, n.º 1 (31 de marzo de 2021): 129. http://dx.doi.org/10.21014/acta_imeko.v10i1.858.

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<p class="Abstract">This paper illustrates a case study related to the characterisation of corrosion products present on recently excavated artefacts. The archaeological findings, from the Rakafot 54 site (Beer-Sheva, Israel), consist of 23 coins and a pendant, all dating back to the Roman period. Raman spectroscopy was used to identify the corrosion products that compose the patina covering the objects. To facilitate and support their identification, spectra were then processed using principal components analysis. This chemometric technique allowed the identification of two main compounds, classified as atacamite and clinoatacamite, which formed the main components of the patinas. The results of this investigation can help in assessing the conservation state of artefacts and defining the correct restoration strategy.</p>

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Mikić, Dajana, Helena Otmačić Ćurković, Tadeja Kosec y Neven Peko. "An Electrochemical and Spectroscopic Study of Surfaces on Bronze Sculptures Exposed to Urban Environment". Materials 14, n.º 8 (20 de abril de 2021): 2063. http://dx.doi.org/10.3390/ma14082063.

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Polluted urban environment enhances dissolution of patina and underlying bronze material of recent and historical bronze sculptures exposed outdoors. In this work, two bronze statues, situated in one of the most polluted Croatian cities, were examined in order to characterize composition of patina and its electrochemical stability. The composition of patina on several positions on each sculpture was determined by EDS, Raman spectroscopy, and FTIR measurements. Electrochemical impedance spectroscopy measurements were conducted in order to evaluate the corrosion stability of both patina and underlying bronze. Results obtained in this work show that the two examined bronze sculptures were covered with patina layer that was mainly composed of copper sulfides and sulphates, which is in accordance with the high concentrations of H2S and SO2 in the atmosphere. However, the variations in the appearance of FTIR and Raman spectra revealed that the amount of each species differed from spot to spot, as well as the fact that other compounds, such as carbonates, were present at some areas. This difference in patina composition was reflected in electrochemical behavior as observed by electrochemical impedance spectroscopy.

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Vera, Rosa, Bárbara Valverde, Elizabeth Olave, Andrés Díaz-Gómez, Rodrigo Sánchez-González, Lisa Muñoz, Carola Martínez y Paula Rojas. "Corrosion Behavior of Copper Exposed in Marine Tropical Atmosphere in Rapa Nui (Easter Island) Chile 20 Years after MICAT". Metals 12, n.º 12 (4 de diciembre de 2022): 2082. http://dx.doi.org/10.3390/met12122082.

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Atmospheric corrosion of copper, exposed on a tropical island in the South-Central Pacific Ocean, was reported and compared with those of a very similar study at the same site conducted 20 years earlier. The new measurements—taken over three years of exposure, from 2010 to 2013—quantified corrosion by mass loss, characterized corrosion products by X-ray diffraction (DRX) and Raman techniques, observed the attack morphology by Scanning Electron Microscope (SEM), and evaluated the patina resistance using electrochemical techniques. The results showed a copper corrosivity category of C4, and the main copper patina compound, cuprite, was porous, nonhomogeneous, and thin. Electrochemical measurements showed cuprite layer growth as a function of the exposure time, and the morphology did not favor corrosion protection. Finally, when comparing the results to those of a study 22 years previous, the copper corrosion rates increased only slightly, even with increased contaminants associated with growing local populations and continuous tourism on the island.

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Mafalda, Ana Cardeira, Rodrigo Bettencourt da Câmara, Patrick Strzelec, Nick Schiavon, José Mirão, António Candeias, Maria Luísa Carvalho y Marta Manso. "White Spots on Smoke Rings by Bruce Nauman: A Case Study On Contemporary Art Conservation Using Microanalytical Techniques". Microscopy and Microanalysis 21, n.º 1 (27 de agosto de 2014): 15–19. http://dx.doi.org/10.1017/s1431927614013002.

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AbstractThe artwork “Smoke Rings: Two Concentric Tunnels, Non-Communicating” by Bruce Nauman represents a case study of corrosion of a black patina-coated Al-alloy contemporary artwork. The main concern over this artwork was the widespread presence of white spots on its surface. Alloy substrate, patina, and white spots were characterized by means of energy-dispersive X-ray fluorescence and scanning electron microscopy with energy-dispersive spectroscopy. Alloy substrate was identified as an aluminum alloy 6,000 series Al–Si–Mg. Patina’s identified composition confirmed the documentation provided by the atelier. Concerning the white spots, zircon particles were found on patina surface as external elements.

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Cockrell, Brian. "Colourful Corrosion: Black Bronze and its Enigmatic Patina". Papers from the Institute of Archaeology 19 (28 de octubre de 2009): 85. http://dx.doi.org/10.5334/pia.326.

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Salnick, Alex O. y Werner Faubel. "Photoacoustic FT-IR Spectroscopy of Natural Copper Patina". Applied Spectroscopy 49, n.º 10 (octubre de 1995): 1516–24. http://dx.doi.org/10.1366/0003702953965461.

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Fourier transform infrared photoacoustic spectroscopy (FT-IR/PAS) has proved to be a useful tool for nondestructive testing of copper corrosion layer (patina) formed in the atmosphere. The samples cut from a piece of the roof of the Stockholm City Hall were examined without any additional pretreatment. The components of the patina—brochantite Cu4(OH)6SO4, antlerite Cu3(OH)4SO4, and basic cupric carbonate Cu2CO3(OH)6 · H2O—as well as some other minerals were identified. The photothermal beam deflection (PBD) method was used for independent photoacoustic characterization of the samples. The depth profiling capability of FT-IR/PAS was used to determine the degree of photoacoustic saturation of the spectral bands and to evaluate the depth distribution of the main patina components. The technique thus compares favorably with more common approaches of patina examination which are more expensive and require special sample preparation.

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Pagano, Sabrina, Giuseppina Balassone, Chiara Germinario, Celestino Grifa, Francesco Izzo, Mariano Mercurio, Priscilla Munzi et al. "Archaeometric Characterisation and Assessment of Conservation State of Coins: The Case-Study of a Selection of Antoniniani from the Hoard of Cumae (Campania Region, Southern Italy)". Heritage 6, n.º 2 (16 de febrero de 2023): 2038–55. http://dx.doi.org/10.3390/heritage6020110.

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The paper presents the first archaeometric results on a selection of ancient Roman coins (antoniniani) from a treasure found in the Roman necropolis area of ancient Cumae (Southern Italy) during archaeological campaigns by the Centre Jean Bérard. A multi-analytical approach consisting of non-destructive techniques (stereomicroscopy, FESEM-EDS, pXRF, Raman, μ-CT) was implemented on the better-preserved coins of the treasure in order to investigate the chemical composition of the alloy. Chemical analysis showed that the Roman mint prepared the metal with an argentiferous lead–bronze alloy. A group of coins presents a low content of the precious metal, which is in agreement with the financial crisis of the Roman Empire of the third century. Another group of two coins shows a higher silver content, which is in agreement with their issue or with the Mediolanum mint standards. In addition, the external layers of corroded coins were analysed to explore the state of conservation of the patina and to identify the corrosion products. Some typical corrosion patinas due to post-depositional conditions were identified. The mineralogical characterisation of the corrosion products enables us to implement adequate conservation strategies, and the presence of more aggressive patinas suggests immediate interventions.

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González-Parra, Rafael, Alba Covelo, Arturo Barba y Miguel Hernández. "Electrochemical Polarization as a Sustainable Method for the Formation of Bronze Patina Layers on a Quaternary Copper Alloy: Insight into Patina Morphology and Corrosion Behaviour". Sustainability 15, n.º 3 (19 de enero de 2023): 1899. http://dx.doi.org/10.3390/su15031899.

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The bronze patina is aesthetically pleasing and enhances the corrosion resistance of the metallic object. This corrosion product layer can develop naturally, through aging or artificially. However, artificial methods require substances that are hazardous to human health and the environment. In this study, a sustainable approach to patina development, based on the anodic polarization of a 85.5Cu-4.2Pb-4.5Sn-5.7Zn copper alloy immersed in 0.1 M NaCl + 0.01 M NaHCO3 were characterized using polarization curves, chronoamperometry, electrochemical impedance spectroscopy, electrochemical noise measurements, X-ray diffraction, and scanning electron microscopy. The results indicate that the anodic potential modifies the current density as well as the diffusion coefficient of oxygen associated with a thicker corrosion product layer. Electrochemical Impedance spectroscopy and electrochemical noise show that the porous behaviour and corrosion resistance increases as the potential becomes more anodic due to the formation of a protective layer. This behaviour corresponded with the results acquired by chronoamperometry. The surface characterization shows that the potential applied changes the surface morphology and composition of the corrosion products, being identified the crystalline phases of nantokite and atacamite although Cu, Cl, O, Zn, and Pb elements were also detected.

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Fawcett, T. G., J. R. Blanton, T. N. Blanton, L. Arias y T. Suscavage. "Non-destructive evaluation of Roman coin patinas from the 3rd and 4th century". Powder Diffraction 33, n.º 2 (4 de abril de 2018): 88–97. http://dx.doi.org/10.1017/s0885715618000180.

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Roman bronze coins from the 3rd and 4th century AD exhibit a wide variety of chemistries on their surfaces. This variation has been attributed to the variable methods used to produce the coins, a large number of mints producing bronze currency, and the periods of currency devaluation within the Roman Empire. Besides the base bronze metallurgy (Cu,Sn), Ag, Pb, and Zn were frequently used as coinage metals. Silver coatings were often applied to increase the apparent value of the coins. Over the centuries these surfaces corroded producing a range of patinas. Non-destructive X-ray diffraction and X-ray fluorescence methods were used to evaluate ancient bronze coins. These methods are limited by their half depth of penetration into the coins, so the focus was on the chemistry of the patina's and how they related to the current appearance. Several 3rd-century bronze coins exhibited a very dark patina that was often composed of CuCl, Cu2O (cuprite) and several forms of copper hydroxyl chloride, resulting from surface deterioration caused by corrosion and is often referred to as bronze disease. Coins of the latter 3rd century and 4th century often exhibit patinas that are corrosion products of lead, silver, and tin, as lead and tin preferentially oxidize relative to the bronze alloys.

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Matyi, R. J. y R. Baboian. "An X-Ray Diffraction Analysis of the Patina of the Statue of Liberty". Powder Diffraction 1, n.º 4 (diciembre de 1986): 299–304. http://dx.doi.org/10.1017/s0885715600011970.

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AbstractAn X-ray powder diffraction analysis has been performed on several samples from the naturally occuring patina of the Statue of Liberty. This work, which was conducted as a service to the National Park Service as part of the restoration activities for the Statue, was performed to assess the impact of acid deposition on the phase composition of the patina. Samples of the patina that were obtained from various locations on the copper skin of the Statue were found to consist primarily of the basic copper sulfate known as brochantite or CuSO4·3Cu(OH)2. Another less stable form of basic copper sulfate CuSO4·2Cu(OH)2 known as antlerite was also observed in samples taken from areas that are more exposed to the incoming weather in New York harbor. The presence of antlerite supports the contention that acid deposition is promoting undesirable changes in the phase composition of the patina. Analyses were also performed on patina samples that were taken from pieces of the Statue's copper skin that had been removed in the years 1905 and 1980. X-ray powder diffraction of the corrosion product on the 1905 sample showed that it consisted primarily of the stable brochantite phase, while the 1980 sample displayed both copper chlorides as well as the less stable antlerite. Both samples also contained cuprite (Cu2O) which appears to have formed prior to either of the sulfates.

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Kapitanović, Angela y Helena Otmačić Ćurković. "The Effect of Corrosion Conditions on Aging of Artificial Patina on Three Bronzes". Coatings 12, n.º 7 (1 de julio de 2022): 936. http://dx.doi.org/10.3390/coatings12070936.

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The new bronze objects of art are almost always patinated before their exposure outdoors or indoors. Among the many patination methods used by practitioners, sulphide patination is one of the most common techniques. The aim of this work is to examine the corrosion behaviour of sulphide patinated bronzes under various aging conditions, including continuous immersion in simulated urban rain, alternating wet/dry cycles, and exposure to corrosion chamber with NO2 gas. The study was conducted on three types of bronzes with varying tin content. Corrosion characterisation of patinated bronze samples was performed by the means of electrochemical impedance spectroscopy and polarization measurements. Chemical composition and morphology of sulphide patinated bronze surface was examined by infrared spectroscopy and scanning electron microscopy. Obtained results show that freshly patinated bronze surfaces exhibit low corrosion resistance that gradually improves over time. An increase in corrosion resistance strongly depends on aging conditions, and it appears to be the highest under continuous immersion conditions.

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Mikić, Dajana y Helena Otmačić Ćurković. "Protection of Patinated Bronze with Long-Chain Phosphonic Acid/Organic Coating Combined System". Materials 16, n.º 4 (16 de febrero de 2023): 1660. http://dx.doi.org/10.3390/ma16041660.

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Bronze cultural heritage in urban areas is susceptible to decay due to the significant amount of pollutants present in the air. This causes the dissolution of bronze and the patina on its surface. The efficient protection of outdoor bronze cultural heritage is still an unresolved problem. The aim of this work is to investigate 16-phosphonohexadecanoic acid as an environmentally friendly and non-toxic corrosion inhibitor for patinated bronze. The corrosion protection of sulphide-patinated bronze by phosphonic acid alone and in combination with acrylic coating Paraloid B-72 is examined. In order to achieve efficient corrosion protection, various parameters of the phosphonic acid application were studied. The efficiency of protection is examined by electrochemical impedance spectroscopy (EIS) during the immersion in simulated acid rain solution and after exposure to a corrosion chamber. It was found that the studied phosphonic acid provides corrosion protection to patinated bronze and significantly improves the protective properties of Paraloid B72. This was also confirmed by scanning electron microscopy (SEM) examination of the coating surface after exposure to a corrosive environment.

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Bakirov, Bulat, Irina Saprykina, Sergey Kichanov, Roman Mimokhod, Nikolay Sudarev y Denis Kozlenko. "Phase Composition and Its Spatial Distribution in Antique Copper Coins: Neutron Tomography and Diffraction Studies". Journal of Imaging 7, n.º 8 (3 de agosto de 2021): 129. http://dx.doi.org/10.3390/jimaging7080129.

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The chemical and elementary composition, internal arrangement, and spatial distribution of the components of ancient Greek copper coins were studied using XRF analysis, neutron diffraction and neutron tomography methods. The studied coins are interesting from a historical and cultural point of view, as they are “Charon’s obol’s”. These coins were discovered at the location of an ancient Greek settlement during archaeological excavations on the “Volna-1” necropolis in Krasnodar Region, Russian Federation. It was determined that the coins are mainly made of a bronze alloy, a tin content that falls in the range of 1.1(2)–7.9(3) wt.%. All coins are highly degraded; corrosion and patina areas occupy volumes from ~27 % to ~62 % of the original coin volumes. The neutron tomography method not only provided 3D data of the spatial distribution of the bronze alloy and the patina with corrosion contamination inside coin volumes, but also restored the minting pattern of several studied coins. Taking into account the obtained results, the origin and use of these coins in the light of historical and economic processes of the Bosporan Kingdom are discussed.

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Nakayama, Shigeyoshi, Takenori Notoya y Toshiyuki Osakai. "Chemical State Analysis of Copper Corrosion Products Including Patina by Voltammetry". Zairyo-to-Kankyo 64, n.º 11 (2015): 508–13. http://dx.doi.org/10.3323/jcorr.64.508.

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Cho, Handong, Jeongwon Lee, Sangmin Lee y Woonbong Hwang. "Durable superhydrophilic/phobic surfaces based on green patina with corrosion resistance". Physical Chemistry Chemical Physics 17, n.º 10 (2015): 6786–93. http://dx.doi.org/10.1039/c4cp05590j.

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Marušić, Katarina, Helena Otmačić Ćurković y Hisasi Takenouti. "Corrosion Inhibition of Bronze and Its Patina Exposed to Acid Rain". Journal of The Electrochemical Society 160, n.º 8 (2013): C356—C363. http://dx.doi.org/10.1149/2.063308jes.

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Squarcialupi, Maria Cristina, Gian Piero Bernardini, Valentina Faso, Andrea Atrei y Gianfranco Rovida. "Characterisation by XPS of the corrosion patina formed on bronze surfaces". Journal of Cultural Heritage 3, n.º 3 (julio de 2002): 199–204. http://dx.doi.org/10.1016/s1296-2074(02)01179-2.

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Stupnisek-Lisac, Ema, Katarina Tadic, Helena Otmacic, Ana Dunja Mance y Hisasi Takenouti. "Corrosion Protection of Bronze Patina by New Non-Toxic Organic Inhibitors". ECS Transactions 2, n.º 9 (21 de diciembre de 2019): 31–42. http://dx.doi.org/10.1149/1.2408926.

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Scott, David A. "An Examination of the Patina and Corrosion Morphology of Some Roman Bronzes". Journal of the American Institute for Conservation 33, n.º 1 (1994): 1. http://dx.doi.org/10.2307/3179666.

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Manti, Panagiota y David Watkinson. "Corrosion phenomena and patina on archaeological low-tin wrought bronzes: New data". Journal of Cultural Heritage 55 (mayo de 2022): 158–70. http://dx.doi.org/10.1016/j.culher.2022.03.004.

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29

Scott, David A. "An Examination of the Patina and Corrosion Morphology of some Roman Bronzes". Journal of the American Institute for Conservation 33, n.º 1 (enero de 1994): 1–23. http://dx.doi.org/10.1179/019713694806066419.

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30

Urban, Viktor, Vit Křivý y Lukáš Fabián. "Experimental Testing of the Weathering Steel Road Bridge in Ostrava". Advanced Materials Research 849 (noviembre de 2013): 228–33. http://dx.doi.org/10.4028/www.scientific.net/amr.849.228.

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Weathering structural steel has been used for various outdoor load-carrying structures (even without anti-corrosion surface protection) in the world as well as in the Czech Republic for about 45 years [1, 2, 3]. Load-carrying structures are designed for service life of as many as 100 years and the weathering steel can be used as a standard structural material without any corrosion protection. The weathering steel is able to create a protective patina layer on the surface in favourable environment; it means suitable atmospheric and structural conditions. A lot of constructions built from the weathering steel in the Czech Republic have been assessed and inspected in last few years. This paper describes the new developed method for experimental measuring of real corrosion losses on typical surfaces of bridges.

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31

Lopesino, Patricia, Jenifer Alcántara, Daniel de la Fuente, Belén Chico, José Jiménez y Manuel Morcillo. "Corrosion of Copper in Unpolluted Chloride-Rich Atmospheres". Metals 8, n.º 11 (24 de octubre de 2018): 866. http://dx.doi.org/10.3390/met8110866.

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The atmospheric corrosion of copper in pure coastal atmospheres has not been extensively studied. This paper presents the results of research carried out in pure coastal atmospheres with annual chloride deposition rates of between 110–1640 mg/m2·d. Copper specimens (99.99 wt % Cu) were exposed for 3, 6, 9, and 12 months at six testing stations located at different distances from the seashore. Tests were performed to determine the copper corrosion rate, the surface area coated with corrosion products, and the evolution of both magnitudes with exposure time. Conventional and grazing X-ray diffraction techniques were used to analyze the corrosion products formed—cuprite and the polymorphs botallackite, atacamite, and clinoatacamite—and their presence through the patina thickness, while scanning electron microscopy/energy dispersive X-ray spectrometry was employed to study the morphology of the resulting corrosion layers. The most relevant findings are a notable increase in atacamite and clinoatacamite formation at higher atmospheric salinity levels and longer exposure times, and the flaking-off of the corrosion product layer formed in the marine atmospheres with the highest chloride deposition rates.

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32

Di Carlo, G., C. Giuliani, C. Riccucci, M. Pascucci, E. Messina, G. Fierro, M. Lavorgna y G. M. Ingo. "Artificial patina formation onto copper-based alloys: Chloride and sulphate induced corrosion processes". Applied Surface Science 421 (noviembre de 2017): 120–27. http://dx.doi.org/10.1016/j.apsusc.2017.01.080.

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Simancas, J., J. G. Castaño y M. Morcillo. "Corrosion and protection of metals in the rural atmosphere of "El Pardo" Spain (PATINA / CYTED project)". Revista de Metalurgia 39, Extra (17 de diciembre de 2003): 23–27. http://dx.doi.org/10.3989/revmetalm.2003.v39.iextra.1091.

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A., Gharib. "A SCIENTIFIC STUDY OF THE PATINA, CORROSION MORPHOLOGY, AND CONSERVATION OF EGYPTIAN BRASS OBJECT". Egyptian Journal of Archaeological and Restoration Studies 4, n.º 1 (1 de junio de 2018): 25–33. http://dx.doi.org/10.21608/ejars.2018.7271.

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35

Veleva, L. y M. Luja. "Scanning electron microscopy characterisation of copper corrosion products (patina) formed in tropical humid climate". British Corrosion Journal 34, n.º 1 (enero de 1999): 34–36. http://dx.doi.org/10.1179/bcj.1999.34.1.34.

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36

Qiao, Chuang, Lianfeng Shen, Long Hao, Xin Mu, Junhua Dong, Wei Ke, Jing Liu y Bo Liu. "Corrosion kinetics and patina evolution of galvanized steel in a simulated coastal-industrial atmosphere". Journal of Materials Science & Technology 35, n.º 10 (octubre de 2019): 2345–56. http://dx.doi.org/10.1016/j.jmst.2019.05.039.

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37

Di Fazio, Melania, Anna Candida Felici, Fiorenzo Catalli, Laura Medeghini y Caterina De Vito. "Micro and Nanoscale Structures and Corrosion Patterns in Brass: The Case Study of Ancient Roman Orichalcum Coins". Minerals 12, n.º 7 (29 de junio de 2022): 827. http://dx.doi.org/10.3390/min12070827.

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This study investigated the micro and nanoscale structure in Cu-Zn alloy, as well as its corrosion patterns. To achieve this goal, a set of Roman orichalcum coins were analysed using Scanning Electron Microscopy (SEM-EDS), X-ray maps, high resolution field emission scanning electron microscopy (HR-FESEM-EDS) and electron microprobe analyser (EMPA) techniques. The samples showed a high degree of corrosion on their external surfaces, which evolved in depth up to ~1 mm. Micro and sub-micro imaging of the inner metal highlighted the presence of “stressed areas” caused by mechanical processing work, representing the trigger zone of corrosion and causing the loss of material. These images also permitted us to follow the grain-grain interface and selective Zn-dealloying in the examined samples. X-ray maps of Cu and Zn helped us to understand the evolution of the dezincification process, from rim to core. HR-FESEM-EDS imaging investigation highlighted a heterogeneous composition within the strain line structures, confirming that the mechanically stressed areas were active zones for corrosion processes. Cracks and voids also characterised the patina. Conversely, the uncorroded cores of the samples were not affected by dealloying.

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Bottaini, Carlo E., Antonio Brunetti, Ignacio Montero-Ruiz, Antonio Valera, Antonio Candeias y José Mirão. "Use of Monte Carlo Simulation as a Tool for the Nondestructive Energy Dispersive X-ray Fluorescence (ED-XRF) Spectroscopy Analysis of Archaeological Copper-Based Artifacts from the Chalcolithic Site of Perdigões, Southern Portugal". Applied Spectroscopy 72, n.º 1 (20 de noviembre de 2017): 17–27. http://dx.doi.org/10.1177/0003702817721934.

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This work is part of a broader research line that aims to develop and implement a nondestructive methodology for the chemical characterization of archaeological metals based on a protocol that combines energy dispersive X-ray fluorescence spectrometry (ED-XRF) with a Monte Carlo (MC) simulation algorithm. In this paper, the ED-XRF-MC protocol has been applied to estimate the chemical composition of a selected group of 26 copper-based artifacts and fragments recovered at Perdigões, one of the larger Chalcolithic sites of southwest Iberia. All the analyzed artifacts have a multilayered structure composed of the alloy substrate and of a superficial layer common in each metal buried for hundreds of years and consisting of the patina mixed with soil. Due to the difficulty in determining the quantitative composition of these alloys in the presence of this complex patina/encrustation layer, the spectrometric protocol applied in this paper allows to simulate and to determine the composition of the bulk alloy without any prior removal of the overlying corrosion patina layer and soil-derived crust, even in the presence of rough and irregular surfaces, thus preserving the physical integrity of the artifacts. The overall results obtained with the ED-XRF-MC protocol indicates that the artifacts from Perdigões are almost pure coppers with a low amount of arsenic (<3.0 wt%) and reduced concentration of elements such as Pb, Bi, and Sb, in agreement with the third millennium metallurgy known in southwestern Iberia. Also based on previously theoretical–experimental studies, the data presented in this paper show how the applied analytical methodology can be a fast and completely nondestructive analytical tool reliable for routine and large-scale chemical analysis of archaeological metals, thus representing a major advance to be broadly applied within the field of cultural heritage studies.

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39

Bertling, Sofia, Inger Odnevall Wallinder, Dan Berggren Kleja y Christofer Leygraf. "LONG-TERM CORROSION-INDUCED COPPER RUNOFF FROM NATURAL AND ARTIFICIAL PATINA AND ITS ENVIRONMENTAL IMPACT". Environmental Toxicology and Chemistry 25, n.º 3 (2006): 891. http://dx.doi.org/10.1897/05-027r.1.

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40

Ion, Rodica-Mariana, Mădălina Elena David y Anca Irina Gheboianu. "Surface, Elemental and Electrochemical Characterizations of Ancient Coins By Non – Destructive Techniques". Scientific Bulletin of Valahia University - Materials and Mechanics 18, n.º 18 (1 de abril de 2022): 12–20. http://dx.doi.org/10.2478/bsmm-2022-0002.

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Abstract The cultural heritage field represents a witness to artifacts values in a continuous evolution, it strongly influences our sense of identity and our behavior as people. To protect these archaeological treasures, different conservation and restoration methods are required. Considering the field of priceless artifacts, our research direction led us to preliminary studies of metallic coins from 20th century through non–destructive techniques. Copper–based coins were subjected to the surface characterization through optical microscopy (OM) in transmitted light, elemental composition analysis using Wavelength Dispersive X-ray Fluorescence (WDXRF) and electrochemical corrosion using Tafel extrapolarization technique. The microscopic investigations showed that the patina layer is due to presence of copper content in coins composition confirmed by X-ray fluorescence spectroscopy technique. Also, the electrochemical tests disclosed different corrosion rate according to each chemical composition of coins. This study provide a broad overview of ancient coins to preserve their value in the future.

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41

Tsurumaki, Akiko, Cristina Chiarucci, Shraddha Khaire, Chiara Dal Bosco, Alessandra Gentili y Maria Assunta Navarra. "Removal of Copper Corrosion Products by Using Green Deep Eutectic Solvent and Bio-Derivative Cellulose Membrane". Polymers 14, n.º 11 (4 de junio de 2022): 2284. http://dx.doi.org/10.3390/polym14112284.

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A safe and environmentally friendly material for corrosion removal from metals is proposed in this article. Electrochemically corroded copper was selected as a target material, and a deep eutectic solvent (DES) composed of choline chloride and ascorbic acid, in a molar ratio of 2:1, was developed to this end. Aqueous solutions of the DES with a concentration above 70 wt% were found to be effective in the dissolution of patina and less aggressive towards other materials such as CaCO3, which is the main component of limestone. These concentrated DES solutions were integrated with either cotton swabs or cellulose-based membranes and used for the cleaning of electrochemically corroded copper. The membrane containing 80 wt% DES aqueous solution exhibited the most desirable cleaning ability in terms of speed and area selectivity. X-ray diffraction analysis of the corroded copper before and after the application of the membrane was performed to demonstrate the successful corrosion removal.

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42

Es, Sebar L., L. Iannucci, S. Grassini, E. Angelini, M. Parvis, R. Antonino, G. Quaranta, C. Giani, M. Boassa y M. Nicola. "Corrosion assessment of a bronze equestrian statue exposed to urban environment". Koroze a ochrana materialu 66, n.º 1 (1 de enero de 2022): 50–55. http://dx.doi.org/10.2478/kom-2022-0008.

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Abstract This paper presents the characterization of the conservation state of a bronze equestrian statue exposed outdoor, through an in-situ, multi-analytical, and non-invasive approach. The artefact under study is a bronze equestrian statue, devoted to Alfonso La Marmora, placed in an urban environment in the city of Turin. The investigation was carried out in the framework of a restoration intervention, with the principal aim of characterizing the overall conservation state of the sculpture to provide the conservators with information useful to develop a tailored restoration plan. X-ray fluorescence spectroscopy (XRF) was carried out for the identification of the elements present in the artefact alloy, showing that the statue was made using mainly two bronze alloys. Electrochemical Impedance Spectroscopy (EIS) was performed to study the corrosion mechanisms and to define the protective effectiveness of the patina present on the surfaces. Eventually, Raman spectroscopy (RS) was performed to characterize the chemistry and microstructure of the corrosion products, mainly identified as sulphates. The combination of these techniques allowed to confirm the presence of wax layers from previous restoration work, still capable to protect the metal substrate against corrosion. In addition, it was possible to correlate the conservation state to the exposure conditions and location on the statue.

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43

García-Ochoa, E. y F. Corvo. "Copper patina corrosion evaluation by means of fractal geometry using electrochemical noise (EN) and image analysis". Electrochemistry Communications 12, n.º 6 (junio de 2010): 826–30. http://dx.doi.org/10.1016/j.elecom.2010.03.044.

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44

Di Francia, Elisabetta, Ruth Lahoz, Delphine Neff, Emma Angelini y Sabrina Grassini. "Laser cleaning of Cu-based artefacts: laser/corrosion products interaction". ACTA IMEKO 7, n.º 3 (24 de octubre de 2018): 104. http://dx.doi.org/10.21014/acta_imeko.v7i3.610.

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<p class="Abstract">This study aims to develop a low invasive and selective laser cleaning procedure for the removal of reactive corrosion products on Cu-based artefacts without damage the substrate. In a preliminary step, laser cleaning was performed on two typologies of artificially corroded copper reference samples. The effect of the variation of laser parameters as pulse duration and output power, was thus evaluated on an oxide layer, simulating a protective patina, and a hydroxychloride layer, simulating a reactive corrosion products layer to be removed. The optimized cleaning procedure was validated on an archaeological artefact, a bronze coin. Morphological, microchemical and microstructural characterizations were performed by means of optical microscopy, confocal microscopy, field emission scanning electron microscopy, X-Ray diffraction and Raman spectroscopy, before and after laser cleaning. The experimental findings show that laser cleaning, in optimized conditions, can reduce the thickness of the hydroxychloride layers slightly affecting the oxide layers. The difference in the interaction with laser radiation of these two layers seems to be mainly related to the difference in grain size and porosity. Notwithstanding these encouraging results, in order to define the real feasibility of the laser cleaning procedure, a further validation on real artefacts is mandatory due to the variation in thickness and composition of the corrosion products formed during long-lasting uncontrolled degradation processes.</p>

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45

Brunetti, Antonio, Marta Porcaro, Sergio Lins, Francesco di Gennaro, Rosario Maria Anzalone, Mario Mineo y Anna Depalmas. "The Strange Case of the Nuragic Offerers Bronze Statuettes: A Multi-Analytical Study". Materials 15, n.º 12 (13 de junio de 2022): 4174. http://dx.doi.org/10.3390/ma15124174.

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The Nuragic civilization (Sardinia, Italy, XVIII–VIII B.C) developed a flourishing bronze metallurgy with strong connections with other civilizations from the Mediterranean basin. Within the large bronze production, there are some peculiar representations of human figures, known in the archaeological environment of Sardinia as bronzetti, depicting warriors, priests, and offerers. In this paper, an interesting couple of Nuragic statuettes representing offerers, one from the Pigorini Museum in Rome and another from the Musei Reali in Turin, were analyzed. They have been investigated with X-ray fluorescence integrated with Monte Carlo simulations (XRF-MC). The combined methodology provides more accurate results, ranging from the structural characterization to the identification of the corrosion layers to the estimation of the composition of the alloy of the artifact. One of the most striking results regards the heads of the offerers: both heads are covered with a thick iron-based layer, even though the whole artifacts are made of a copper alloy. To understand the reason behind this peculiar corrosion patina, several hypotheses have been considered, including the possibility that these iron mineralizations are the consequence of an ancient superficial treatment, intending to confer a chromatic effect on the figurine’s head.

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46

Li, Shuangyi, Baosen Hou, Dan Dai, Shengcheng Shu, Mingliang Wu, Ao Li, Yu Han et al. "CVD Synthesis of Monodisperse Graphene/Cu Microparticles with High Corrosion Resistance in Cu Etchant". Materials 11, n.º 8 (17 de agosto de 2018): 1459. http://dx.doi.org/10.3390/ma11081459.

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Copper powder has broad applications in the powder metallurgy, heat exchanger, and electronic industries due to its intrinsically high electrical and thermal conductivities. However, the ease of formation of surface oxide or patina layer raises difficulty of storage and handling of copper powder, particularly in the case of Cu microparticles. Here, we developed a thermal chemical vapor deposition chemical vapor deposition (CVD) process for large-scale synthesis of graphene coatings on Cu microparticles, which importantly can remain monodisperse without aggregation after graphene growth at high temperature by using removal spacers. Compared to other protective coating methods, the intrinsic electrical and thermal properties of Cu powder would not be degraded by uniform growth of low defect few-layer graphene on each particle surface. As a result, when the anticorrosion performance test was carried out by immersing the samples in Cu etchant, the corrosion rate of graphene/Cu microparticles was significantly improved (ca three times slower) compared to that of pristine Cu powder, also showing a comparable anticorrosion ability to commercial CuZn30 alloy.

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47

Kiele, Erika, Jurate Senvaitiene, Asta Grigucevicienė, Rimantas Ramanauskas, Rimantas Raudonis y Aivaras Kareiva. "Sol-gel derived coatings for the conservation of steel". Processing and Application of Ceramics 9, n.º 2 (2015): 81–89. http://dx.doi.org/10.2298/pac1502081k.

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In this paper, sol-gel processing route has been applied and investigated for the conservation of steel. Nanosilica coatings on steel surface have been prepared using tetraethylorthosilicate (TEOS) as a starting material. The methyl-modified silica sols were obtained by mixing of 3mas.% SiO2 sol solution with hexamethyldisilozane (HMDS). The surface of steel was coated by dip-coating technique. In order to compare the characteristics of coatings, the steel substrates were also coated with commercial polymers Paraloid B67, Cosmolloid H80 and Antik Patina. The surface morphology changes of the uncoated and coated specimens before and after photochemical ageing were investigated by scanning electron microscopy and atomic force microscopy. The structure of the prepared coatings was also investigated by FTIR spectroscopy. The hydrophobicity of surfaces was evaluated by contact angle measurements. Potentiodynamic measurements were obtained in order to compare corrosion parameters of the coatings.

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48

Wang, Tianran, Julin Wang y Yuqing Wu. "The inhibition effect and mechanism of l-cysteine on the corrosion of bronze covered with a CuCl patina". Corrosion Science 97 (agosto de 2015): 89–99. http://dx.doi.org/10.1016/j.corsci.2015.04.018.

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49

Salmen, Björn Torsten, Marina Knyazeva y Frank Walther. "Development of a Structural Integrity Non-destructive Inspection System for Bridges Made of Weathering Steel". MATEC Web of Conferences 278 (2019): 03006. http://dx.doi.org/10.1051/matecconf/201927803006.

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Due to the increasing volume of traffic, bridges are exposed to higher loads as it was considered during the planning phase. Therefore, a regular inspection is necessary in order to detect cracks at very early stages. The use of weathering structural steel in bridges, as well as in composite bridge constructions is an alternative to conventional bridges, not only from an economic but also from an ecological point of view, since it is not necessary to apply a corrosion protection layer and renew it during the lifetime of the bridge. Unfortunately, conventional visual inspection or magnetic particle inspection on the weathering steel bridge are hindered by the protective patina and requires development of new test methods. Within the framework of this project, a combined crack detection technique using non-destructive inspection by means of Active Thermography and by Electro-Magnetic Acoustic Transducer (EMAT) were evaluated in laboratory environments and in real conditions on bridge structures made of weathering structural steel.

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50

Abbas, Mahmoud, Rehab M. El-Maghraby, Esraa Hassan y Reda F. M. Elshaarawy. "Improving the Corrosion Resistance of Tin-bronze by Surface Modification". Journal of University of Shanghai for Science and Technology 23, n.º 09 (29 de septiembre de 2021): 1270–81. http://dx.doi.org/10.51201/jusst/21/09666.

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Bronze alloys are made of copper-based materials with another metal, usually tin. Many surface modification techniques such as chemical etching, oxidation, electro deposition and sol-gel could be employed to improve surface properties. The organic compound that was used in this study was extracted from chili peppers. FT-IR (Fourier-transform infrared) spectroscopy and UV (Ultraviolet) spectroscopy investigations were applied on the extracted compound and results showed that this compound is mainly capsaicin [N-(4-hydroxy-3-methoxybenzyl)-8-methylnon-trans-6-enamide) (HMMTE)]. Electrochemical deposition was employed under cell voltage equal to 30 volts in a two-electrodes cell where bronze was the anode and stainless steel was the cathode in a solution of 10 ml/L (HMMTE)/distilled-water. Modification of tin-bronze for 1 hr. in 10 ml/L HMMTE/ distilled water solution increased the contact angle from 48° to 132˚. Attension Biolin device (Model: Theta Optical Tensiometers) was used to measure the contact angle at ambient temperature. Electrochemical measurements revealed that a significant improvement in corrosion resistance of tin-bronze in 3.5% NaCl had been achieved. The corrosion rate of tin-bronze decreased from 10.22 mpy to 1.39 mpy. Surface morphology of the samples was investigated with scanning electron microscopy (SEN) and energy-dispersive X-ray (EDX). X-ray diffraction was employed to determined present phases. Surface investigations results confirmed that a layer of red cuprous oxide (Cu2O) was formed on the surface layer after modification which led to the improvement in corrosion resistance. Salt spray test was carried out using Alpha+ Salt Spray Testing Equipment for 13 days on the base and surface modified samples according to ASTM B117. A green layer from [CuCl2 and Cu46Cl24(OH)68-(H2O)4] was observed on the nonmodified specimen (could be patina and bronze disease) while the red layer [Cu2O] is still observed on the modified specimen. Adhesion test (using X-Cut Tape Adhesion test according to ASTM D3359) was also investigated.

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