Copper Pigments Research Articles

Funkcionalizacija tekstilnih materijala korišćenjem premaza i pigmenata koji sadrže bakar

Copper is one of the most used industrial metals. Also, copper containing compounds have high importance in everyday life. The use of copper and its compounds for textile treatment and functionalization is possible by using a broad range of different methods; as e.g. electrodeposition, plasma deposition, spin-doping with copper containing pigment or dye applications using copper salts as mordants or complexing agents. This actual report focusses especially on the use of copper containing pigments applied as part of a coating or a print onto textile surfaces. A general introduction into different types of copper compounds is given. Examples are given for the application of coatings containing copper effect pigments, gold bronze, elemental copper pigments and copper oxide particles. Related to effect pigments, especially silver coated copper pigments are introduced. According to sol-gel applications for textile functionalization, the in-situ preparation of copper oxide nanoparticles on textile surfaces is discussed. Following an overview on possible functionalization as result of the copper application is given. Antimicrobial and antistatic properties are discussed and presented with examples. The determined effects in this field are significant but less compared to analogous functionalization using silver as functional compound. A view on optical modifications and realized UV-protective properties is given. Finally, it can be stated that copper containing materials can be helpful tools to functionalize textile materials and surfaces in a broad range.

Tiles from Aosta: A Peculiar Glaze Roof Covering

The 18th century roof tiles from the “Casa delle vigne”, located in the Aosta region (north-east Italy), were investigated as an example of a peculiar historical roof covering: ceramic tiles with a lead-based glaze finishing to waterproof them are used to create colourful patterns. A conservation project proposed the integration of the original tiles with new ones, produced according to traditional methods. Ancient and new tiles were analysed with Fiber Optics Reflectance Spectroscopy, micro-Raman, Fourier Transform Infrared Spectroscopy and X-ray Fluorescence Spectrometry, Thermogravimetry and Differential Scanning Calorimetry for understanding the composition and the production technology of this manufacture. Their resistance to freezing and thawing cycles was then tested, considering their exposure in the severe alpine climate of Aosta. The use of pure clays with low calcium contents, high firing temperature and lead-rich glazes was found in ancient tiles, able to outstand several freezing-thawing cycles without damages. Iron and copper pigments were used in old yellow and green glazes. Zinc-based pigment, low lead and calcium-rich glazes are used in the new ones, which remained mainly coherent to the ceramic body during the freeze-thaw test.

Caravaggio's copper

AbstractSt. John the Baptist in the Wilderness, commissioned for the private chapel of Genoese banker. Ottavio Costa in 1602/3 and now in the collection of the Nelson‐Atkins Museum of Art (#52‐25), provides an important opportunity to understand Caravaggio's use of materials from one of his best‐preserved paintings. macro‐X‐ray fluorescence (MA‐XRF) elemental mapping has now been used to build upon a 2016 stratigraphic study of the palette employing optical and UV fluorescence microscopies, scanning electron microscopy‐energy dispersive X‐ray spectrometry (SEM‐EDS), Raman spectroscopy, and polarized light microscopy. The combined results of these methods clarify aspects of the iconography that have previously been obscure and expand our understanding of the roles of the various pigments. The roles for copper‐based pigments are surprisingly diverse for a painting with few obvious green and blue passages, in which many greens are based on terraverte. Darkening of the foliage adjacent to the figure of St. John has long posed interpretive difficulties, due to poor legibility of the plants depicted there. The foliage has been clarified by the results of MA‐XRF mapping, which distinguish the plant species by the palette choices involved in their depiction. Copper pigments play a fundamental role in Caravaggio's work, shading and modulating complementary colors with the additional practical benefit of playing a siccative role in paints that would otherwise dry poorly. MA‐XRF mapping has also revealed a role for copper pigment used to lay out the composition that was not apparent through radiography or infrared imaging methods.

Examining the Corrosion Behavior of The 6061-T6 Al Alloy Inside Seawater With Decorative Gold- And Silver-Color Coating

This study examined the corrosion resistance of the metallic paint-coated, uncoated, and damaged paint-coated form of the high-strength 6061 T6 Al alloy inside seawater. Solvent-based paint containing two different metallic pigments produced with an alkyd binder was produced and the coating of Al 6061 T6 alloy was made with this paint. To determine the course of corrosion electrochemical impedance spectroscopy method was used. Ecor and Rp values were calculated from potential and current change values. As a result, it was determined from the Ecor, Rp, SEM -EDX images, and Nyquist curves that the corrosion resistance of impact coatings was lower. The corrosion resistance of gold color paint substantially containing copper pigment was lower than that of silver color paint containing Al pigment was observed.

Pigment composition in the privilegio rodado of Juan the Second

The article examines the pigments used in the design of the privilege of King Juan II of Castile and Leon to his favorite Alvaro de Luna for a third part of the city of Arevalo. The charter comes from the collection of Academician Nikolai Petrovich Likhachev (1862-1936), held at the St. Petersburg Institute of History of the Russian Academy of Sciences. The document belongs to the most solemn type in the Royal Chancellery of Castile; its formula was extremely stable, while its exterior design was dynamic. The design consists of three parts: the initial, the rueda and the border. The study of pigments of was carried out by optical microscopy, multispectral imaging and X-ray fluorescence analysis. It was found that, contrary to the prevailing opinion in the literature, the pigments were placed on the parchment without any ground or pre-drawing. It was found that both mineral and organic pigments were used. Different pigments were used in different elements of the decoration of the charter. The rueda and initial form one group, the border another. In the first group, red is obtained using pure cinnabar or a mixture of it and red lead. Blue and pink are formed by organic dyes in combination with lead white. The traditional Western European azurite and lapis lazuli are not used. The green is most likely a mixture of orpiment and indigo. This combination was not typical of Western European illuminations of the Late Middle Ages. Copper pigments were more common during this period. Black pigment is represented by soot, white by lead white. Green, on the other hand, is represented by copper pigments in the border, while blue and pink contain no lead. The difference in pigments set may indicate two different stages of the fabrication of the charter, different in time and place. A study also confirmed the use of natural gold, which is consistent with the high status of the recipient of the privilege, Alvaro de Luna, who played an important role in the Castilian court. Refs. 30.

Spectroscopic study of mixtures of green copper pigments in fresh and aged model samples. Case studies on masterpieces from the Spanish Golden Age

Spectroscopic study of mixtures of green copper pigments in fresh and aged model samples. Case studies on masterpieces from the Spanish Golden Age

Antimony and Nickel Impurities in Blue and Green Copper Pigments

Impurities in paint layers executed with green and blue copper pigments, although relatively common, have been studied only little to date. Yet, their proper identification is a powerful tool for classification of paintings, and, potentially, for future provenance studies. In this paper, we present analyses of copper pigments layers from wall paintings situated in the vicinity of copper ore deposits (the palace in Kielce, the palace in Ciechanowice, and the parish church in Chotków) located within the contemporary borders of Poland. We compare the results with the analyses of copper minerals from three deposits, two local, and one historically important for the supply of copper in Europe, i.e., Miedzianka in the Holy Cross Mountains, Miedzianka in the Sudetes, and, as a reference, Špania Dolina in the Slovakian Low Tatra. Optical (OM) and electron microscopy (SEM-EDS), Raman spectroscopy, and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) have been used for a detailed investigation of the minute grains. Special attention has been devoted to antimony and nickel phases, as more unusual than the commonly described iron oxides. Analyses of minerals from the deposits helped to interpret the results obtained from the paint samples. For the first time, quantitative analyses of copper pigments’ impurities have been described.

Thermal Camouflage Clothing in Diurnal and Nocturnal Environments

This paper shows the possibility to thermally camouflage a human body in a beach environment, during the day and at night, through the use of two knitted fabric clothing prototypes. The conceptual design process applied was initially developed based on the need to firstly understand the behaviour of an individual dressed under the focus of a thermal imaging camera in the light of the infrared spectrum. The thermal tests undertaken to observe the model's thermal camouflage in certain positions/perspectives in both environments, enable simultaneously running of different solutions while introducing changes to the clothing. Printing with copper pigments and the patchwork using stitched structures in polyester knitted fabric played a decisive role to capture the thermal colours of the thermal image intended for the camouflage effect.

Stabilisation Treatments for Paper with Green Copper Pigment Verdigris

Abstract The focus of this research is the stabilisation of paper with Verdigris, a green copper pigment. Due to its corrosive effects on paper, many important documents, paintings and maps are in danger. The efficiency of several commercially available deacidification agents on paper samples with Verdigris was tested, including magnesium-based Bookkeeper® dispersion, nano calcium hydroxide containing Nanorestore® and CaLoSiL® dispersions as well as a recently developed dispersion of nano calcium carbonate. The antioxidant tetrabutylammonium bromide was tested either alone or in combination with nano calcium based deacidification agents. The effect of the treatments was evaluated using colour, tensile strength, degree of polymerization and pH measurements. The results indicate that acidic degradation does not play a major role during accelerated degradation of paper containing Verdigris with moderately acidic pH value and that oxidative decay could be the main culprit of the decay. The method described, which involves the use of antioxidant tetrabutylammonium bromide in combination with calcium carbonate based deacidification dispersion, was proved to have a superior effect against degradation of paper with Verdigris in comparison to the treatments which involve deacidification agents only. Nano calcium hydroxide based deacidification agents result in high pH values of the paper samples and therefore cannot be advised for use on paper documents.

Novel Procedure for Brochantite Based Pigment Production and Its Immobilization for Restoration of Historical Copper Objects

The article deals with the preparation of artificial copper pigment based on brochantite. The pigment was prepared by slow additions of sodium hydroxide solution into the solution of copper sulphate. The studied parameters were addition rate, solutions concentrations, ferrous ion addition, and filtration time. The prepared pigments were evaluated by means of X-ray diffraction and spectrophotometry. Subsequent pigment immobilization in an acrylate varnish was also studied. Observed parameters were influenced by solvent type, mechanical or chemical dispersion, and natural aging in an aggressive outdoor atmosphere. Pigment containing varnishes were evaluated by means of spectrophotometry, optical profilometers, and pull-off test. Slow hydroxide addition allows the formation of brochantite pigment. Fast filtration limits backward pigment decomposition. Ferrous ion improves pigment color closer to natural copper patina. The ideal immobilization procedure includes ethylacetate as a solvent and mechanical dispersion. The varnish filled with pigment provides sufficient adhesion to the metallic copper substrate as well as long-term color stability in the outdoor atmosphere.

Reaching for copper pigments speciation with High Resolution Energy Dispersive PIXE

The C2TN XMS-PIXE system based on a first generation X-ray Microcalorimeter Spectrometer (XMS) having 1.5% relative energy resolution at Si Kα 1.739 keV and 0.5% relative energy resolution at Fe Kα 6.403 keV, became operational in 2008, presaging various developments to emerge from its use and from connected or related but independent advancements by other laboratories. More than ten years having passed since the C2TN XMS-PIXE system first results, knowledge about XMSs use for PIXE has grown meaningfully and new applications are now envisaged and in progress. In the present work, results on the analysis of different copper compounds are presented, and used as an assessment of the capacity of High Resolution Energy Dispersive PIXE (HiRED-PIXE) to provide answers to the problem of copper pigments speciation in Cultural Heritage studies. Related issues of XMS spectra generation and calibration are discussed, as well as first generation systems limitations and its overcome by the use of second and third generation systems.

Photochemical Origin of the Darkening of Copper Acetate and Resinate Pigments in Historical Paintings.

Copper acetate and copper resinate pigments are bimetallic CuII complexes in which metal atoms are bridged by four carboxylate ligands (acetate or abietate). Prepared with lindseed oil as binder, these green pigments were particularly used in easel paintings between the 15th and 17th centuries. Unfortunately, they had the tendency to darken in an irreversible way, explaining why they fell into disuse. The darkening mechanism of films of copper pigments in linseed oil is studied by electron paramagnetic resonance (EPR) and by optical absorption spectroscopy (OAS). EPR and OAS reveal different chemical and photochemical behaviors depending on the type of copper complex and on the binding oil. The effect of light is investigated by illuminating the films at ∼410 nm in the bridging ligand-to-metal charge transfer (LMCT) transition. The photodarkening manifests itself as the appearance of an optical absorption band around 22 000 cm-1 and a decrease of the EPR intensity of bimetallic copper complexes. These effects are explained by the photoinduced substitution of acetate (or abietate) bridging ligands by dioxygen molecules from ambient atmosphere. The resulting peroxo-CuII dimer is characterized by a red shift of the LMCT and an increase of the exchange interaction in the ground state, which is responsible for the decrease of the EPR intensity due to the depletion of the paramagnetic S = 1 state. This mechanism explains the differences in darkening intensity observed with different pigment compositions (resinate versus acetate, raw linseed oil versus boiled linseed oil).

Characterization of copper-based pigment preparation and alteration products

ABSTRACTCopper-based pigments are common in works of art that show signs of decay on green and blue areas and are frequently associated with the degradation of organic substrates and/or media (drying oils, cellulose, etc.). The exact causes of degradation remain unknown. This prompted us to study possible starting and degradation products of one especially reactive copper pigment, verdigris (copper acetate), as well as pigments of the same family (salt and soap greens). Preparation of pigments using historical methods was followed by spectroscopic and crystallographic characterization using Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Synthesis of verdigris and verdigris-like pigments resulted in a mixture of starting polymorphs of verdigris, including neutral and basic verdigris. With accelerated aging, pigments degraded to a polymorph of basic verdigris when not affected by organic media, whereas pigments on cellulosic substrates showed oxidized copper species. With this study, we are beginning to understand verdigris starting materials and highlight the complex interactions between pigments and substrates that influence pigment degradation pathways.

Comparison studies on the anticorrosion and overall performance of solvent/water based epoxy-copper reinforced composite coatings

The influence of using two types of carrier agent namely, water and solvent, on the overall performance of epoxy resin has been investigated. Furthermore, four different loading rates of copper pigments (Cu) have been successfully embedded into two developed polymeric matrices and the changes occurred in the structure, thermal, fouling ability, morphology, and the anticorrosion performance have been studied. Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), field immersion test, scanning electron microscope (SEM), and electrochemical impedance spectroscopy (EIS) were used to evaluate the formulated coating systems. The results revealed that, the incorporation of Cu pigments did not significantly affect the efficiency of the room temperature curing process and further led to enhancement on the thermal stability of both developed epoxy resins. However, utilizing Cu pigments with solvent based epoxy (SB) showed better antifouling and anticorrosion properties compered to Cu composites prepared with water based epoxy resin (WB). The electrochemical behavior up to 30 days of immersion in 3.5% NaCl solution confirmed that the SB resin loaded with Cu pigments at 10% PVC, SB 10, demonstrated excellent barrier and anticorrosion properties. Neat WB coating (WB 0) was found to have the best performance among all WB coating systems.

Study of Mexican Colonial Mural Paintings: An In-situ Non-Invasive Approach

ABSTRACTColonial mural painting developed in Mexico in XVI century after the conquest of the pre-Hispanic cultures following the evangelization process little information exists about the chronology of the paintings and workshops, the painters, the pictorial techniques or the materiality of this art work.In this work, we present the non-invasive methodology of study of the pigments and other components of nine mural paintings in three colonial Augustinian ex-convents located in Epazoyucan, Actopan and Ixmiquilpan, in the state of Hidalgo, central Mexico. These places were selected not only because of the inherent value and iconographic characteristics of the paintings, which date to the XVI and XVII century, but also because they are in the same region and are well preserved and in good condition. Then it is possible to compare their materiality and get new information to answer to some of questions related to these paintings.X-ray Fluorescence (XRF) and Raman spectroscopy were conducted using portable equipment on scaffolds after a global examination under ultraviolet light. We were able to distinguish between different pigments used for different colors such as vermillion, orpiment, and a copper pigment, for the bright red, gold yellow, and green, respectively. These pigments are characteristic of the known Mexican Colonial color palette. Apart from this, we also found the presence of indigo in the blues, minium, and cochineal. A first comparison among the mural paintings of the three sites indicates different palettes and painting periods.

Identification and Analytical Examination of Copper Alloy Pigments Applied as Golden Illuminations on Three Persian Manuscripts

AbstractGolden pigments are among the most common colourants used in Persian illuminated manuscripts. In this research, golden pigments were investigated in three eighteenth- to nineteenth-century manuscripts. Initially, scanning electron microscopy–energy dispersive spectrometry analyses showed that different kinds of metallic pigments were present and some of them were ternary alloys made up of copper, zinc and tin, hence copper-based alloys were ascertained as cheap alternatives to gold. Discolouration of the pigment was observable through alteration of the metallic pigments to greenish residues in the manuscripts. Subsequently, the greenish products in the golden pigments were studied by Raman spectroscopy. Copper carboxylates were recognized as degradation products. We inferred that the alteration is a consequence of the interaction between copper alloy pigments and carboxylic acids in conditions of high humidity. Moreover, more progressive degradation has caused the discolouration, brittleness and gradually crumbling of the paper in the painted areas. Signs of damages in the paper were comparable with decomposition of the paper by green copper pigments such as verdigris in historical documents and miniatures.

Evaluation of Treatments for Stabilization of Verdigris and Malachite Containing Paper Documents

AbstractCopper ions and acids lead to enhanced degradation of the paper carrier. Stabilization treatment of documents with pigments such as verdigris and malachite should therefore include addition of alkalis to combat acid hydrolysis of cellulose and antioxidants to retard oxidative degradation catalysed by copper ions. The paper reviews present approaches for stabilisation of green copper pigments. Furthermore, two recently proposed treatments containing tetraalkylammonium bromide antioxidants and alkali are evaluated. The first treatment is based on interleaving of paper samples containing malachite or verdigris pigments with papers, impregnated with alkaline buffer and antioxidant at elevated relative humidity and applied pressure. The second one is based on the use of non-aqueous suspensions of nano calcium carbonate and/or magnesium oxide particles and tetrabutylammonium or tetrapropylammonium bromide. Size exclusion chromatography is used to monitor the extent of degradation of samples during accelerated ageing, while colour changes of pigments are determined using colourimetry. Results demonstrate that effective stabilization of paper samples can be achieved with tetrabutylammonium bromide and calcium carbonate containing interleaves at 90% RH. When non-aqueous immersion treatment is applied, tetrabutylammonium bromide at a concentration 0.09 M in combination with calcium carbonate nano particles had the most beneficial effect on the paper as well as on the colour of the copper based pigments.

Tribasic copper chloride toxicosis in commercial broiler chicks.

Two broiler chicken houses containing 17,500 chicks each experienced an extreme elevation in chick mortality beginning on day 3 after placement. Clinical signs observed upon farm visit included numerous small chicks for their age; depressed, lethargic, and comatose chicks; and chicks huddling near feed pans and under heaters. Necropsied chicks were markedly pale and had atrophy of the thymus and bursa, swollen and edematous proventriculus, erosions in the koilin and in the proventricular-ventricular junction, pale kidneys, and yellowish to brownish-orange liver often with linear pale areas. The chicks had watery blood and hematocrits measured from 9.5% to 18%. Chicken infectious anemia was initially suspected based on the clinical signs and gross lesions. Histopathology revealed multifocal acute hepatic degeneration and necrosis with golden-brown pigment in the cytoplasm of hepatocytes and Kupffer cells, moderate to severe koilin degeneration and fragmentation, multifocal mild to moderate proventricular necrosis, mild to moderate necrosis and loss of enterocytes, blunting of small intestinal villi, lymphoid depletion in the thymus and bursa, erythrophagocytosis in the liver and spleen, and acute renal tubular degeneration and necrosis. Special stains revealed mild to abundant accumulation of copper pigment in the cytoplasm of hepatocytes and iron pigment in the cytoplasm of Kupffer cells. Feed analysis revealed 2140 to 2393 parts per million of copper in the starter ration, and heavy metal analysis detected markedly elevated copper levels in formalin-fixed samples of the liver. Excessive amounts of tribasic copper chloride in the starter ration caused copper toxicosis in these chicks. Similar clinical signs and lesions were reproduced when the suspect feed was used in an experimental pen trial.

Micro infrared spectroscopy discrimination capability of compounds in complex matrices of thin layers in real sample coatings from artworks

The presence of coating on manufactures either to protect them from the environment, or to give them specific properties—as well as simply to change their aspect—has been shown to be a constant practise throughout history. Their characterization is complex not only because of the inherent variability and diversity of the composition, but also due to the small amount of sample material available. A methodology to study those coatings using microFTIR is proposed. In some cases, the use of microSR-FTIR, which heavily increases spatial resolution particularly appropriate for the analysis of these heterogeneous samples, is also proposed. Data processing tools such as distribution maps of specific infrared bands and curve fitting facilitate the interpretation of the spectra and help identify heavily overlapped spectra. Through the identification of individual bands, it has been possible to discriminate materials and comprehend the interaction processes during aging. Infrared spectra from reference aged materials of known production dates and which are essential in understanding those processes are given. A set of selected case studies including materials of different chemical natures and various historical periods are presented: identification of guanine on the inner coating of a hope chest; determination of a protein glue coating from a gilded Baroque altarpiece; assessment of a beeswax superficial application during the historical restoration of a late 19th century canvas painting; identification of impurities of shellac wax in a shellac coating on a wood moulding from a medieval altarpiece; aging and reaction compounds in Pinus resin, drying oil and green copper pigment mixtures used as colour coatings on Baroque and modern desks.

Coatings with metallic effect pigments for antimicrobial and conductive coating of textiles with electromagnetic shielding properties

Effect pigments were originally developed to realize advanced optical effects by coating on several types of material surfaces. However, metallic effect pigments are expected to be valuable for many other applications, such as antimicrobial effects, electrical conductive coatings, or shielding against radio waves (electromagnetic shielding). Accordingly, the aim of this article is to evaluate the advanced properties which can be realized by application of coatings containing metallic effect pigments onto textile materials leading to new functional textiles. In total, four different metallic effect pigments were investigated and compared to silver and graphite pigments. By application of coatings with copper- or silver-containing effect pigments significant antibacterial properties against E. coli and S. aureus can be realized. To achieve electric conductive textiles, which also enable effective shielding against radio waves, a copper pigment carrying a silver coating leads to the best properties. Altogether, an effective coating method is presented to achieve functional textiles that offer a broad range of possible applications.