5 results on '"Brambilla, Laura"'
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2. The Cleaning of Corroded Lacquered Brass with Complexing Agents: A Comparative Study.
- Author
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Schröter, Julie, Truffa Giachet, Miriam, Cuvillier, Luana, Joseph, Edith, and Brambilla, Laura
- Subjects
BRASS ,ETHYLENEDIAMINETETRAACETIC acid ,SURFACE cleaning ,COMPARATIVE studies ,CLEANING - Abstract
Lacquered brass objects are widely present in scientific and technical heritage collections. Localized atmospheric corrosion occurs on the metal when the coating fails to play its protective role. Although lacquered brass objects are not necessarily endangered by this phenomenon, the presence of dark, unpleasant corrosion spots alters the surface appearance, affecting the readability of the objects. Conservators are therefore frequently asked to clean these surfaces. We hereby present the results of a study conducted in the framework of the CleanLaB (Cleaning of Lacquered Brass) project at the Haute Ecole Arc of Neuchâtel for the cleaning of lacquered brass. This work investigates the effects of several gelled cleaning systems applied on artificially aged, lacquered brass samples to remove the corrosion products without affecting the integrity of the coating. The performance of complexing agents commonly used in conservation was compared on lacquered brass mock-ups coated with shellac resin by means of multiple non-invasive characterization and imaging techniques. The tests included conventional complexing agents like sodium citrate and disodium ethylenediaminetetraacetic acid, as well as a bio-originated system based on deferoxamine, a microbial metal chelator investigated as a green alternative in cleaning formulations. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. Degradation of heritage cans: Monitoring of museums’ collections.
- Author
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Brambilla, Laura, Cova Caiazzo, Fabio, Michel, Aline, Mischler, Stefano, and Bertholon, Régis
- Subjects
- *
COLLECTION management (Museums) , *WORLD Heritage Sites , *DETERIORATION of materials , *TINPLATE , *CORROSION & anti-corrosives , *CONSERVATION & restoration - Abstract
This paper presents the outcomes of the CANS project (Conservation of cAns in collectioNS), an interdisciplinary research aiming at proposing conservation strategies for full cans, still retaining their original contents, in museums and collections. The paper includes the results of the condition report, measuring the state of conservation of 150 cans from 5 Swiss collections, the correlation between state of conservation, content and age of the can and the extensive characterization of the cans’ materials for a better understanding of the corrosion mechanisms. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
4. Setup of Galvanic Sensors for the Monitoring of Gilded Bronzes.
- Author
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Goidanich, Sara, Gulotta, Davide, Brambilla, Laura, Beltrami, Ruben, Fermo, Paola, and Toniolo, Lucia
- Subjects
ELECTROCHEMICAL sensors ,CORROSION & anti-corrosives ,CONSERVATION & restoration ,BRONZING ,DETECTORS - Abstract
Traditional electrochemical techniques, such as linear polarization resistance (Rp), and electrochemical impedance spectroscopy (EIS), cannot be applied to gilded bronzes, as it may not be possible to interpret the results obtained due to the bimetallic nature of the studied material. The measurement of the macrocouple current generated by the gold/bronze galvanic couple can be used as an indicator of degradation processes. Nevertheless, this measurement cannot be performed directly on the original artifacts due to the systematic presence of short-circuits between the two metals. In the present work the use of galvanic sensors is proposed as a possible solution for the monitoring of gilded bronze artefacts. The sensors have been designed to simulate real gilded bronze surfaces in terms of composition and stratigraphy and have proved to be a reliable diagnostic tool for the in situ monitoring of the rates of deterioration of gilded bronze surfaces and to test new conservation treatments. Their set-up and application is reported and their performances discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
5. Corrosion mechanisms and durability models for historical tinplate food cans
- Author
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Cova Caiazzo, Fabio, Mischler, Stefano, and Brambilla, Laura
- Subjects
Corrosion ,Food packaging ,Tinplate ,Tin-iron galvanic coupling ,Tin ,Modelling - Abstract
Since the early of the 19th century, canning is one the most efficient ways to preserve foods. Tinplated steel has been used since the beginning for this purpose and it is still one of the most used materials for cans production because it combines the good mechanical strength of steel with the corrosion resistance of tin. Nowadays, historically relevant cans enrich the collections of several museums around the world. However, these collections are threatened by severe corrosion phenomena, which may lead to perforation, swelling and bursting of the container. The aim of this thesis is to study the corrosion mechanism of tinplate and to propose a long-term durability model that can be used by museums conservators in order to define an intervention timeline for historical and new cans collections. The strategy of the thesis has been to investigate separately the material structure and the corrosion mechanisms of the tinplate constituents in model electrolytes and then to combine the two outcomes in a predictive model. Tinplate is a composite material constituted by several metallic layers, which interacts with the complex food matrix. The sandwich like structure of tinplate, constituted by an external tin layer, an intermediate intermetallic compound layer and a core of mild steel, was characterized via a multi-technique approach combining chrono-potentiometry, chrono-amperometry, Auger Electron Spectroscopy, X-ray Fluorescence Spectroscopy, Scanning Electron Microscopy and 3D White Light Interferometry. The analysis pointed out that the relevant features that need to be considered in order to make predictions on the corrosion mechanism and lifetime of tinplate are the thickness of the tin layer, its porosity, the base steel roughness and the structure of the tin-steel interface. Canned foods cover a wide range of pH, from neutrality to pH 3 and they contain several molecules and ions known to impact tinplate corrosion, such as polyprotic complexing acids, protons, oxygen, nitrates, sulphur dioxide, natural dyes etc. The mechanisms and the kinetics of tin corrosion and tin-iron galvanic coupling were investigated in model electrolytes constituted by buffer solutions of citric, malic and oxalic acids at constant oxygen concentration, mimicking the typical environment of canned fruits and vegetables. The study was carried out by means of an electrochemical approach based on potentiodynamic polarization technique in static conditions and under convection (Rotating Disk Electrode). X-ray Photoelectron Spectroscopy was used as additional technique for the investigation of the tin-iron galvanic coupling mechanism. The results showed that, depending on the potential, different mechanisms control tin corrosion: charge transfer reduction of protons, diffusion-limited reduction of oxygen, active dissolution of tin and its passivation. Interestingly, all these reaction are affected by parameters such as pH, oxygen content and complexing strength of electrolytes but to a different extent. Furthermore, the study of tin-iron galvanic coupling has shown an increase of the kinetic of tin dissolution but at the same time, a reduction of the reactivity of iron towards acid corrosion due to of a self-healing mechanism. The rationalization of the corrosion mechanisms through kinetic equations depending by well-defined parameters has allowed to develop a durability model able to predict the lifetime of tinplated cans based on the material structure.
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