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[EN] This is the experimental dataset used in the paper: Protective coatings on metals found in scientific-technical collections: the collection of the Spanish National Museum of Science and Technology (MUNCYT). This data presents results on the protective properties of different coatings over metals -bare brass and steel- representative of those found in scientific-technical heritage collections. After a previous examination of several objects to characterise the metals and alloys in the collection of the Spanish National Museum of Science and Technology (MUNCYT), an evaluation of protective coatings has been done. Specifically, Paraloid B-44, B-48, B-67, B-72, Incralac, Cosmolloid H80, double layer of B-72+H80 and shellac have been studied to make a first screening in order to select the most promising candidates for each case and determine the most appropriate methodology and key factors for the study. Coatings have been applied on clean metal surfaces and aged up to 336 hours, by cycles of UV light and water condensation at elevated temperatures. Changes in the aspect of the coupons has been assessed by visual examination, optical microscopy and colorimetric measurements. EIS has been used for a quantitative evaluation of the protective properties and FTIR to measure chemical changes of the layers, allowing to follow, understand and compare the behaviour of the different coatings and substrates upon artificial ageing., [ES] Este es el conjunto de datos experimentales utilizado en el artículo: Recubrimientos protectores sobre metales encontrados en colecciones científico-técnicas: la colección del Museo Nacional de Ciencia y Tecnología de España (MUNCYT). Estos datos presentan resultados sobre las propiedades protectoras de diferentes recubrimientos sobre metales -bronce y acero- representativos de los encontrados en colecciones de patrimonio científico-técnico. Tras un examen previo de varios objetos para caracterizar los metales y aleaciones de la colección del Museo Nacional de Ciencia y Tecnología (MUNCYT), se ha realizado una evaluación de los recubrimientos protectores. En concreto, se han estudiado Paraloid B-44, B-48, B-67, B-72, Incralac, Cosmolloid H80, doble capa de B-72+H80 y goma laca para realizar una primera criba con el fin de seleccionar los candidatos más prometedores para cada caso y determinar la metodología y factores clave más adecuados para el estudio. Los recubrimientos se han aplicado sobre superficies metálicas limpias y se han envejecido hasta 336 horas, mediante ciclos de luz UV y condensación de agua a temperaturas elevadas. Los cambios de aspecto de los cupones se han evaluado mediante examen visual, microscopía óptica y mediciones colorimétricas. Se ha utilizado EIS para una evaluación cuantitativa de las propiedades protectoras y FTIR para medir los cambios químicos de las capas, lo que ha permitido seguir, comprender y comparar el comportamiento de los diferentes recubrimientos y sustratos tras el envejecimiento artificial.

[EN] This is the experimental dataset used in the paper: Testing protective coatings for metal conservation: the influence of the application method. This data presents results on the effect that methodology application variables can have on the protective capacity of the coatings. The influence of the thickness, number of layers and drying time of Paraloid B72, C80 microcrystalline wax and Incralac on bare steel coupons on the performance of the coatings has been evaluated with techniques such as: electrochemical impedance spectroscopy (EIS), a reflected light metallurgical microscope and electromagnetic induction thickness probe. It has been shown that the number of layers is not always proportional to the thickness of the coating and that after accelerated ageing, some coatings that had been left to dry for 14 days, have a better protective capacity than those that were left to dry for less time., [ES] Este es el conjunto de datos experimentales utilizado en el artículo: Pruebas de recubrimientos protectores para la conservación de metales: la influencia del método de aplicación. Estos datos presentan resultados sobre el efecto que las variables de aplicación de la metodología pueden tener en la capacidad protectora de los recubrimientos. Se ha evaluado la influencia del espesor, número de capas y tiempo de secado de Paraloid B72, cera microcristalina C80 e Incralac sobre cupones de acero desnudo en el comportamiento de los recubrimientos mediante técnicas como: espectroscopia de impedancia electroquímica (EIS), microscopio metalúrgico de luz reflejada y sonda de espesores por inducción electromagnética. Se ha demostrado que el número de capas no siempre es proporcional al espesor del recubrimiento y que, tras un envejecimiento acelerado, algunos recubrimientos que se habían dejado secar durante 14 días, tienen una mejor capacidad protectora que los que se dejaron secar durante menos tiempo.

Materials such as wood, textiles, or plastics that are part of the exhibition system in museums are known to emit pollutants such as organic acids. Scientific and technical objects that include these materials in their composition can themselves be a potential source of emissions, which, together with inappropriate humidity and temperature conditions, can lead to corrosion of the metallic parts. In this work, we have studied the corrosivity of different locations in two venues of the Spanish National Museum of Science and Technology (MUNCYT). Coupons of the most representative metals from the collection were placed in different showcases and rooms for 9 months. The corrosion of the coupons has been evaluated in terms of the rate of mass gain, colour changes and characterisation of the corrosion products. The results were correlated to the relative humidity and concentration of gaseous pollutants to determine which metals are most susceptible to corrosion. The results show that metal artefacts exposed in showcases have a higher risk of corrosion than those exposed directly in the room, and that some pollutants are emitted by the artefacts. The corrosivity of the museum environment is low for copper, brass, and aluminium in most locations; however, some placements present a higher aggressivity for steel and lead, due to the high humidity and the presence of organic acids.

This paper presents results on the protective properties of different coatings over metals representative of those found in scientific–technical heritage collections. An examination of several objects in the collection of the Spanish National Museum of Science and Technology have allowed the identification of brass and steel as the most representative metals, and the existence of coatings (mainly shellac and acrylic resins) applied for aesthetic and/or conservation purposes. Based on these findings, brass and steel coupons coated with Paraloid B-44, B-48, B-67, B-72, Incralac, Cosmolloid H80, B-72 + H80 double layer and shellac have been studied to carry out a first screening in order to select the most promising candidates and determine the most appropriate methodology and key factors for the study. Coatings have been aged up to 336 h using cycles of UV light and water condensation. The change in the aspect of the coupons has been assessed via visual examination, optical microscopy and colorimetric measurements, with B-44 and Incralac showing the least change. EIS has been used for a quantitative evaluation of the protective properties and FTIR to measure chemical changes experienced by some coatings, such as B-48 and B-67. These evaluations allowed us to follow, understand and compare the behaviour of the different coatings and substrates after artificial ageing.

Colour changes of cultural heritage objects can be related with degradation of materials, thus a proper colour monitoring system can be used to detect conservation problems. With this purpose, a monitoring methodology for cultural heritage preventive conservation based on tailored colour reference charts and image analysis is proposed. Reference colour charts have been designed and tested for use in museums. Charts containing 64 colour patches have been printed using high-stability inks on 4 different substrates: Acid-free paper SkyLight, Acid-free paper covered with a propylene film, FOREX® and GlassPack. The stability has been studied by accelerated ageing in an UV chamber, and the harmlessness of the materials by Oddy Test. The final selection of material, laminated paper, is a balance between the colour change upon ageing and the performance in the Oddy Test. Using this material and the proposed design, colour change of copper and silver coupons has been assessed using images that are adjusted and calibrated by an adaptive calibration framework employing a given set of reference colours which homogenises the visual information in the supplied images. Thus, regardless of the camera of origin, any processed picture will deliver reliable information of the state of the colour in the metal surfaces at the moment it was taken. Results demonstrate the adequacy of the approach and the design for colour calibration, so these charts can be used to monitor colour change of sensitive materials ¿metal coupons¿ using photographs. As colour change of reference metals is a consequence of corrosion by environmental factors this may be used as a measure of air quality in museum environments. This methodology can be used to design a low-cost preventive conservation tool, where colour change of metal coupons ¿or other reference materials¿ can be followed through image analysis of pictures taken periodically by conservators or visitors, introducing citizen science in the conservati

The main component of the cement hydration, are both, the calcium silicate hydrate (C–S–H) and calcium silicate hydrate with Al (C–S(A)–H), whose composition is characterized by its calcium to silicon ratio (Ca/Si), which normally varies from 0.6 to 1.6. The theoretical Ca/Si ratios of the synthesized gels were compared with those of the experimental gels, which were determined by inductively coupled plasma atomic emission spectroscopy (ICP-OES). In addition, the microstructure of the gels was studied by spectroscopic techniques: infrared and Raman spectroscopy and nuclear magnetic resonance. By the double-decomposition method used in this work (1 day at 25 °C, inert atmosphere and pH = 12.3), only C–S–H and C–S(A)–H gels with a maximum Ca/Si ratio ranging from 0.8 to 1.0 were synthesized. However, the structures of the gels are slightly different as the Ca/Si ratio increases. [Figure not available: see fulltext.].