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[EN] The application of solid state electrochemistry techniques for the characterization and dating of leaded bronze objects is described. Characteristic voltammetric signatures of copper and lead corrosion products were used as markers of more or less prolonged corrosion periods. The proposed methodology was applied to samples from the Roman archaeological sites of Valeria (Spain) and Gadara (Jordan), Roman and medieval sites in Xativa (Spain), and modern statuary exhibited outdoors, on the campus of the Universitat Politecnica of Valencia, Spain, covering a time interval between the fourth to second century bc and the 20th century ad. For such samples, the ratio between the signals for copper and lead corrosion products decreased monotonically with the corrosion time. This variation was modelled on the basis of thermochemical and kinetic considerations, the experimental data being consistent with a potential rate law for the corrosion process., Financial support from the MINECO Projects CTQ2014-53736-C3-1-P and CTQ2014-53736-C3-2-P, which are supported by ERDF funds, is gratefully acknowledged. We wish to thank the Fondo de Arte y Patrimonio of the Universitat Politecnica de Valencia; the Museu de Prehistoria of Valencia, and its director Helena Bonet and curator Jaime Vives-Ferrandiz; and the Museu Municipal of Xativa and its director Angel Velasco. We also wish to thank Dr Jose Luis Moya Lopez and Mr Manuel Planes Insausti (Microscopy Service of the Universitat Politecnica de Valencia) for technical support.

El examen científico de obras de arte y materiales arqueológicos se ve dificultado por el requisito de preservar la integridad del objeto en la medida de lo posible. Por ello, es conveniente utilizar técnicas de análisis no destructivas o mínimamente destructivas. En el caso de objetos metálicos, este requisito normalmente impide la toma de muestra del sustrato metálico, por lo que es necesario llevar a cabo los análisis en sus capas de corrosión. El presente trabajo consiste en el estudio analítico de objetos escultóricos y arqueológicos compuestos de aleaciones de cobre a partir de sus capas de corrosión. El estudio se basa, fundamentalmente, en el análisis mediante voltamperometría de micropartículas inmovilizadas (VIMP), una técnica que proporciona respuestas específicas para especies electroactivas en sustratos sólidos con gran sensibilidad. Los resultados voltamperométricos, complementados con los obtenidos mediante otras técnicas de análisis (ATR-FTIR, FESEM-EDX, SECM), permiten la identificación de productos de corrosión de cobre y plomo. Para explicar la influencia mutua de estos productos de corrosión en las respuestas voltamperométricas se propone un modelo teórico basado en caídas óhmicas no compensadas involucradas en los procesos electroquímicos. Por su parte, la técnica de espectroscopia de impedancia electroquímica (EIS) aporta mayor información sobre los procesos de corrosión y las características de porosidad y permeabilidad de superficies metálicas, permitiendo un agrupamiento de las muestras en función de sus diferentes procedencias y procesos de elaboración. Con la finalidad de combinar las capacidades de la EIS con las ventajas que ofrece la VIMP, se presenta una intersección entre ambas metodologías. Este nuevo método consiste en la realización de medidas de impedancia sobre depósitos microparticulados de patrones y muestras inmovilizados sobre electrodos de grafito. Finalmente, se presenta una ley de velocidad basada en consideraciones termoquímicas y cinéticas, a partir de la cual se ha diseñado un método de datación de muestras arqueológicas de bronce plomado. Del mismo modo, también se proponen criterios de autentificación de muestras arqueológicas sobre la base de las respuestas voltamperométricas de los productos de corrosión de cobre y plomo. Scientific examination of artworks and archaeological pieces is hampered by the requirement to preserve the integrity of the objects as far as possible. Thus, it is necessary to employ non-destructive or minimally destructive analytical techniques. In the case of metallic objects, this requirement usually prevents the sampling on the metallic substrate, so the analysis must be carried out in the corrosion layers. In the present work an analytical study of sculptural and archaeological objects made by copper alloys through their corrosion layers has been carried out. The study is based primarily on analysis of voltammetry of immobilized microparticles (VIMP) analysis, a technique that provides specific responses for electroactive species from solid substrate. Voltammetric data, supported by other analysis techniques (ATR-FT-IR, FESEM-EDX, SECM), allowed to identify copper and lead corrosion products. In order to explain the mutual influence of these corrosion products on the voltammetric responses, a theoretical model based on uncompensated ohmic drops involved in the electrochemical processes has been proposed. On the other hand, the electrochemical impedance spectroscopy (EIS) technique provides interesting information about corrosion processes and textural properties (porosity, permeability) of the metallic surfaces, able to be used to group the samples in order to establish provenances and manufacturing methods. In order to combine the advantages of EIS with the capabilities of VIMP, an intersection between both methodologies has been presented. This new method consists in carrying out impedance measurements of microparticulate deposits of reference materials and samples attached to graphite electrodes in contact with an aqueous electrolyte. Finally, a potential rate law for the corrosion processes based on thermochemical and kinetics aspects is presented. On the basis of this law, a dating method of archaeological samples of leaded bronze has been designed. In the same way, new diagnostic criteria for authentication of archaological leaded bronze objects are also proposed, based on voltammetric features for lead and copper corrosion products.