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Título del libro: Eurocorr 2017 - The Annual Congress Of The European Federation Of Corrosion, 20th International Corrosion Congress And Process Safety Congress 2017
Título del capítulo: Identification of the silver tarnish layer constituents by cathodic reduction

Autores UNAM:
FRANCISCO JAVIER RODRIGUEZ GOMEZ;
Autores externos:

Idioma:
Inglés
Año de publicación:
2017
Palabras clave:

Binary alloys; Conservation; Copper alloys; Corrosion; Reduction; Scanning electron microscopy; Silver; Silver compounds; Sulfur compounds; Cathodic reductions; Chemical compositions; Chronopotentiometry; Conservation areas; Corrosion products; Surface conditions; Tarnish; Uniform distribution; Silver alloys


Resumen:

The corrosion layer of ancient objects made with silver alloys have the same color and appearance with independence of the chemical composition. This layer depends on the environment those objects were exposed. Sulphide is the most aggressive pollutant to Ag-Cu alloys. The most common silver alloys that were used to make the ancient objects were 0.925, 0.800 and 0.720. In conservation area is important to know the composition of corrosion layer to restore the heritage objects. The aim of this study was to identify the corrosion products exposed in an environment with sulphides by electrochemical cathodic reduction and scanning electron microscopy. Ag2S and Cu2S could be identified as the main compounds of tarnishing. The SEM-EDS analysis showed an uniform distribution of Cu over the surface of the samples and a smoother surface condition as the Cu concentration increased in the alloy. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. All rights reserved.


Entidades citadas de la UNAM: