Natural corrosion-induced gold nanoparticles yield purple color of Alhambra palaces decoration.
Sci Adv
; 8(36): eabn2541, 2022 Sep 09.
Article
em En
| MEDLINE
| ID: mdl-36083900
ABSTRACT
Despite its fame as a chemically inert noble metal, gold (alloys) may suffer degradation under specific scenarios. Here, we show evidence of electrochemically corroded gilded tin plasterwork in the Alhambra (Granada, Spain) driving spontaneously made gold nanospheres with the optimal size (ca. 70 nm) to impart purple color at the surface. Purple gold on damaged artworks is found sparsely, and its formation is not fully explained yet. We prove that our decayed gold/silver-tin ornament is due to sequential/coexisting galvanic corrosion, differential aeration corrosion, and dealloying of nonperfectly bonded and defect-based metals. Damage is enhanced by exposure to a chloride-rich atmosphere. A white gypsum coat applied during the 19th century to overlap the unaesthetic gilding assists observation of the gold-based purple color. Our work demonstrates gold dissolution, millimetric migration, physical translocation, and deposition as secondary pure gold nanospheres over a centurial time scale under natural environmental conditions.
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1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Sci Adv
Ano de publicação:
2022
Tipo de documento:
Article
País de afiliação:
Espanha