Study of degradation processes of metals used in some artworks from the cultural heritage of Andalusia, Spain

Abstract

S St tu ud dy y o of f d de eg gr ra ad da at ti io on n p pr ro oc ce es ss se es s o of f m me et ta al ls s u us se ed d i in n s so om me e a ar rt tw wo or rk ks s f fr ro om m t th he e c cu ul lt tu ur ra al l h he er ri it ta ag ge e o of f A An nd da al lu us si ia a, , S Sp pa ai in n ( (• •) )A. Duran*, **, L.K. Herrera*, M.C. Jiménez de Haro*, J.L. Pérez-Rodríguez* and A. Justo* A Ab bs st tr ra ac ct tThe study of the alteration processes of metals, such as lead, bronze, iron and tin-mercury alloys, used in some of the most important chosen artefacts of Andalusian Cultural Heritage is the main objective of this paper. Hydrocerussite and cerussite were detected in lead seals stored in a hole of cardboard. Bronze is altered to atacamite by environmental contamination, which is also responsible for the formation of rust from iron. Corrosion of the tin-mercury surface of amalgam mirrors produces tin monoxide and tin dioxide and releases liquid mercury from the solid phase. K Ke ey yw wo or rd ds sDegradation processes; Lead; Bronze; Iron; Tin-mercury amalgam.E Es st tu ud di io o d de e l lo os s p pr ro oc ce es so os s d de e d de eg gr ra ad da ac ci ió ón n d de e m me et ta al le es s e em mp pl le ea ad do os s e en n o ob br ra as s d de el l p pa at tr ri im mo on ni io o c cu ul lt tu ur ra al l d de e A An nd da al lu uc cí ía a, , E Es sp pa añ ña a R Re es su um me en n El estudio de los procesos de alteración de metales como plomo, bronce, hierro y aleaciones de estaño-mercurio empleados en algunas de las más importantes ornamentaciones elegidas del patrimonio cultural de Andalucía es el principal objetivo de este trabajo. Hidrocerusita y cerusita se detectaron en sellos de plomo almacenados en compartimentos de cartón. El bronce se altera a atacamita debido a la contaminación ambiental, factor que es también responsable de la formación de compuestos polvorientos a partir del hierro. La corrosión de la amalgama de estaño-mercurio de espejos antiguos produce óxidos de estaño y restos de mercurio líquido procedentes de la fase sólida. P Pa al la ab br ra as s c cl la av ve e Procesos de degradación; Plomo; Bronce; Hierro; Amalgama de estaño y mercurio. 1. . I IN NT TR RO OD DU UC CT TI IO ON NFor millennia, humans have used metals to create both utilitarian and ornamental items. Most metallic items suffer some corrosion process over time, mainly because of oxidation by air. The corrosion products are oxides, hydroxides, sulphides, sulphates and carbonates depending upon the metals present and the environmental condition of the metals.The use of metals for artefact construction has been known since antiquity [1 and 2] . Metals were used less extensively as support for paintings in ancient times, probably because they were highly valued for other purposes and were not available in large sheets or panels. Sheets were beaten out laboriously by hand. Methods for rolling metals were developed in the middle of the 16 th century.Lead alloys were widely used in antiquity, especially in organ pipes, c...

Ceramics from the Alcazar Palace in Seville (Spain) dated between the 11th and 15th centuries: Compositions, technological features and degradation processes

“…The degradation of organic compounds, especially by bacteria activity, leads to the formation of formic acid that reacts with the lead of the glaze, producing the formates. Finally, formates with carbonic acid present in the solution which came into contact with glass transforms lead into cerussite [86]. The bands at 973, 934 and 431 cm −1 may be due to the presence of phosphates [87].…”