Evaluation of material condition. Understanding and recognition of corrosion mechanisms underlying. Fundamentals of preventive conservation and treatment methodologies applied to metallic materials. Examples for the most common cultural metallic materials, such as: silver, gold, copper, iron and tin alloys.
Elin Maria Soares de Figueiredo, Rui Jorge Cordeiro Silva
‘Notas para apoio à disciplina de Diagnóstico e Conservação de Metais’, textos elaborados por Rui Silva, 2004. ‘Introdução à Corrosão nos Materiais Metálicos’, textos elaborados por Rui Silva. ‘The elements of Archaelogical Conservation’ J. M. Cronyn, Ed. Routledge, 1990. ‘The Corrosion and Conservation of Metallic Antiquities and Works of Arts’, T. Stambolov, CL publication, 1985. ‘Atlas of Electrochemical Equilibria in Aqueous Solutions’ M. Pourbaix, NACE Int. Cebelcor, 1974. ‘Ancient and Historic Metals. Conservation and Scientific Research’ (Proceedings), ed. D. A. Scott, J. Podany, B. B. Considine, The Getty Conservation Institute, 1991. ‘Principles and Prevention of Corrosion’, Denny A. Jones, Prentice-Hall, 1996 Technical bulletins do CCI, CCI Notes, 9/1 a 9/7 Publicações diversas em Actas de encontros ou revistas científicas da especialidade.
The discipline has weekly theoretical-practical lessons and laboratories.
Transparencies or PowerPoint presentation is used for theoretical classes being the matter exposed in a class room when required.
Laboratorial classes are related to the experiences demonstration of the concepts already given in theoretical sessions. For demonstration purposes visits to museums and conservation labs are effectuated.
The evaluation is obtained through two tests for the students that obtained frequency by being assisting at labs and presenting the respective reports.
The students with a grade in the test, equal or superior to 9.5 (ranking of 20) have exemption from final exam.
The final classification will be a weighted average of the final exam grade or test grade (50%) plus lab reports (50%). To take into account the final exam grade or the test grade should be at least 9.5 in a ranking of 20.
Introduction to materials diagnosis. Categories of object condition or conservation priority.
Corrosion. Atmospheric corrosion (characterization of atmospheric types in term of it relative humidity and pollutants agents). Archaeological objects: basics of corrosion in soils and sea waters.
Conservation. Concepts of cleaning and stabilization, consolidation and reparation, protection and storing of metallic objects. Protective coatings (waxes and lacquers), storage boxes and bags, pollutants and oxygen absorber products and vapor phase inhibitors used in conservation of metallic objects.
Silver and silver alloys
Corrosion under aerobic conditions (clean and pollutant atmospheres with sulfur sources). The tarnishing of silver objects. Corrosion in aqueous solutions containing chlorides and in other more complex environments, such sea waters and soils. Corrosion under anaerobic conditions and in the presence of sulfur reducing bacteria (SRB’s). Appearance of decayed silver objects.
Conservation and intervention; care and cleaning, silver tarnish removal and removal of thick and hard corrosion products.
Copper and copper alloys
Iron and Iron alloys
Corrosion under aerobic conditions (clean and pollutant atmospheres with carbonate, sulphate and cloride sources). Corrosion in liquids. Corrosion of copper under anaerobic conditions (environment containing chlorides or sulphides). The Bronze disease. Examples. Appearance of decayed copper rich objects.
Conservation: removal of green copper products and stabilization of copper objects contaminated with chlorides. Use of inhibitors and protective coatings.
Tin And Tin alloys.
Corrosion under aerobic conditions (clean and pollutant atmospheres with carbonate, sulphate and chloride sources). Corrosion in liquids. Corrosion under anaerobic conditions and in the presence of sulfur reducing bacteria (SRB’s). The “Iron sweating” and the formation of “green rusts”. Examples. Appearance of decayed forged iron, cast iron and steels objects.
Conservation of objects with high chloride concentration (mechanical or electrolytic cleaning, chemical extraction, electrolytic and chemical reduction, Rust removal products. Protective coatings and passivation procedures.
Other metals and Alloys
Corrosion under aerobic conditions (clean and pollutant with chlorides). Surface oxides and deterioration mechanisms. The “tin pest”. Corrosion in liquids. Appearance of decayed pewter objects.
Conservation of tin objects: cleaning, stabilization and coating.
Programs where the course is taught: