Relatório de estágio realizado na Direcção Regional de Cultura de Lisboa e Vale do Tejo

O relatório de conclusão de Mestrado Integrado em Gestão e Valorização do Património Histórico e Cultural aqui apresentado tem como principal objectivo a descrição e análise das várias actividades realizadas na Direcção Regional de Cultura de Lisboa e Vale do Tejo. Cada actividade descrita neste relatório, esta ligada a diferentes áreas de actuação da Direcção Regional de Cultura de Lisboa e Vale do Tejo. Todos eles foram realizados por mim durante os sete meses de estágio. As várias actividades estão divididas em três pontos: estudo, classificação e reabilitação do património. Este relatório tem inicialmente uma análise sobre gestão e valorização do património, procurando contextualizar as várias actividades desempenhadas durante o estágio. Essa analise mostra a evolução do conceito de património e as apolíticas para a sua protecção e valorização, destacando o contributo do património na evolução económica e cultural dos centros urbanos. ABSTRACT; Report done for the Master Degree in Management and Valorisation of Cultural and Historic Heritage. The report main purpose is to describe and to analyse the internship activities in the Regional Direction of Culture of Lisbon and Tagus Valley, carried out in seven months. The report is structure in three main points: study, classification, and heritage rehabilitation. Begins with the history of the heritage concept since the beginning of the 20th century and follows with the study of the evolution of the protection and valorization politics in Portugal, standing out the contribution of the heritage in the economic and cultural improvement in urban centres. Contextualization of the several activities performed in the internship.

Development and optimisation of protocols for surface cleaning of cultural heritage metals

The conservation and valorisation of cultural heritage is of fundamental importance for our society, since it is witness to the legacies of human societies. In the case of metallic artefacts, because corrosion is a never-ending problem, the correct strategies for their cleaning and preservation must be chosen. Thus, the aim of this project was the development of protocols for cleaning archaeological copper artefacts by laser and plasma cleaning, since they allow the treatment of artefacts in a controlled and selective manner. Additionally, electrochemical characterisation of the artificial patinas was performed in order to obtain information on the protective properties of the corrosion layers. Reference copper samples with different artificial corrosion layers were used to evaluate the tested parameters. Laser cleaning tests resulted in partial removal of the corrosion products, but the lasermaterial interactions resulted in melting of the desired corrosion layers. The main obstacle for this process is that the materials that must be preserved show lower ablation thresholds than the undesired layers, which makes the proper elimination of dangerous corrosion products very difficult without damaging the artefacts. Different protocols should be developed for different patinas, and real artefacts should be characterised previous to any treatment to determine the best course of action. Low pressure hydrogen plasma cleaning treatments were performed on two kinds of patinas. In both cases the corrosion layers were partially removed. The total removal of the undesired corrosion products can probably be achieved by increasing the treatment time or applied power, or increasing the hydrogen pressure. Since the process is non-invasive and does not modify the bulk material, modifying the cleaning parameters is easy. EIS measurements show that, for the artificial patinas, the impedance increases while the patina is growing on the surface and then drops, probably due to diffusion reactions and a slow dissolution of copper. It appears from these results that the dissolution of copper is heavily influenced by diffusion phenomena and the corrosion product film porosity. Both techniques show good results for cleaning, as long as the proper parameters are used. These depend on the nature of the artefact and the corrosion layers that are found on its surface.