Publicação

Development of nanomaterials for cultural heritage conservation: evaluation on the degradation state of antique coins by spectroscopic techniques

Ver documento

Detalhes bibliográficos
Resumo:This work is presented in two complementary parts covering the two main fields on the study of cultural heritage. The first one is focussed on the analysis of a set of six dinheiros from the first Portuguese dynasty (13rd and 14th centuries). The coins were analyzed using μ-Energy Dispersive X-ray Fluorescence in order to evaluate their elemental composition, allowing to confirm in four of the coins a billon alloy (copper/silver) and in the remaining two a reduced content of silver. This fact is compatible with the social and economic Portuguese reality during D. Fernando I reign. The coins were further evaluated by means of X-ray Diffraction identifying natives copper and silver, as well as some of their degradation products, such as cuprite, tenorite, malachite, nantokite and atacamite and on the numisms with high silver content, chlorargyrite. By making use of Scanning Electron Microscopy/Energy Dispersive Spectroscopy the morphological analysis on the coins surface was performed evidencing the corroded surface and allowing to identify different morphologies corresponding to copper/copper oxides and silver/silver chloride phases. On the second part, several calcium carbonate (CaCO3) and calcium hydroxide functionalized nanoparticles were synthesized, purified and physicochemical characterized, in order to study their application by dispersion, on manuscripts and its similar for conservation purposes. The effect of different percentages of the functionalizing agent (dodecanoic acid) was investigated. Results from the visual and turbidimetry analyses showed that the dispersions were not stable for the proposed end. By making use of Attenuated Total Reflectance and X-ray Diffraction was possible to conclude that the acid is present on the final CaCO3 product. Scanning Electron Microscopy allowed to prove the morphological changes on the powders particles and made clear the shortage of nano-objects. The followed route is not effective regarding the synthesis of nanoparticles which may justify the instability of the dispersions.
Autores principais:Oliveira, Maria Inês Baião Ramos de
Assunto:Corrosão Moedas Nanopartículas XRF XRD SEM/EDS Turbidimetria ATR Teses de mestrado - 2014
Ano:2014
País:Portugal
Tipo de documento:dissertação de mestrado
Tipo de acesso:acesso aberto
Instituição associada:Universidade de Lisboa
Idioma:inglês
Origem:Repositório da Universidade de Lisboa

Registos relacionados

Registos relacionados