In-situ survey of decaying azulejos panels and the presence of salts

Abstract

Pattern or figurative azulejos are commonly found decorating the interior of churches, palaces and religious buildings in Portugal, representing local productions from the late 16th century onwards. But not every azulejo reached the present day in good condition.. The aim of this research was the survey of in situ forms of degradation, aimed at eventually establishing a relation between the occurrence of soluble salts and decay. Salt samples and small fragments collected in situ were analysed with a scanning electron microscope with microanalysis unit (SEM-EDS) for the identification of saline specimens. NaCl was more abundantly found in near-shore properties, along with trona. Magnesium and calcium sulphate were more common in inland properties.

Keywords

• Azulejos
• Degradation
• Salts