ABSTRACT
Politecnico di Milano, Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, via Mancinelli 7, 20131 Milano, Italy
Abstract. This paper describes the preliminary results of a research aimed at the evaluation of the conservation of the capitals of the Romanic ciborium of San Pietro al Monte Abbey in Civate. In situ visual inspection has shown serious decay induced by the corrosion of steel inserts embedded in the capitals. Indeed steel corrosion has induced cracks in some areas of the capitals and hence it has caused the detachment of mortar fragments. Mortars and metallic samples have been collected and analysed by different techniques (OM, SEM-EDS, XRD, TGA-DTA, OES and acid attack). These investigations have shown the capitals inner arrangement: a mortar multilayer structure, reinforced by different metallic elements. Mortars are made either of magnesic lime binders, or gypsum and lime binders. Metallic inserts are made of low-carbon steel, characterised by perlitic and ferritic microstructure, by now oxidised in many thick layers which have been characterised.
