Metal sarcophagi of the Habsburg Imperial Crypt, Church of the Capuchin Friars, in Vienna, Austria: Analysis of surface coatings

Abstract

The Imperial Crypt below the Capuchin church in Vienna (the Kapuzinergruft) has been the principal burial site for the Habsburg dynasty since 1633. Today it holds a world-famous ensemble of sarcophagi and is one of the most important sites in Austria. Due to unfavourable climatic conditions in the crypt, until recently the tin-alloy cast-metal sarcophagi were affected by serious corrosion processes. Several restoration campaigns were undertaken between 1964 and 2002, when many of the sarcophagi were treated with various protective coatings. However, after these interventions a new problem arose: ensuing damage occurred in areas where the protective coatings were applied. Information about the chemical composition of the multi-layered coating systems and their influence on the metal surfaces thus became a crucial area for research. This paper presents the latest results of the technical examination of the surface coatings from three tin-alloy sarcophagi.

Keywords:

• Tin-alloy Sarcophagi
• Tin corrosion
• Protective coatings
• Synthetic Resins
• SEM–EDX
• XRD
• μ-FTIR
• GC–MS

Acknowledgements

The authors would like to thank Father Gottfried from the Order of Capuchins together with Dr Barbara Neubauer from the Austrian Federal Office for the Care of Monuments in Vienna for allowing sampling. The authors wish to acknowledge all colleagues involved in this project without whom this research would not have been completed, specifically Mag Elisabeth Hösl, Germany, for her comprehensive review study; Dr Milan Vlček, the University of Pardubice, CZ, for SEM-EDX; Dr Miroslava Novotná, the Institute of Chemical Technology Prague, CZ, for μ-FTIR; Dr Petr Bezdička, Institute of Inorganic Chemistry, the Academy of Sciences of the Czech Republic in Řež, CZ, for XRD; and Dr Jiří Děd, the Institute of Chemical Technology Prague, CZ, for consultation on metal corrosion. The authors are grateful to the Austrian Science Fund (FWF) for funding this project no. L187–N11.

Materials and suppliers

Toluene, methanol: Sigma-Aldrich (www.sigmaaldrich.com).

Meth-Prep II: Alltech Associates (www.alltechWEB.com).