Analysis and research of damage phenomena on tin based organ pipes of different ages

Abstract

Organ pipes are made mainly of tin alloys, and they can undergo surface damage usually called ‘sickness of tin’ or ‘tin cancer’. Several parts of degraded organ pipes from organs produced in different periods (from the eighteenth to the twentieth century) and from different areas in Italia were examined and investigated in order to identify the possible causes of damage. Analysis by differential scanning calorimetry-differential thermal analysis (DSC-DTA) measurements was performed to define the crystallographic transformation of the alloys studied as a function of temperature, and a metallographic analysis was done to point out the different microstructural characteristics of the alloys observed. The morphological analysis was improved by a SEM instrument equipped with an energy dispersive device which enables quantitative chemical characterisation of intact and degraded zones to be carried out. The presence of chlorides was identified as responsible for the degradation phenomena, and this conclusion needs to be taken into account in the choice of woods and materials used in restoration.