Surface and Bulk Investigations of Organ Metal Pipe Degradation

In literature the most studied organ degradation processes are related to instruments located in Northen Europe where the ageing of metal alloys is influenced by the environment and the climate typical of those regions. This paper focuses on some examples of degraded organ pipes coming from several parts of Sicily (the biggest island of the Mediterranean Sea) characterized by different environmental and climate conditions typical for the Mediterranean area. Investigation on the specific causes that had produced the degradation was performed by using X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy coupled with Energy-Dispersive X-ray analysis, (SEM-EDX) and X-Ray Diffraction (XRD). Three different kinds of degradations were found: the formation of tin dioxide blisters on the tin based pipes caused by normal oxidation processes induced by the atmospheric oxygen; another tin oxidation process results in tin chloride phases formation; finally, in the case of lead pipes, the degradation is related to the formation of lead nitrate salts.