Influence of microstructure and composition on corrosion of lead-rich organ pipes

Publisher Summary This chapter discusses influence of microstructure and composition on corrosion of lead-rich organ pipes. It reports the results of chemical and micro-structural investigations on samples from (1) the organ in the Basilica di Collemaggio (L'Aquila, Italy), selected as a reference organ affected by corrosion and (2) the organ in the Church of Madonna di Campagna (Ponte in Valtellina, Italy), selected as a reference for a healthy situation. The results of the characterization of the samples taken from corroded pipes indicate that lead carbonates are the main corrosion products that form on the inner surface of the foot of the pipes. Samples from reference organs with a high concentration of organic acids in the environment (e.g. L'Aquila) are extensively corroded. One of the key material factors in influencing the corrosion behavior of the pipes appears to be the tin content in the alloy and also copper traces seem to play a significant role. Further work is needed to evaluate the influence of tin and copper content on corrosion.