Selection of bronze alloys with reduced lead content suitable for outdoor sculptures production

In the present work bronze alloys with a new chemical composition and suitable for the outdoor sculptures production have been developed. The effect of different elements as Ni, Bi and Si on the corrosion resistance of bronze alloys has been investigated. A particular effort has been made to obtain materials with an advanced resistance toward corrosion and also having a reduced content of lead. The behaviour toward corrosion has been investigated by linear polarization resistance measurements (LPR) and electrochemical impedance spectroscopy (EIS). The material characterization has been carried out by SEM-EDS measurements. An artificial K2S patina has been produced on materials in order to obtain a surface similar to that of artworks for outdoor exposures. The results arising from the LPR and EIS techniques have been comparatively evaluated in order to select the bronze alloys showing the best corrosion resistance. The results indicate that the presence of Ni and Si along with a reduced Pb content improves the anticorrosive characteristics of the alloys while the absence of Pb makes the material performances worse.