Laboratory and field tests on patinas and protective coating systems for outdoor bronze monuments

Six protective coating systems, commonly used in conservation practice, have been tested both on polished bronze coupons and on selected areas of a bronze statue in similar exposure conditions. Patinas have been characterised both on outdoor exposure on the monument and as developed on the polished bronze coupons. Electrochemical Impedance Spectroscopy measurements, using a specially designed contact probe, have been conducted on coupons and in situ on the bronze statue. Data for the first two years of weathering in a marine environment are reported. The coating performance on the polished coupons and on the corroded bronze monument is discussed.