Protective silane treatment for patinated bronze exposed to simulated natural environments

The protective efficiency of 3-mercapto-propyl-trimethoxy-silane (PropS-SH) was evaluated towards bare and aged bronze. The wet & dry (stagnant rain) and dropping (runoff) techniques were used both for producing pre-patinated surfaces representative of real artefacts and for performing accelerated tests to verify PropS-SH protection efficiency. The surface corrosion products and the metal release were analyzed through spectroscopic techniques. The role of alloying metals in the corrosion/inhibition process was assessed through electrochemical analyses performed on bare and prefilmed alloying elements. The results showed good protective efficiency of the silane coating on bare and pre-patinated samples, both in stagnant and runoff conditions.