Influence of Formic Acid on Corrosion Behavior of Bronze under Thin Electrolyte Layer

Abstract

The corrosion behavior of formic acid towards bronze under thin electrolyte layer (TEL) was investigated by means of electrochemical measurement. Bare bronze had smaller self-corrosion current density than Cu₂O patina bronze and CuCl patina bronze, while it had higher polarization resistance. The corrosion behavior of bronze materials had differences in various TELs and bulk solutions. The critical thickness of TEL for Bare Bronze was 200 µm, which normly occurred in the transformation from anode control to cathode control. The thickness of TEL had a negligible effect on the corrosion rate of Cu₂O patina bronze when it was greater than 150 µm. For CuCl patina bronze, the corrosion process accelerated with thinner TEL. SEM was used to analyze the morphology and composition of corrosion products. Cu₂O,Cu(OH)(HCOO) and Cu(HCOO)₂ were formed on the surface of Bare Bronze and Cu₂O patina bronze, nevertheless, the main corrosion product of CuCl patina bronze was Cu₂Cl(OH)₃.

Keywords

EIS / bronze / formic acid / atmospheric corrosion

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