Field studies of corrosion behaviour of copper alloys in natural seawater

• Corrosion rates of brasses are similar to those of pure Cu.
• Aluminium in copper alloys significantly reduces corrosion but promotes biofouling.
• Time-varying loading noticeably increases uniform corrosion rate of copper alloys.
• Significant seasonal variation in corrosion rates of copper alloys is observed.

Eight copper alloys were tested in a one-year field deployment in the North Atlantic Ocean. The corrosion behaviour was characterized by weight loss, optical and electronic microscopy analyses. The biofouling performance was quantified in terms of the biomass accumulation. The testing program included specimens in tensioned and untensioned configurations, as well as a set for seasonal deployments. The seasonal corrosion rates were 140% higher, and the rates of tensioned specimens were 39% higher than those of the untensioned specimens after 12 months of deployment. Good biofouling resistance was observed for all but one alloy, which exhibited heavy fouling by barnacles.