A field testing of corrosion and biofouling behavior of eight copper alloys was carried out at the Portsmouth Harbor, USA (North Atlantic Ocean). The plate specimens of the alloys were submerged for one year to investigate the effect of seawater exposure on corrosion and accumulation of biofouling. The specimens were divided into two sets to evaluate the effect of intermittent corrosion layer removal (three-month periods) vs. continuous exposure with undisrupted surface layer. Corrosion behavior was characterized as uniform corrosion rates through weight measurements, and as localized corrosion attack through analysis of cross-sections. Biofouling behavior was quantified in terms of the biomass accumulation.
It was found that the corrosion rates of the specimens with intermittent removal of corrosion layer were approximately 2.4 times higher than those with intact surface. The biofouling resistance of eight alloys was found to be excellent: less than 0.5% of weight increase over the whole exposure period. However, one of the alloys demonstrated poor resistance (40% increase in weight).
