Effect of sulfide ions on the corrosion behaviour of Al–brass and Cu10Ni alloys in salt water

The corrosion behaviour of modified Al–brass (MA72) and Cu10Ni alloys was investigated in 3.5% NaCl in absence and presence of different concentrations of sulfide ions. The results indicated that the Cu10Ni alloy demonstrated better corrosion resistance in 3.5% NaCl solution. The corrosion of the alloys has increased in presence of sulfide ions. The increase of sulfide ions (500, and 1000 ppm) resulted a pitting corrosion in case of Cu10Ni and intergranular corrosion of Al–brass. The detrimental effect of sulfide on the corrosion resistance increases with the increase of sulfide ion concentrations. The results of the weight variations and potentiostatic polarization are in agreement with the potential–time measurements that the sulfide ions in polluted seawater promotes the corrosion of Cu10Ni than Al–brass. The formation of Cu2S interferes with the protecting oxide film and reduces its corrosion resistance.