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

摘要

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 po-tentiostatic 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 Cu_2S interferes with the protecting oxide film and reduces its corrosion resistance.