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

Abstract

The stress corrosion cracking (SCC) behavior of Al-brass and Cu10Ni alloys was investigated in 3.5% NaCl solution in absence and in presence of different concentrations of Na₂S under open-circuit potentials using the constant slow strain rate technique. The results indicated that the Cu10Ni alloy is more susceptible to stress corrosion cracking than as-received Al-brass at strain rate of 3.5 × 10⁻⁶ s⁻¹ in 3.5% NaCl in presence of high concentration of sulfide ions (1000 ppm). The sulfide ions (up to 500 ppm) has no effect on the stress corrosion cracking of the annealed Al-brass in 3.5% NaCl at two strain rates of 7.4 × 10⁻⁶ and 3.5 × 10⁻⁶ s⁻¹. The results support film rupture for Al-brass and sulfide stress corrosion cracking assisted with pitting corrosion for Cu10Ni at slip steps as the operating mechanisms.