Establishing a pre-passivation method to improve the corrosion resistance of B30 alloy in deep-sea environment

The response surface methodology (RSM) was used to investigate the influence of benzotriazole (BTA), sulfosalicylic acid (SSA), H2O2, and temperature on the corrosion resistance of pre-passivation film formed on copper. The optimal pre-passivation process was predicted: BTA of 14–16 g/L, SSA of 2–2.3 g/L, H2O2 of 10–11 ml/L, sodium dodecylsulfate of 0.5 g/L and temperature of 45–50 °C. An improved pre-passivation treatment suitable for B30 alloy, using H3PO4 instead of SSA, showed good corrosion resistance; the polarization resistance increased nearly 100 times in its ‘infancy’. In the 30 days of corrosion test, the localized corrosion was significantly inhibited, thus prolonging the service life of the heat-transfer tube.