Erosion–corrosion of 2205 duplex stainless steel in flowing seawater containing sand particles

2205 duplex stainless steel (UNS S31803) was tested in flowing artificial seawater containing sand particles using a jet impingement apparatus. Erosion–corrosion was measured under a range of hydrodynamic conditions by recording the increase in anodic current density that occurred when the passive film was damaged by particle impacts. The current density increase was shown to be linearly related to the mean kinetic energy of the sand particles. When the stainless steel was held at anodic potentials the surface oxide film developed optical interference colours and these colours were used to identify the film thickness. The highest rate of erosion–corrosion occurred in the stagnation region, immediately beneath the jet, where the particles impacted the surface at angles close to 90°. The results are discussed in terms of the rates of particle impacts and their effects on the processes of film damage and repassivation.