Erosion-enhanced corrosion of stainless steel and carbon steel measured electrochemically under liquid and slurry impingement

•Solutions with/without sands affect erosion-corrosion of carbon steel differently.•Passivation of stainless steel is enhanced by the fluid flow without sands.•An ideal schematic has been built up to explain the electrochemical results.•Passive film is porous under impingement at the velocity beyond the critical value.

The erosion-enhanced corrosion of 304 stainless steel and carbon steel under impingement by NaCl solution has been investigated. With increasing flow velocity, the open-circuit potential of carbon steel increases in the sand-free solution, while decreases in the sand-containing solution. The passive current density of stainless steel under impingement is close to that in quiescent condition in most cases, while increases by an order of magnitude at a flow velocity higher than the critical flow velocity. An ideal schematic has been used to explain the electrochemical results. The passivation of stainless steel under impingement is further analyzed by potentiostatic polarization.