Use of Electrochemical Tests for Assessment of the Effect of Erosive Particle Size on the Erosion-Corrosion Behaviour of AISI 304L Austenitic Stainless Steel

The degradation of AISI 304L stainless steel under static corrosion, liquid impingement and corrosion-erosion was studied using polarization curves. Static corrosion and liquid impingement tests were performed in 3.5% NaCl solution. Corrosion-erosion tests were performed in the same solution, containing 10 wt-% of three different SiO₂ particle sizes. Synergism between erosion and corrosion was correlated to shifts in the polarization curves. The passive current densities increased and the pitting potential decreased for liquid impingement and with addition of SiO₂ particles to the electrolyte. Increasing the particle size led to a greater increase in the current densities, although the pitting potential did not significantly changed. The effects of erosion on corrosion are discussed in terms of the passive film breakdown and reformation.

Keywords:
Erosion-corrosion synergism; Austenitic stainless steel; Electrochemical techniques; Polarization curves