Correlation between depassivation and repassivation processes determined by single particle impingement: Its crucial role in the phenomenon of critical flow velocity for erosion-corrosion

The correlation between depassivation and repassivation processes, which is significant in erosion corrosion, was quantitatively investigated by single particle impingement tests at various flow velocities and impact angles. The results show that both repassivation and depassivation processes are associated with the kinetic energy of solid particle, and demonstrate that the repassivation is retarded by depassivation. This phenomenon probably results from the depassivation-induced microstructure evolution. On this basis, the dependence of critical flow velocity (CFV) for erosion-corrosion on the solid particle concentration and diameter is further theoretically predicted and experimentally verified. Accordingly, the crucial role of depassivation-repassivation in CFV phenomenon is further highlighted. (c) 2021 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

The correlation between depassivation and repassivation processes in erosion corrosion was quantitatively investigated through single particle impingement tests, showing that repassivation is retarded by depassivation. The study further predicted and experimentally verified the dependence of critical flow velocity on solid particle concentration and diameter in erosion-corrosion. This highlights the crucial role of depassivation-repassivation in the critical flow velocity phenomenon.