Effect of Cathodic Polarisation Switch-Off on the Passivity and Stability to Crevice Corrosion of AISI 304L Stainless Steel

The effects of cathodic polarisation switch-off on the passivation of AISI 304L stainless steel in air and its crevice corrosion susceptibility in 3.5 wt.% NaCl aqueous electrolyte were investigated. Scanning Kelvin probe (SKP) data showed that the oxide film is significantly destabilised and the rate of steel passivation in air is slowed down. Thermal desorption analysis (TDA) highlighted that hydrogen absorption is proportional to the applied cathodic current density. A special crevice corrosion set-up was designed to realise simultaneous reproducible monitoring of potential and galvanic current to study the impact of prior cathodic polarisation on crevice corrosion onset.

Automated summary

The study found that turning off cathodic polarization destabilizes the oxide film, slowing down the passivation rate of the stainless steel in air, while hydrogen absorption is proportional to the applied cathodic current density. A special crevice corrosion set-up was designed to monitor potential and galvanic current simultaneously, to study the impact of prior cathodic polarization on crevice corrosion onset.